INSTITUT FÜR CHEMIE

1. New Homoleptic Rare-Earth Metal Complexes Comprising the Unsymmetrically Substituted Amidinate Ligand [MeC(NEt)(NtBu)]–

Nicole Harmgarth, Phil Liebing, Liane Hilfert, Volker Lorenz, Felix Engelhardt, Sabine Busse, and Frank T. Edelmann

Z. Anorg. Allgem. Chem. (2019), 645, 1101-1109.

New homoleptic complexes of selected rare-earth elements containing the unsym- metrically substituted amidinate ligand [MeC(NEt)(NtBu)]– [= (L)–] were synthesized and fully characterized. Treatment of in situ-prepared Li(L) (1) with anhydrous lanthanide(III) chlorides, LnCl3 (Ln = Sc, La, Ce, Ho), afforded three different types of amidinate complexes depending on the ionic radius of the central metal atom. The large La3+ formed the octa-coordinate DME solvate La(L)3(DME) (2). Using Ce3+, the octa-coordinate “ate” complex Li(THF)[Ce(L)4] (3) was formed. Depending on the crystallization conditions, compound 3 could be crystallized in two modifications dif- fering in the coordination environment around Li. In the case of the smaller Sc3+ and Ho3+ ions, six-coordinate homoleptic Sc(L)3 (4) and Ho(L)3 (5) were isolated. The title compounds were fully characterized by spectroscopic and analytical methods as well as single-crystal X-ray diffraction. With Ln = La and Ce, several by-products incorpo- rating lithium, chlorine and/or oxygen were also isolated and structurally characterized.

 

2. The Manifold Structural Chemistry of Alkali Metal Enediamide Complexes

Ramesh Duraisamy, Phil Liebing, Nicole Harmgarth, Volker Lorenz, Liane Hilfert, Sabine Busse, Felix Engelhardt, and Frank T. Edelmann

Eur. J. Inorg. Chem. (2019), 3343-3351.

New alkali metal (M = Li, Na, K) enediamide complexes derived from 1,4-diaza-1,3- dienes(= DAD’s) have been synthesized and structurally characterized. The complexes were preparedby direct metalation ofeither1,4-bis(2,6-diisopropylphenyl)-1,4-diaza- 1,3-butadiene (1, = H2DADDipp) or 1,4-bis(2,6-diisopropylphenyl)-2,3-dimethyl-1,4- diaza-1,3-butadiene (2, = Me2DADDipp)with an excess of the respective alkali metals in donor solvents such as THF or DME.All new complexes were fully characterized by spectroscopic methods and X-ray crystallography.

 

3. Synthesis, structure, complexation, and luminescence properties of the first metal- organic curcumin compound Bis(4-triphenylsiloxy)curcumin

Lorenz, Volker; Liebing, Phil; Suta, Markus; Engelhardt, Felix; Hilfert, Liane; Busse, Sabine; Wang, Sida; Wickleder, Claudia; Edelmann, Frank T.

J. Lumin. (2019), 211, 243-250.

The synthesis and structural characterization of 1,7-bis(4-triphenylsiloxy-3-methoxy- phenyl)-1,6-heptadiene-3,5-dione (1 = Ph3SiCurcH) and 1,7-bis(4-methoxycarbonyloxy- 3-methoxy-phenyl)-1,6-heptadiene-3,5-dione (2 = MeOC(O)CurcH) are reported. Compd. 1 represents the first metal-org. curcumin deriv. The complexation of 1 and 2 with Cu2+ has been studied. The new copper(II) complexes (Ph3SiCurc)2Cu (3) and [MeOC(O)Curc]2Cu·4MeCN (4) have been prepd. and their crystal structures detd. by single crystal X-ray diffraction. Moreover, the optical properties of the solid compd. 1 have been investigated in detail. The emission spectrum shows a vibronic fine structure that has been analyzed in terms of Franck-Condon factors. The excitation spectrum is broad and structureless and may be interpreted in terms of an interband transition as is also confirmed by diffuse reflectance spectra. Due to the weak intermol. interactions, an isolated-mol. model is used instead for the assignment of the transitions, which are thus characterized as S1 ↔ S0 or π* ↔ π fluorescent transitions. Despite the elec.-dipole allowed nature of the transition, the quantum yield is Φ = (2.4 ± 0.3)% in agreement with other findings on curcumin derivs.

 

4. Review: the multicolored coordination chemistry of violurate anions

Lorenz, Volker; Liebing, Phil; Engelhardt, Felix; Stein, Franziska; Kuehling, Marcel; Schroeder, Lea; Edelmann, Frank T.

J. Coord. Chem. (2019), 72, 1-34.

A review is presented on the coordination chem. of violuric acid, C4H3N3O4 (= H3Vio), and its derivs. (e.g. 1,3-diorganovioluric acids and thiovioluric acid). The most remarkable property of these colorless compds. is the formation of brightly colored (pantochromic/polychromic) salts with colorless cations such as alkali metal and alk. earth metal ions and organoammonium ions. These magnificent colors have fascinated chemists for more than a century. Only in recent years it was fully recognized that the structural chem. of violurates is rather interesting and diverse. Violurate anions are excellent building blocks for new supramol. assemblies in the cryst. state. Various organoammonium violurates and transition metal violurate complexes were structurally characterized through single-crystal x-ray diffraction. Highly characteristic for these structures is the formation of 1-dimensional, 2- dimensional, or 3-dimensional hydrogen-bonded assemblies in the cryst. state. This review provides a comprehensive overview on the multicolored coordination chem. of violurate anions, with the focus being on structurally characterized species.

 

5. An unsymmetrical dinuclear scandium complex comprising salophen ligands [H2salophen = N,N'-bis(salicylidene)-1,2-phenylenediamine]

Lorenz, Volker; Liebing, Phil; Hilfert, Liane; Busse, Sabine; Edelmann, Frank T.
Acta Cryst., Sect. E: Cryst. Commun. (2019), 75, 175-178.

Treatment of scandium nitrate tetrahydrate with the tetradentate ligand H2salophen [N,N'-bis(salicylidene)-1,2-phenylenediamine] afforded the yellow dinuclear complex Sc(NO3)2(μ-salophen)Sc(salophen)(EtOH) or [Sc2(C20H14N2O2)2(NO3)2(C2H6O)] (systematic name: (ethanol-κO)bis(nitrato-κ2O,O'){μ-2,2'-[1,2- phenylenebis(nitrilomethanylylidene)]diphenolato-κ4N,N',O,O':κ2O,O'}{2,2'-[1,2- phenylenebis(nitrilomethanylylidene)]diphenolato-κ4O,N,N',O'}discandium). In this compd., one salophen ligand displays a bridging coordination via the two oxygen atoms, while the other salophen ligand is attached to only one Sc center. This arrangement is stabilized by a hydrogen-bonded EtOH co-ligand, and by π-π stacking interactions between the two salophen ligands.

 

6. Structural Investigation of New Lithium Amidinates and Guanidinates

Liebing, Phil; Harmgarth, Nicole; Lorenz, Volker; Zoerner, Florian; Hilfert, Liane; Busse, Sabine; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2019), 645, 440-446.

A series of potentially useful lithium amidinates and guanidinates were prepd. and fully characterized. Treatment of N,N'-diisopropylcarbodiimide with phenyllithium in di-Et ether afforded the lithium amidinate [PhC(NiPr)2Li(OEt2)]2 (1). Similar treatment of N,N'-diorganocarbodiimides R'-N=C=N-R' [R' = iPr, cyclohexyl (Cy)] with secondary lithium amides LiNR2 [R2 = Et2, iPr2, (CH2)4] followed by crystn. from THF or 1,4-dioxane gave the lithium guanidinates [R2NC(NR')2Li(S)]2 [2: R = Et, R' = iPr, S = THF; 3: R2 = (CH2)4,R'=iPr,S=THF;4:R=R'=iPr,S=1/21,4-dioxane;5:R2 =(CH2)4,R'=Cy,S= 1,4-dioxane] as cryst. solids. Reaction of N-lithioaziridine with the corresponding carbodiimides afforded solvent-deficient [{C2H4NC(NiPr2)2}2Li2(THF)]2 (6), and [C2H4NC(NEt)(NtBu)Li(THF)]2 (7). Crystal structure detn. revealed the presence of common ladder-type dimeric structures for 1-5. Compd. 6 exists as a dimer of two ladder-type dimers in the crystal, and 7 exhibits an unusual dimeric structure comprising an eight-membered C2N4Li2 ring.

 

7. Formation and structural characterization of a potassium amidinoguanidinate Lorenz, Volker; Liebing, Phil; Hilfert, Liane; Busse, Sabine; Edelmann, Frank T.

Acta Cryst., Sect. E: Cryst. Commun. (2018), 74, 1795-1799.

The first potassium amidinoguanidinate complex, catena-poly[[bis(μ-1-amidinato- N,N',N'',N'''-tetraisopropylguanidinato-κ5N1:N1,N2:N2,N4)dipotassium]-μ-1,2- dimethoxyethane-κ2O:O'], [K2(C14H32N4)2(C4H10O2)]n or [{iPrN= CHN(iPr)N(NiPr)2K}2(μ- DME)]n where DME is 1,2-dimethoxyethane, has been synthesized and structurally characterized. The title compd. was isolated in 76% yield from a reaction of N,N'- diisopropylcarbodiimide with potassium hydride in DME. The single-crystal X-ray structure detn. of the title compd. revealed a polymeric chain structure comprising cage-like dimeric units, with the amidinoguanidinate ligand displaying a mixed σ-/π- coordination mode.

 

8. Synthesis and Structural Investigation of Brightly Colored Organoammonium Violurates

Liebing, Phil; Stein, Franziska; Hilfert, Liane; Lorenz, Volker; Oliynyk, Karyna; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2019), 645, 36-43.

Nine new organoammonium violurates [R1R2R3NH][C4H2N3O4] [R1 = R2 = H, R3 = c-C3H5 (2), R3 = tBu (3), R3 = adamantyl (4), R3 = C6H2Me2-4,5-NH2-2 (5); R1 = H, R2 = R3 = Et (6), iPr(7);R1 =H,R2/R3 =(-CH2-)4 (8);R1 =R2 =R3 =Et(9);R1 =R2 =Me,R3 =(CH2)2NMe2 (10)] were prepd. by treatment of violuric acid (1) with a variety of primary, secondary, and tertiary amines. With the exception of orange 5, all these violurate salts form bright blue or blue-purple cryst. solids. The acidic triethylammonium violurate [NHEt3]H[C4H2N3O4]2·H2O (9a) was isolated in the form of red-violet, plate-like crystals by the reaction of violuric acid hydrate with triethylamine in a molar ratio of 2:1 in ethanol. All compds. were fully characterized by their IR and NMR (1H, 13C) data as well as elemental analyses. X-ray crystal structures detns. of 2, 7, and 9a revealed supramol. self-assembly through networks of N-H···N and N-H···O hydrogen bonds in the cryst. state.

 

9. Electronic and Geometric Structures of Paramagnetic Diazadiene Complexes of Lithium and Sodium

Haeri, Haleh H.; Duraisamy, Ramesh; Harmgarth, Nicole; Liebing, Phil; Lorenz, Volker; Hinderberger, Dariush; Edelmann, Frank. T.

ChemistryOpen (2018), 7, 701-708.

The electronic and mol. structures of the lithium and sodium complexes of 1,4-bis(2,6- diisopropylphenyl)-2,3-dimethyl-1,4-diazabutadiene (Me2DADDipp) were fully characterized by using a multi-frequency ESR (EPR) spectroscopy approach and crystallog., together with d. functional theory (DFT) calcns. EPR measurements, using T1 relaxation-time-filtered pulse EPR spectroscopy, revealed the diagonal elements of the A and g tensors for the metal and ligand sites. It was found that the central metals in the lithium complexes had sizable contributions to the SOMO, whereas this contribution was less strongly obsd. for the sodium complex. Such strong contributions were attributed to structural specifications (e.g. geometrical data and at. size) rather than electronic effects.

 

10. The "Wanderlust" of Me3Si groups in rare-earth triple-decker complexes: a combined experimental and computational study

Lorenz, Volker; Liebing, Phil; Bathelier, Adrien; Engelhardt, Felix; Maron, Laurent; Hilfert, Liane; Busse, Sabine; Edelmann, Frank T.

Chem. Commun. (2018), 54, 10280-10283.

The migration of Me3Si groups (Wanderlust) in rare-earth triple-decker sandwich complexes Ln2(COT'')3 (COT'' = bis(trimethylsilyl)cyclooctatetraenyl) was elucidated by a combined exptl. and computational study. For the 1st time, two isomers of a Ln2(COT'')3 triple-decker were isolated and characterized in the case of Y2(COT'')3.

 

11. Two New Series of Potentially Triboluminescent Lanthanide(III) β-Diketonate Complexes

Margenfeld, Leif-Kenneth; Liebing, Phil; Oehler, Florian; Lorenz, Volker; Engelhardt, Felix; Hilfert, Liane; Busse, Sabine; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2018), 644, 1177-1184.

Two new series of anionic lanthanide(III) tetrakis(dibenzoylmethanato) complexes of the type [C4H8NEtH][Ln(dbm)4] [Ln = Pr (2a), Nd (2b), Eu (2c), Tb (2d), Lu (2e); dbm = dibenzoylmethanate anion; [C4H8NEtH]+ = N-ethylpyrrolidinium cation] and [C5H10NEtH][Ln(dbm)4] [Ln = Pr (3a), Nd (3b), Eu (3c), Tb (3d), Lu (3e); [C5H10NEtH]+ = N- ethylpiperidinium cation]. The results showed that anions of the type [Ln(dbm)4]- are accessible for Ln3+ ions covering a wide range of ionic radii. While neither 2c nor 3c showed the expected triboluminescence (TL) properties, the new TL-active europium(III) complex salt [iPr2NH2][Eu(dbm)4] (4) could be isolated in a similar manner. Moreover, the unexpected formation and structural characterization of the nonanuclear europium cluster Eu9(μ4-OH)2(μ3-OH)8(bnac)16 (5) (bnac = benzoylacetonate anion) is described.

 

12. High-yield synthesis of a unique Mn(III) siloxide complex through KMnO4 oxidation of a Mn(II) precursor

Lorenz, Volker; Ehle, Sophie; Liebing, Phil; Engelhardt, Felix; Hashemi-Haeri, Haleh; Oehler, Florian; Hinderberger, Dariush; Busse, Sabine; Urbaschok, Jens; Edelmann, Frank T.

Dalton Trans. (2018), 47, 62-66.

A unique trivalent manganese siloxide complex, blue-violet MnIIILi2Cl[(Ph2SiO)2O]2(THF)4·2THF (3) has been prepd. by a straightforward two-step synthetic protocol. Lithiation of (Ph2SiOH)2O (1) followed by reaction with MnCl2(THF)2 gave the structurally remarkable Mn(II) precursor MnIILi4Cl2[(Ph2SiO)2O]2(THF)5·2THF (2). Surprisingly, the final oxidn. step could be achieved using KMnO4 in THF to provide the Mn(III) species 3 in high yield (91%). Both title compds. were structurally characterized by single-crystal X-ray diffraction.

 

13. Lanthanide(III) Sandwich and Half-Sandwich Complexes with Bulky Cyclooctatetraenyl Ligands: Synthesis, Structures, and Magnetic Properties

Lorenz, Volker; Liebing, Phil; Boehme, Michael; Buchholz, Axel; Plass, Winfried; Geue, Niklas; Hilfert, Liane; Busse, Sabine; Engelhardt, Felix; Hrib, Cristian G.; Edelmann, Frank, T.

Eur. J. Inorg. Chem. (2017), 4840-4849.

Five new lanthanide(III) sandwich and half-sandwich complexes with bulky cyclooctatetraenyl ligands have been prepd. and fully characterized, including single- crystal X-ray structure detn. The treatment of anhyd. lanthanide(III) chlorides, LnCl3 (Ln = Pr, Tb, Yb), with 2 equiv of Li2COT'' [COT'' = 1,4- bis(trimethylsilyl)cyclooctatetraene dianion] followed by crystn. in the presence of a coordinating solvent afforded the anionic sandwich complexes [Li(THF)4][Pr(COT'')2] (1), [Li(DME)3][Tb(COT'')2] (2; DME = 1,2-dimethoxyethane), and [Li(TMEDA)2][Yb(COT'')2] (3; TMEDA = N,N,N',N'-tetramethylethylenediamine). Attempted oxidn. of 2 with silver iodide did not afford the neutral terbium(IV) sandwich complex [Tb(COT'')2]. Instead, the tri(μ-iodido)-bridged dinuclear half- sandwich complex [Li(DME)2][Tb2(μ-I)3(COT'')2] (4) was isolated in 72 % yield. In this complex, the Li(DME)2 fragment is attached to one of the μ-iodido ligands. A closely related binuclear lutetium complex, [Li(DME)3][Lu2(μ-Cl)3(COTbig)2]·DME (5), was obtained by using the "superbulky" COTbig ligand [COTbig = 1,4- bis(triphenylsilyl)cyclooctatetraenyl dianion]. In addn. to the spectroscopic and structural characterization, the magnetic properties of the paramagnetic terbium(III) deriv. 2 have been investigated and further complemented by ab initio computational methods. These results have been used to discuss the structural requirements for potential terbium(III) single-ion magnets.

 

14. Synthesis and Structural Characterization of Homo- and Heterometallic Li and Li/Ln Disiloxanediolate Complexes

Rausch, Janek; Liebing, Phil; Lorenz, Volker; Hrib, Cristian G.; Ali, Asim; Gross, Patrick; Hilfert, Liane; Busse, Sabine; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2017), 643, 1920-1928.

A series of new homo- and heterometallic lithium and lithium/lanthanide disiloxanediolate complexes were prepd. and fully characterized. Three new adducts of dilithium tetraphenyldisiloxanediolate, [(Ph2SiOLi)2O] (2), with simple Lewis bases (Et2O, THF, DME) were prepd. by treatment of Ph2Si(OH)OSiPh2(OH) (1) with 2 equiv. of n-butyllithium in the resp. donor solvent. This way the adducts [{Ph2SiOLi(Et2O)}2O]2 (3), [{Ph2SiOLi(THF)}2O]2 (4), and [{Ph4Si2O(OLi)2}2(DME)3]∞ (5a) were obtained in a straightforward manner and in nearly quant. yields. Treatment of anhyd. lanthanide(III) chlorides LnCl3 (Ln = Tb, Lu) with 2 equiv. of 2 in THF afforded the new lanthanide(III) bis(disiloxanediolate) complexes [{(Ph2SiO)2O}2{Li(THF)2}2]TbCl (6) and [{(Ph2SiO)2O}2{Li(THF)2}2]LuCl (7) in high yields. Similar reactions of LnCl3 (Ln = Ce, Nd) with 3 equiv. of 2 provided the heterometallic Li/Ln tris(disiloxanediolate) complexes [{(Ph2SiO)2O}3{Li(DME)}2{Li(THF)}]Ce (8) and [{(Ph2SiO)2O}3{Li(DME)}{Li(Et2O)}{Li(THF)}]Nd (9). All title compds. were structurally characterized through single-crystal X-ray diffraction.

 

15. Preparation and crystal structures of silyl-substituted potassium cyclooctatetraenides

Lorenz, Volker; Liebing, Phil; Rausch, Janek; Blaurock, Steffen; Hrib, Cristian G.; Hilfert, Liane; Edelmann, Frank T.

J. Organomet. Chem. (2018), 857, 38-44.

Cyclooctatetraenyl complexes of potassium are readily available by the reaction of silyl-substituted cyclooctatrienes C8H8-1,4-(SiR3)2 (SiR3 = SiMe3, SiMet2Bu, SiPh3) with potassium hydride or potassium metal. While C8H8-1,4-(SiMe3)2 gave a mixt. of K2{C8H6-1,3-(SiMe3)2} (1a) and K2{C8H7-SiMe3} (1b), the substitution pattern on the COT ring remained unchanged in the case of C8H8-1,4-(SiMet 2Bu)2 and C8H8-1,4-(SiPh3)2. [{K2{C8H6-1,4-(SiMet 2Bu)2}(PhMe)}∞] (2) crystallizes in the absence of DME, featuring a μ4-bridging COT ring, while in [K2(C8H6-1,4-(SiPh3)2)(DME)4] (3) the substituted COT ligand adopts a highly sym. μ-η8:η8-coordination, resulting in an "inverse sandwich" architecture. Compd. 3 could be oxidized by treatment with iodine to give the corresponding neutral cyclooctatetraene deriv. C8H6-1,4-(SiPh3)2 (4).

 

16. Synthesis and Structural Characterization of New Zirconium(IV) Bent Metallocenes comprising η8-Cyclooctatetraenyl and Bulky Cyclopentadienyl Ligands

Rausch, Janek; Liebing, Phil; Kuehling, Marcel; Lorenz, Volker; Hrib, Cristian G.; Hilfert, Liane; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2017), 643, 1063-1066.

The new zirconium bent metallocenes (COT)Zr(CptBu2)Cl (1) and (COT)Zr(Cp'')Cl (2) were synthesized in a straightforward manner and in high yields (1: 91 %, 2: 86 %) by treatment of in situ-prepd. (COT)ZrCl2(THF) with 1 equiv. of K(CptBu2) or K(Cp''), resp. [COT = η8-cyclooctatetraenyl; CptBu2 = η5-1,3-di-tert-butylcyclopentadienyl; Cp'' = η5- 1,3-bis(trimethylsilyl)cyclopentadienyl]. Subsequent reaction of 1 with 1 equiv. of phenyllithium afforded the σ-Ph deriv. (CptBu2)Zr(COT)Ph (3) as orange crystals in 83 % isolated yield. All three new compds. were structurally characterized through single- crystal X-ray diffraction.

 

17. Scandium-Mediated Formation of a Bis(tetrahydropentalene)

Rausch, Janek; Liebing, Phil; Lorenz, Volker; Hilfert, Liane; Busse, Sabine; Maichle- Moessmer, Caecilia; Edelmann, Frank T.

Angew. Chem., Int. Ed. Engl. (2017), 56, 7238-7241.

The reactivity of Li[Sc(COT'')2] (1; COT''= 1,4-bis(trimethylsilyl)cyclooctatetraenyl) towards CoCl2 is considerably different from that of related lanthanide triple-decker sandwich complexes. In addn. to the expected triple-decker complex Sc2(COT'')3 (2), the complex Sc2{μ-BTHP}(COT'')2 (3) is formed, which comprises the novel BTHP2- ligand (BTHP2-= bis(3,5-bis(trimethylsilyl)-1,3a,6,6a-tetrahydropentalene-1-yl)diide or bis(2,7-bis(trimethylsilyl)bicyclo[3.3.0]octa-2,7-dien-4-yl)diide, C16H10(SiMe3)4 2-). The formation of 3 is likely facilitated by the fact that Sc prefers η8,η3 coordination rather than highly sym. η8,η8 coordination, and the η3-coordinated COT'' ligand in 1 is activated owing to a loss of aromaticity. Acid hydrolysis of 3 leads to air-stable H2BTHP (4).

 

18. Synthesis and structural study of new metallasilsesquioxanes of potassium and uranium

Giessmann, Stephan; Lorenz, Volker; Liebing, Phil; Hilfert, Liane; Fischer, Axel; Edelmann, Frank T.

Dalton Trans. (2017), 46, 2415-2419.

The first metallasilsesquioxanes comprising potassium and uranium were synthesized and structurally characterized by single-crystal x-ray diffraction. (Cy7Si7O12)2K6(DME)4 (2; Cy = cyclohexyl) is a centrosym. dimer in which the two silsesquioxide ligands are interconnected by μ3- and μ4-bridging siloxide moieties. (Cy7Si7O12)2UVI (3) represents the first metallasilsesquioxane complex of an actinide element, featuring a U atom that is coordinated by two tridentate silsesquioxide ligands in a distorted octahedral fashion. The different structural effects of the large metal at. radii are discussed.

 

19. Crystal structures of two ytterbium(III) complexes comprising alkynylamidinate ligands

Wang, Sida; Sroor, Farid M.; Liebing, Phil; Lorenz, Volker; Hilfert, Liane; Edelmann, Frank T.

Acta Cryst., Sect. E: Cryst. Commun. (2016), 72, 1229-1233.

Two ytterbium(III) complexes comprising alkynylamidinate ligands, namely bis(η5- cyclopentadienyl)(3-cyclopropyl-N,N'-diisopropylpropynamidinato- κ2N,N')ytterbium(III), [Yb(C5H5)2(C12H19N2)] or Cp2Yb[(iPr2N)2C-C≃C-c-C3H5] (1) and tris(3-phenyl-N,N'-dicyclohexylpropynamidinato-κ2N,N')ytterbium(III), [Yb(C21H27N2)3] or Yb[(CyN)2C-C≃C-Ph]3 (Cy = cyclohexyl) (2) have been synthesized and structurally characterized. Both complexes are monomers; for complex 2, the contribution to the scattering from highly disordered toluene solvent mols. in these voids was removed with the SQUEEZE routine [Spek (2015). Acta Cryst. C71, 9-18] in PLATON. The stated crystal data for Mr, μ etc. do not take these into account.

 

20. Synthesis and structural characterization of two complex tantalum(V) siloxides

Ehle, Sophie; Lorenz, Volker; Liebing, Phil; Hilfert, Liane; Edelmann, Frank T.

Inorg. Chem. Commun. (2016), 74, 82-85.

The reaction of tantalum(V) ethoxide, Ta(OEt)5, with 1 equiv. of 1,1,3,3-tetraphenyl- disiloxane-1,3-diol, (HO)SiPh2OSi-Ph2(OH) (1), afforded the dinuclear tantalum(V) disiloxanediolate complex [{μ-(Ph2OSiO)2O}Ta(OEt)2(μ-OEt)]2 (3). Similarly, Ta(OEt)5 reacted with the incompletely condensed silsesquioxane precursor Cy7Si7O9(OH)3 (2, Cy = cyclohexyl) in a 1:1 molar ratio to afford the dinuclear tantalasilsesquioxane deriv. [Cy7Si7O12Ta(OEt)(μ-OEt)]2 (4) in 80% yield. Both new complexes were structurally characterized by single-crystal X-ray diffraction studies.

 

21. Crystal Structures and Hydrogen Bonding of Two Complexes containing the [Ammine-chlorido-ethylenediamine-bis(pyridine)cobalt(III)]2+ Cation
Liebing, Phil; Hilfert, Liane; Lorenz, Volker; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2016), 642, 1178-1183.

The crystal structures of two classical Co(III) complexes comprising the [CoCl(NH3)(en)(py)2]2+ cation were detd. by single-crystal x-ray diffraction. Both complexes, dark red [CoCl(NH3)(en)(py)2]Cl2·H2O (1) and purple [CoCl(NH3)(en)(py)2][HgCl4]·1.125H2O (2), crystallize in the triclinic space group P1̅. In both compds., the Co atom exhibits a typical octahedral coordination and the configuration index of the complex is OC-6-43. In the case of 1, the asym. unit comprises one formula unit, whereas there are two formula units in the case of the tetrachloridomercurate 2. Complex cations, anions, and crystal H2O mols. are interconnected by various N-H···N, N-H···Cl, N-H···O, O-H···Cl, and O-H···O bridge bonds. As a result, 1 features a two-dimensional layer structure and 2 exists as a three-dimensional network.

 

22. A comparative IR/Raman, X-ray and computational study of diethylzinc pyridine complexes

Brueser, Wolfgang; Hilfert, Liane; Lorenz, Volker; Hrib, Cristian G.; Bode, Karin; Adam, Arnold; Vogt, Jochen; Edelmann, Frank T.

J. Organomet. Chem. (2016), 806, 77-82.

The liq. diethylzinc-pyridine adducts Et2Zn(py) (1, py = pyridine) and Et2Zn(py)2 (2) have been investigated in detail by IR and Raman spectroscopy. Furthermore, the crystal structure of 2 has been detd. for the first time by X-ray diffraction. The structures of 1 and 2 and the assignment of vibrational modes are supported by quantum chem. calcns.

 

23. Surprising reactivity of the unsymmetrically substituted amidinate anion [MeC(NEt)(NtBu)]

Schmielau, Andrea; Hrib, Cristian G.; Lorenz, Volker; Hilfert, Liane; Zoerner, Florian; Busse, Sabine; Edelmann, Frank T.

J. Organomet. Chem. (2015), 791, 252-257.

Three unexpected products derived from the unsym. substituted amidinate anion [MeC(NEt)(NtBu)]- are reported. Treatment of 1-tert-butyl-3-ethyl-carbodiimide, tBu- N:C:N-Et, with 1 equiv of MeLi in Et2O afforded colorless crystals of the unusual octanuclear Li amidinate deriv. {[LiN(Et)C(Me)N(tBu)]2·LiN(Et)C(CH2Li)N(tBu)Et2O}2 (1) in 57% yield instead of the expected Li amidinate Li[MeC(NEt)(NtBu)]. In the mol. of 1, one central Me group in a trimer of Li[MeC(NEt)(NtBu)] is deprotonated and two of these partially deprotonated trimers are linked through a central eight-membered [C- N-Li-CH2]2 ring to afford the octanuclear product 1. The same reaction carried out in 1,2-dimethoxyethane (DME) soln. produced the O-centered, heptanuclear Li amidinate cluster {Li[MeC(NEt)(NtBu)]}5·Li2O (2) (21% yield). Treatment of anhyd. PrCl3 with in situ-prepd. Li[MeC(NEt)(NtBu)] in Et2O/THF afforded green (THF)Li[Pr{MeC(NEt)(NtBu)}4] (3) as the 1st anionic tetrakis(amidinato)lanthanide(III) complex in 55% isolated yield. The mol. and crystal structures of all three new compds. were elucidated by x-ray diffraction.

 

24. One ligand fits all: lanthanide and actinide sandwich complexes comprising the 1,4- bis(trimethylsilyl)cyclooctatetraenyl (COT'') ligand

Rausch, Janek; Apostolidis, Christos; Walter, Olaf; Lorenz, Volker; Hrib, Cristian G.; Hilfert, Liane; Kuehling, Marcel; Busse, Sabine; Edelmann, Frank T.

New J. Chem. (2015), 39, 7656-7666.

The series of anionic lanthanide(III) sandwich complexes [Ln(COT'')2]- (COT'' = 1,4- bis(trimethylsilyl)cyclooctatetraenyl dianion) were largely extended by the synthesis of eight new derivs. ranging from La to Lu. [Li(DME)3][Ln(COT'')2] (Ln = Y (1), La (2), Pr (3), Gd (4), Tm (6), Lu (8)) and [Li(THF)4][Ln(COT'')2] (Ln = Ho (5), Tm (7)) were prepd. in good yields following a straightforward synthetic protocol which involves the treatment of LnCl3 with 2 equiv of in situ-prepd. Li2COT'' in either DME (1,2- dimethoxyethane) or THF. The neutral actinide sandwich complexes An(COT'')2 (An = Th (9), U (10)) and An(COT''')2 (COT''' = 1,3,6-tris(trimethylsilyl)cyclooctatetraenyl dianion; An = Th (11), U (12)) were synthesized in a similar manner, starting from ThCl4 or UCl4, resp. The COT'' ligand imparts excellent soly. even in low-polar solvents as well as excellent crystallinity to all new compds. studied. All twelve new f-element sandwich complexes were structurally authenticated by single-crystal x-ray diffraction. All are nearly perfect sandwich complexes with little deviation from the coplanar arrangement of the substituted COT'' rings. Surprisingly, all six [Li(DME)3][Ln(COT'')2] complexes covering the entire range of Ln3+ ionic radii from La3+ to Lu3+ are isostructural (space group P1̅). Compd. 10 is the 1st uranocene deriv. for which 13C NMR data are reported.

 

25. Metal complexes of curcumin - synthetic strategies, structures and medicinal applications

Wanninger, Simon; Lorenz, Volker; Subhan, Abdus; Edelmann, Frank T.

Chem. Rev. (2015), 44, 4986-5002.

This Tutorial Review presents an overview on the synthesis, characterization and applications of metal complexes contg. curcumin (=1,7-bis(4-hydroxy-3- methoxyphenyl)-1,6-heptadiene-3,5-dione) and its derivs. as ligands. Innovative synthetic strategies leading to sol. and crystallizable metal curcumin complexes are outlined in detail. Special emphasis is placed on the highly promising and exciting medicinal applications of metal curcumin complexes, with the three most important areas being anticancer activity and selective cytotoxicity, anti-Alzheimer's disease activity, and antioxidative/neuroprotective effects. Overall, this Tutorial Review provides the first general overview of this emerging and rapidly expanding field of interdisciplinary research.

 

26. Synthesis and structure of hexaphenyltrisiloxanediolates of sodium, titanium, and iron

Ali, Asim; Langer, Mirko; Lorenz, Volker; Hrib, Cristian G.; Hilfert, Liane; Edelmann, Frank T.

J. Organomet. Chem. (2015), 776, 163-169.

The syntheses and single-crystal x-ray structures of several well-defined hexaphenyltrisiloxanediolates of sodium, titanium, and iron are reported. All these compds. contain eight-membered MSi3O4 rings (M = Na, Ti, Fe). Treatment of 1,1,3,3- tetraphenyldisiloxane-1,3-diol, (HO)SiPh2OSiPh2(OH) (1), with excess metallic Na in THF afforded the sodium-hexaphenyltrisiloxandiolate reagent [Ph2Si(OSiPh2O)2]2Na4(THF)4 (3a) in 68% yield. Single crystals suitable for x-ray diffraction were obtained for the diglyme solvate [Ph2Si(OSiPh2O)2]2Na4(diglyme)2 (3b) which was prepd. in 76% yield by recrystn. of 3a from diglyme (ethylene-bis(2-methoxyethyl)ether). Readily accessible 3a is a highly useful precursor for new transition metal hexaphenyltrisiloxanediolates (=metallacyclotetrasiloxanes). Reaction of 3a with an excess of TiCl4 in THF provided the titanacyclotetrasiloxane deriv. [Ph2Si(OSiPh2O)2]TiCl2(THF)2 (4) with octahedral coordination around titanium. Similar reaction of 3a with FeCl3 in THF afforded the anionic spirocyclic iron(III) complex [Na(DME)3][{Ph2Si(OSiPh2O)2}2Fe] (5) as yellow- brown crystals in 71% yield. An iron(III) analog of 4, the anionic ferracyclotetrasiloxane complex [Li(DME)3][Ph2Si(OSiPh2O)2FeCl2] (6) was prepd. in moderate yield (53%) by deprotonation of 1,1,3,3,5,5-hexaphenyl-1,3,5-trisiloxanediol, Ph2Si(OSiPh2OH)2 (2), with n-butyllithium followed by reaction with FeCl3 in DME. The mol. and crystal structures of 3b, 4, 5, and 6 were detd. by x-ray diffraction.

 

27. Heterometallic Europium Disiloxanediolates: Synthesis, Structural Diversity, and Photoluminescence Properties

Rausch, Janek; Lorenz, Volker; Hrib, Cristian G.; Frettloeh, Vanessa; Adlung, Matthias; Wickleder, Claudia; Hilfert, Liane; Jones, Peter G.; Edelmann, Frank T.

Inorg. Chem. (2014), 53, 11662-11674.

This contribution presents a full account of a structurally diverse class of heterometallic europium disiloxanediolates. The synthetic protocol involves in situ metalation of (HO)SiPh2OSiPh2(OH) (1) with either BuLi or KN(SiMe3)2 followed by treatment with EuCl3 in suitable solvents such as 1,2-dimethoxyethane (DME) or THF. Reaction of EuCl3 with 2 equiv of (LiO)SiPh2OSiPh2(OLi) in DME afforded the EuIII bis(disiloxanediolate) "ate" complex [{(Ph2SiO)2O}2{Li(DME)}3]EuCl2 (2), which upon attempted redn. with Zn gave the tris(disiloxanediolate) [{(Ph2SiO)2O}3{Li(DME)}3]Eu (3). Treatment of EuCl3 with (LiO)SiPh2OSiPh2(OLi) in a molar ratio of 1:2 yielded both the ate complex [{(Ph2SiO)2O}3Li{Li(THF)2}{Li(THF)}]EuCl·Li(THF)3 (4) and the LiCl-free europium(III) complex [{(Ph2SiO)2O}2{Li(THF)2}2]EuCl (5). Compd. 5 exhibits a brilliant red triboluminescence. When (KO)SiPh2OSiPh2(OK) was used as starting material in a 3:1 reaction with EuCl3, the EuIII tris(disiloxanediolate) [{(Ph2SiO)2O}3{K(DME)}3]Eu (6) was isolated. Attempted ligand transfer between 5 and (DADDipp)2Ba(DME) (DADDipp = N,N'-bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene) afforded the unique mixed- valent EuIII/EuII disiloxanediolate cluster [(Ph2SiO)2O]6EuII 4EuIII 2Li4O2Cl2 (7). All new complexes were structurally characterized by x-ray diffraction. Photoluminescence studies were carried out for complex 5 showing an excellent color quality, due to the strong 5D0→7F2 transition, but a weak antenna effect.

 

28. Synthesis and structure of a heterotrimetallic (Li/Er/In), heptacyclic metallasiloxane cage compound

Lorenz, Volker; Hrib, Cristian G.; Jones, Peter G.; Edelmann, Frank T.

Inorg. Chem. Commun. (2014), 49, 37-40.

The unusual heterotrimetallic (Li/Er/In), heptacyclic metallasiloxane cage compd. [{(Ph2SiO)2O}3{Li(THF)2}{InMe}]Er (2) has been prepd. in 98% yield by reaction of the erbium bis(disiloxanediolate) deriv. [{(Ph2SiO)2O}2{Li(THF)2}2]ErCl (1) with trimethylindium, InMe3. The product was structurally characterized by single-crystal x- ray diffraction.

 

29. Unprecedented formation of polycyclic diazadiborepine derivatives through cage deboronation of m-carborane

Harmgarth, Nicole; Hrib, Cristian G.; Lorenz, Volker; Hilfert, Liane; Edelmann, Frank T. Chem. Commun. (2014), 50, 13239-13242.

An unprecedented deboronation reaction of icosahedral carboranes is described, in which a BH group of m-carborane is detached from the cage and incorporated into an unusual nido-carborane-annellated diazadiborepine ring system.

 

30. Carboranylamidinates of di- and trivalent iron

Hillebrand, Philipp; Hrib, Cristian G.; Harmgarth, Nicole; Jones, Peter G.; Lorenz, Volker; Kuehling, Marcel; Edelmann, Frank T.

Inorg. Chem. Commun. (2014), 46, 127-129.

For the first time, carboranylamidinates of a transition metal in two different oxidn. states have been prepd. The iron carboranylamidinates [o-C2B10H10C(NHiPr)(= NiPr)- κ2C,N]2FeIIICl (3) and [o-C2B10H10C(NHiPr)(= NiPr)-κ2C,N]2FeII (4) were simultaneously formed in low yields upon treatment of anhyd. FeCl3 with 2 equiv. of [o- C2B10H10C(NHiPr)(= NiPr)-κ2C,N]Li(DME) (2) in THF soln. Both products were structurally characterized by single-crystal X-ray diffraction.

 

31. Novel inorganic heterocycles from dimetalated carboranylamidinates

Harmgarth, Nicole; Graesing, Daniel; Droese, Peter; Hrib, Cristian G.; Jones, Peter G.; Lorenz, Volker; Hilfert, Liane; Busse, Sabine; Edelmann, Frank T.

Dalton Trans. (2014), 43, 5001-5013.

Mono- and dianionic carboranylamidinates are readily available in one-pot reactions directly from o-carborane (1). In situ-monolithiation of 1 followed by treatment with N,N'-diisopropylcarbodiimide, iPrN:C:NiPr, or N,N'-dicyclohexylcarbodiimide, CyN:C:NCy, provided the lithium carboranylamidinates (o-C2B10H10C(NHiPr)(:NiPr)- κ2C,N)Li(DME) (2a) and (o-C2B10H10C(NHiCy)(:NiCy)-κ2C,N)Li(THF)2 (2b). Controlled hydrolysis of 2a,b afforded the free carboranylamidines o-C2B10H11C(NHiR)(:NiR) (3a: R = iPr, 3b: R = Cy). The first dimetalated carboranylamidinates, o- C2B10H10C(NiPr)(:NiPr)Li2(DME)2 (4a) (DME = 1,2-dimethoxyethane) and o- C2B10H10C(NiPr)(:NiPr)Li2(THF)4 (4b), were prepd. in high yield (83% yield) directly from 1 using a simple one-pot synthetic protocol. Treatment of 4b with 2 equiv. of Me3SiCl afforded the disilylated deriv. o-C2B10H10-κ2C,N-[C(NiPrSiMe3)(:NiPr)]SiMe3 (5). Dianionic 4b also served as an excellent precursor for novel inorg. heterocycles incorporating the closo-1,2-C2B10H10 cage, including the unsym. distannene [o- C2B10H10C(NiPr)(:NiPr)-κ2C,N]Sn:Sn[(iPrN)2CnBu]2 (6) and the azaphosphole deriv. [o- C2B10H10C(NiPr)(:NiPr)-κ2C,N]PPh (7). Surprisingly, it was found that the synthesis of new inorg. ring systems from dianionic carboranylamidinates can also be achieved by employing only 1 equiv. of n-butyllithium in the generation of the anionic carboranylamidinate intermediates. Using this straightforward one-pot synthetic protocol, the Group 14 metallacycles [o-C2B10H10C(NCy)(:NCy)-κ2C,N]SiR2 (R = Cl (8), Me (9), Ph (10)) and [o-C2B10H10C(NCy)(:NCy)-κ2C,N]GeCl2 (11) have become accessible. The same synthetic strategy could be successfully adapted to prep. the corresponding Group 4 metallocene derivs. Cp2Ti[o-C2B10H10C(NCy)(:NCy)-κ2C,N] (12) and Cp2Zr[o- C2B10H10C(NCy)(:NCy)-κ2C,N] (13). The mol. structures of 2b, 3b, 4b, 5, 6, 7, 10, 12, and 13 were confirmed by single-crystal x-ray diffraction.

 

32. Diazadiene Complexes of the Heavy Alkaline-Earth Metals Strontium and Barium: Structures and Reactivity

Lorenz, Volker; Hrib, Cristian G.; Grote, Dirk; Hilfert, Liane; Krasnopolski, Michael; Edelmann, Frank T.

Organometallics (2013), 32, 4636-4642.

1,4-Diaza-1,3-diene (DAD) complexes of the heavy alk.-earth metals Sr and Ba were synthesized by direct metalation of N,N'-bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene (1, = DADDipp). The reaction with Sr metal afforded a mixt. of the red enediamide-type deriv. (DADDipp)Sr(DME)2 (2, DME = 1,2-dimethoxyethane) and black (DADDipp)2Sr(DME) (3), which contains two coordinated DAD radical anions. With Ba, only the radical anion deriv. (DADDipp)2Ba(DME) (4) was formed in 82% yield. For the 1st time, transfer of a DAD radical anion ligand from an alk.-earth metal to a rare-earth metal was achieved. Reaction of 4 with [{(Ph2SiO)2O}2{Li(THF)2}2]HoCl (5) afforded the novel (DAD)holmium bis(disiloxanediolate) complex [{(Ph2SiO)2O}2{Li(THF)2}2]Ho(DADDipp) (6). All new complexes (2-4 and 6) were structurally characterized by x-ray diffraction. The radical anion complexes 3, 4, and 6 were characterized by their EPR spectra.

 

33. Linear Heterometallic Co3Li2 and Co4Li2 Siloxides: Precursors for the Plasma Synthesis of Adsorbent Materials

Ehle, Sophie; Brueser, Volker; Lorenz, Volker; Hrib, Cristian G.; Saulich, Katja; Mueller, Siegfried; Quade, Antje; Edelmann, Frank T.

Eur. J. Inorg. Chem. (2013), 1451-1457.

New linear heterometallic Co3Li2 and Co4Li2 arrays were assembled using disiloxanediolate and silsesquioxane ligands. Treatment of anhyd. CoCl2 with in situ- prepd. (Ph2SiOLi)2O afforded (THF)Co[Co{μ-(Ph2SiO)2O}{(μ-Cl)2Li(THF)2}]2 (5) as dark blue prisms in 73% yield, while the analogous reaction of CoCl2 with in situ-prepd. Cy7Si7O9(OLi)3 (Cy = cyclohexyl) gave royal blue [Co2(μ-Cy7Si7O12)(μ-OSiMe3)(μ- Cl){Li(THF)2}2]2 (6) in 68% yield. Both of the new compds. were structurally characterized by x-ray crystallog. Plasma treatment of 5 was found to activate the surface by creating -C-O, -C:O, and -COO functionalities. An initial study revealed promising formaldehyde adsorption properties for the plasma-treated material 5a.

 

34. Steric Effects in Lanthanide Sandwich Complexes Containing Bulky Cyclooctatetraenyl Ligands

Edelmann, Anja; Lorenz, Volker; Hrib, Cristian G.; Hilfert, Liane; Blaurock, Steffen; Edelmann, Frank T.

Organometallics (2013), 32, 1435-1444.

This paper gives a full account of the complex reaction system LnCl3/(COT'')2- (COT'' = 1,4-bis(trimethylsilyl)cyclooctatetraenyl dianion). Four different series of organolanthanide complexes of this bulky COT ligand have been reported: (1) anionic sandwich complexes contg. [Ln(COT'')2]- anions, (2) dimeric chloro-bridged mono(COT'') complexes, (3) cluster-centered multidecker-sandwich complexes, and (4) linear triple-decker sandwich complexes. In order to get a more complete picture of the reaction system LnCl3/(COT'')2- and to examine possible steric effects exerted by the COT'' ligand, four new rare-earth-metal COT'' complexes have been prepd.: [Li(DME)3][Ce(COT'')2] (1), [Li(THF)4][Nd(COT'')2] (2), [(COT'')Nd(μ-Cl)(THF)]2 (4), and (COT'')Yb(DIPPForm)(THF) (5; DIPPForm = [HC(NAr)2]-, Ar = 2,6-diisopropylphenyl). For comparison, the COTTBS deriv. [Li(DME)3][Ce(COTTBS)2] (3; COTTBS = 1,4-bis(tert- butyldimethylsilyl)cyclooctatetraenyl dianion) has also been synthesized. It was found that the steric effect of either COT'' or COTTBS on the mol. structures of the anionic sandwich complexes 1-3 with coplanar ring ligands is rather small. In (COT'')Yb(DIPPForm)(THF) (5), the combination of COT'' with a sterically demanding formamidinate ligand in the coordination sphere of Yb3+ still leaves room for THF coordination. For example, in 4, the bulky COT'' leads to coordination of only one THF per Ln in comparison to the parent chloro-bridged dimers [(COT)Ln(μ-Cl)(THF)2]2. However, in the dimeric chloro-bridged mono(COT'') complexes the presence of COT'' reduces the no. of coordinated THF mols. Quite surprisingly, an attempt to prep. the holmium analog of the known linear triple-decker sandwich complex (COT'')Nd(μ- η8:η8-COT'')Nd(COT'') led to formation of the isomerized triple-decker (COT'')Ho[μ- η8:η8-C8H6(SiMe3)2-1,5]Ho(COT'') (6), as a result of steric pressure-induced silyl group migration. All new complexes 1-6 have been structurally characterized by x-ray diffraction.

 

35. Bromidobis[3-(1H-pyrazol-1-yl-κN2)propionamide-κO]copper(II) bromide methanol monosolvate

Wagner, Thomas; Hrib, Cristian G.; Lorenz, Volker; Edelmann, Frank T.; Gilje, John W. Acta Cryst., Sect. E: Struct. Rep. Online (2012), 68, m1253-m1254.

The title Cu(II) N-pyrazolylpropanamide (PPA) complex, [CuBr(PPA)2]Br, was obtained in 78% yield by treatment of CuBr2 with an excess of the ligand in MeOH. Crystn. from the mother liq. afforded the title compd., i.e. the MeOH solvate [CuBr(C6H9N3O)2]Br·MeOH or [CuBr(PPA)2]Br·MeOH, as bright green crystals. Crystallog. data and at. coordinates are given. In the solid state, the title salt comprises isolated [CuBr(PPA)2]+ cations, sepd. bromide ions and MeOH of crystn. In the cation, the central CuII ion is coordinated by two N,O-chelating PPA ligands and one Br- ion. The coordination geometry around the CuII ion is distorted trigonal- bipyramidal with the bromide ligand and the amide O atoms occupying the equatorial positions [Cu-Br = 2.4443(4) Å; Cu-O = 2.035(2) and 2.179(2) Å], while the pyrazole N atoms coordinate in the axial positions [Cu-N = 1.975(2) and 1.976(2) Å]. In the crystal, the three constituents are linked by N-H···Br, O-H···Br, and N-H···O H bonds, forming a three-dimensional network.

 

36. N-Triazolylpropanamide - an Acrylamide-Derived Multifunctional Ligand for the Construction of Supramolecular Hydrogen-Bonded Networks

Wagner, Thomas; Hrib, Cristian G.; Lorenz, Volker; Edelmann, Frank T.; Zhang, Jianfeng; Yi, Qiaohua

Z. Anorg. Allg. Chem. (2012), 638, 2185-2188.

The synthesis and single crystal x-ray structure of the multifunctional acrylamide- derived ligand N-triazolylpropanamide (1, = NTPA) are reported. The title compd. was prepd. in 72% yield by Michael addn. of 1,2,4-triazole and acrylamide in the presence of Triton B (= trimethylbenzylammonium hydroxide) as catalyst. Treatment of 1 with FeCl3·6H2O in MeOH/MeCN led to redn. and formation of the iron(II) complex (NTPA)2FeCl2(MeOH)2 (2, yellow prisms, 52% yield). Both 1 and 2 were structurally characterized by x-ray diffraction. Surprisingly, the NTPA ligands in 2 are coordinated to iron in a monodentate fashion through a triazole ring nitrogen atom. In the crystal, both compds. form supramol. hydrogen-bonded networks.

 

37. N-Pyrazolylpropanamide - a Versatile Ligand for the Construction of Supramolecular Hydrogen-Bonded Frameworks

Wagner, Thomas; Hrib, Cristian G.; Lorenz, Volker; Edelmann, Frank T.; Amenta, Donna S.; Burnside, Christopher J.; Gilje, John W.

Z. Anorg. Allg. Chem. (2012), 638, 2129-2137.

The syntheses and single-crystal x-ray structures of several first-row transition metal complexes contg. the multifunctional acrylamide-derived ligand N-pyrazolylpropanamide (1 = L) are reported. The general synthesis involves treatment of appropriate transition metal salts with an excess of 1 in ethanolic soln. in the presence of triethylorthoformate as dehydrating agent. This way the perchlorates of iron(II) and cobalt(II) afforded the complexes [L2M(EtOH)2](ClO4)2[M = Fe (2), Co (3), in good yields (82 and 85 %)]. Light green L2NiCl2 (4) was obtained analogously from NiCl2·6H2O. Hydration of 4 afforded the dark green cationic nickel(II) complex [L2Ni(H2O)4]Cl2 (4a). In compds. 2-4 the N-pyrazolylpropanamide acts as N, O-chelating ligand. In contrast, monodentate nitrogen coordination via the pyrazolyl ring was found for the dicoordinate silver(I) complex [L2Ag]NO3·H2O (5). The mol. and crystal structures of 2, 3, 4a, and 5 were detd. by x-ray diffraction.

 

38. Extended lanthanide sandwich complexes

Edelmann, F. T.; Edelmann, A.; Lorenz, V.; Hrib, C. G.

Pacifichem 2010, International Chemical Congress of Pacific Basin Societies, Honolulu, HI, United States, December 15-20, 2010, INOR-730.

This talk intends to highlight our recent achievements in the area of extended lanthanide sandwich complexes contg. bulky cyclooctatetraenyl (= COT) ligands. For example, spontaneous redn. of YbCl3 in the presence of C5Me5- and [C8H5(SiMe3)3]2- (= COT''') afforded the dark blue heterobimetallic ytterbium(II) sandwich complex (DME)2K(×-COT''')Yb(C5Me5) (DME = 1,2-dimethoxyethane), a potential building block for extended heterometallic structures. Reactions of LnCl3 with Li2(COT'') (COT'' = 1,4- bis(trimethylsilyl)cyclooctatetraenyl) gave rise to very different products such as the anionic sandwich complexes [Ln(COT'')2]- or the unprecedented cluster-centered multi- decker sandwich structures [Ln(COT'')]2[Ln2(COT'')2]2Li2(THF)2Cl8. Structural verification of the neutral triple-decker sandwich complexes Ln2(COT'')3, although first reported 12 years ago, remained elusive until very recently a newly developed synthetic route enabled us to det. the mol. structure of Nd2(COT'')3. Our synthetic efforts in this area culminated in the synthesis and structural characterization of the first linear lanthanide tetra-decker sandwich complex. The structure of an unprecedented org./inorg. lanthanide triple-decker as well as attempts to access heterometallic tetra- decker sandwich complexes will also be described.

 

39. Unprecedented Bending and Rearrangement of f-Element Sandwich Complexes Induced by Superbulky Cyclooctatetraenide Ligands

Lorenz, Volker; Schmiege, Benjamin M.; Hrib, Cristian G.; Ziller, Joseph W.; Edelmann, Anja; Blaurock, Steffen; Evans, William J.; Edelmann, Frank T.

J. Am. Chem. Soc. (2011), 133, 1257-1259.

The use of the superbulky cyclooctatetraenide dianion ligand, [1,4-(SiPh3)2C8H6]2- (COT), prepd. from 2,7-bis(triphenylsilyl)cycloocta-1,3,5-triene (I), in organo-f-element chem. leads to unprecedented effects such as the formation significantly bent anionic CeIII sandwich complex, [(COT)2Ce][Li(DME)2], and a novel cerocene formed by sterically induced SiPh3 group migration, [1,3-(SiPh3)2C8H6]2Ce, as well as th example of a bent uranocene, [1,4-(SiPh3)2C8H6]2U. E.g., reaction of I with nBuLi in DME at -10° and then with CeCl3 gave [(COT)2Ce][Li(DME)2]·4(toluene) in 66% yield.

 

40. Disiloxanediolates and metallasilsesquioxanes of the rare earth elements
Lorenz, Volker; Edelmann, Anja; Giebmann, Stephan; Hrib, Cristian G.; Blaurock, Steffen; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2010), 636, 2172-2191.

A review. This research report summarizes recent results in the chem. of lanthanide disiloxanediolates and metallasilsesquioxanes. Both classes of compds. can be regarded as realistic model compds. for silica-supported lanthanide catalysts.

 

41. New lanthanide(III) disiloxanediolates: Syntheses and structures

Lorenz, Volker; Edelmann, Anja; Blaurock, Steffen; Hrib, Cristian; Edelmann, Frank T. Comptes Rendus Chimie (2010), 13, 577-583.

Three new chloro-functionalized lanthanide(III) bis(disiloxanediolate) complexes, [{(Ph2SiO)2O}2{Li(DME)}2]Nd(DME)Cl (3), [{(Ph2SiO)2O}2{Li(THF)2}2]HoCl·2THF (4), and [{(Ph2SiO)2O}2{Li(THF)2}2]ErCl·2THF (5) were prepd. by the treatment of anhyd. lanthanide trichlorides, LnCl3 (Ln = Nd, Ho, Er), with two equiv. of in situ prepd. (Ph2SiOLi)2O (2) (DME = 1,2-dimethoxy-ethane). In a similar manner, the treatment of PrCl3 with 2 equiv of (Ph2SiOLi)2O (2) in the presence of LiN(SiMe3)2 afforded the silylamide-functionalized deriv. [{(Ph2SiO)2O}2{Li(THF)2}2]Pr[N(SiMe3)2] (6). All new compds. were structurally characterized by x-ray diffraction analyses. Compds. 4 and 5 represent a new intermediate structural type of lanthanide bis(disiloxanediolate) between the inorg. metallocenes (Pr, Nd, Sm) and the metallacrowns (Sc, Y).

 

42. The First Linear, Homoleptic Triple-Decker Sandwich Complex of an f-Element: A Molecular Model for Organolanthanide Nanowires

Lorenz, Volker; Blaurock, Steffen; Hrib, Cristian G.; Edelmann, Frank T. Organometallics (2010), 29, 4787-4789.

The first structurally authenticated linear, homoleptic triple-decker sandwich complex of an f-element, (η8-COT'')Nd(μ-η8:η8-COT'')Nd(η8-COT'') (2; COT'' = [C8H6(SiMe3)2-1,4]2- ) has become available through a rather unexpected synthetic pathway. Treatment of [Li(THF)4][Nd(COT'')2] (1) with anhyd. cobalt(II) chloride (molar ratio ∼2:1) in a toluene suspension afforded 2 in 72% isolated yield. The most notable structural feature of 2 is the near-linear arrangement of the COT'' rings with (ring centroid)-Nd-(ring centroid) angles of 176.1 and 175.6°, resp., and a Nd-(ring centroid)-Nd angle of 177.9°, making the title compd. the first true mol. model for lanthanide-based nanowires.

 

43. Encapsulation of cyclooctatetraenyl dianion in an unusual organic/inorganic lanthanide triple-decker sandwich complex

Lorenz, Volker; Blaurock, Steffen; Hrib, Cristian G.; Edelmann, Frank T.

Dalton Trans. (2010), 39, 6629-6631.

Treatment of [(COT)Nd(THF)2(μ-Cl)]2 with dilithium tetraphenyldisiloxanediolate, (LiOSiPh2)2O, in a molar ratio of 1:4 afforded the novel org./inorg. triple-decker complex (μ-η8:η8-COT)[Nd{(Ph2SiO)2O}2{Li(THF)2}{Li(THF)}]2 which was structurally characterized by x-ray diffraction.

 

44. Coupling of silsesquioxane cages in the coordination sphere of erbium

Lorenz, Volker; Blaurock, Steffen; Hrib, Cristian G.; Edelmann, Frank T.

Eur. J. Inorg. Chem. (2010), 2605-2608.

A novel transformation of silsesquioxane cages in the coordination sphere of a lanthanide ion is reported. Reaction of in situ prepd. (c-C6H11)7Si7O9(OLi)3 with anhyd. ErCl3 in thf soln. afforded the large heterometallic (Er/Li) metallasilsesquioxane cluster (c-C6H11)21Si21O36(SiMe3)Er2(thf)2Li4Cl2 (2) in good yield (65%). The mol. structure of 2 comprises several unusual features, including the coupling of two silsesquioxane cages through an -O3Si(c-C6H11)- unit as well as trimethylsilylation of an Si-OH functionality. Due to the presence of 21 cyclohexyl substituents in the periphery of the mol., the large cluster compd. is sol. even in pentane.

 

45. The first heterobimetallic metallasilsesquioxane derivatives of manganese

Lorenz, Volker; Blaurock, Steffen; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2008), 634, 2819-2824.

The reaction of (c-C6H11)7Si7O9(ONa)3, prepd. in situ from (c-C6H11)7Si7O9(OH)3 (1), and MnCl2(THF)2 in THF soln. gave the novel heterobimetallic Mn/Na metallasilsesquioxane complex [(c-C6H11)7Si7O9(O3Mn)Na(Et2O)]2·Et2O (2) which was isolated as colorless crystals in 64% yield. Similar treatment of MnCl2(THF)2 with in situ prepd. (c- C6H11)7Si7O9(OLi)3 afforded the unusual tetramanganese silsesquioxane complex [(c- C6H11)7Si7O9(O3Mn2Br)LiBr(THF)(Et2O)]2 (3) in high yield (81%). Both 2 and 3 were structurally characterized by single-crystal x-ray diffraction.

 

46. Siloxanediolates of the rare earth elements - an eight-membered inorganic ring system containing ytterbium

Giessmann, Stephan; Blaurock, Steffen; Edelmann, Anja; Lorenz, Volker; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2008), 634, 2459-2462.

Treatment of anhyd. YbCl3 with LiN(SiMe3)2 followed by reaction with 1 equiv of 1,1,3,3,5,5-hexaphenyl-1,3,5-trisiloxanediol afforded the 1st mono(trisiloxanediolate) complex of a rare earth element. [Ph2Si(OSiPh2O)2]-Yb(THF)(μ-Cl)3Li2(THF)3 (1) was isolated as colorless crystals in very high yield (93%). A single-crystal x-ray diffraction study confirmed the presence of an eight-membered inorg. ring system contg. Yb. Coordination of one THF ligand and retention of two equivs of LiCl give an "ate" complex.

 

47. 1,2,3-Triphenyl-1,2-dihydroquinoxaline

Edelmann, Frank T.; Blaurock, Steffen; Lorenz, Volker; Fischer, Axel

Acta Cryst., Sect. E: Struct. Rep. Online (2008), 64, o1977.

The title compd., C26H20N2, first reported in 1891, was obtained as a byproduct in the prepn. of benzildianil from benzil and excess aniline. The dihedral angles between the fused benzene ring and the pendant Ph rings are 17.93 (11), 53.18 (10) and 89.08 (12)°. Crystallog. data are given

 

48. Coordination chemistry of acrylamide. 6 Synthesis and coordination compounds of N-pyrazolylpropanamide - a versatile acrylamide-derived ligand

Girma, Kibatu B.; Lorenz, Volker; Blaurock, Steffen; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2008), 634, 267-273.

The syntheses, spectroscopy and single crystal x-ray structures of the multifunctional acrylamide-derived ligand N-pyrazolylpropanamide (= L) (1), and its complexes [L2CuCl2] (2) and [L4Co3Cl6] (3) with copper(II) and cobalt(II) chlorides, resp., are described. The ligand 1 is easily obtained in one step by the reaction of pyrazole with acrylamide in a 1:1 molar ratio in the presence of trimethylbenzylammonium hydroxide as a basic catalyst. The reaction of CuCl2·2H2O with 1 in a 1:2 metal salt:ligand molar ratio in ethanol/-triethylorthoformate soln. gave coordination compd. 2. The crystal structure of 2 contains two seven-membered chelate rings formed by two nitrogen atoms of the pyrazolyl groups and two weakly coordinated carbonyl oxygen atoms of the substituted amide moieties. Two chloride ions in the axial positions complete a distorted octahedral coordination environment around the CuII atom. The reaction of CoCl2·6H2O with 1 in a 1:2 metal salt:ligand molar ratio afforded the unusual zwitterionic complex 3. The crystal structure of 3 contains a central cobalt atom in an octahedral coordination surrounded by four ligands in which two of them act as chelate ligands and the other two, coordinated via the carbonyl oxygen atoms of the amide moieties to this metal center, act as bridging ligands bonded to two CoCl3-units.

 

49. [{μ-Cy8Si8O13}2Ca(DME)Ca(THF)2] - the first metallasilsesquioxane derivative of a heavier alkaline earth metal

Lorenz, Volker; Blaurock, Steffen; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2008), 634, 441-444.

[{μ-Cy8Si8O13}2Ca(DME)Ca(THF)2] (2, Cy = cyclohexyl, DME = dimethoxyethane), the first metallasilsesquioxane deriv. of a heavier alk. earth metal, was prepd. by a reaction of Cy7Si7O9(OH)3 (1) with metallic Ca in liq. ammonia/THF followed by recrystn. from DME. In the reaction ligand rearrangement under formation of the (Cy8Si8O13)2- dianion takes place. In the dinuclear calcium complex 2 the anionic silsesquioxane cages act as bridging ligands. The Ca2+ ions are unsym. coordinated by THF and DME mols.

 

50. [Cp2TiNi(S2N2)2] - the first organometallic derivative of [Ni(S2N2H)2]

Edelmann, Frank T.; Blaurock, Steffen; Lorenz, Volker; Chivers, Tristram

Z. Anorg. Allg. Chem. (2008), 634, 413-415.

The synthesis and structural characterization of the 1st organometallic deriv. of [Ni(S2N2H)2] (1) are reported. Treatment of K2[Ni(S2N2)2] (2) with stoichiometric amts. of [Cp2TiCl2] in boiling toluene afforded black, cryst. [Cp2TiNi(S2N2)2] (3) in 50% yield. According to a single-crystal x-ray diffraction study, the novel heterobimetallic complex 3 comprises a nearly planar TiNi(S2N2)2 arrangement. The Ti···Ni sepn. in 3 is 2.8348(5) Å, a value that is typical for bridged early-late heterobimetallic complexes.

 

51. Coordination chemistry of acrylamide 6: Formation and structural characterization of [Fe(O-OC(NH2)CHCH2)6][Fe2OCl6]

Girma, Kibatu B.; Lorenz, Volker; Blaurock, Steffen; Edelmann, Frank T.

Inorg. Chim. Acta (2008), 361, 346-348.

The new acrylamide Fe(II)/Fe(III) complex [Fe(O-OC(NH2)CH=CH2)6][Fe2OCl6] (1) was obtained by the reaction of a mixt. of anhyd. FeCl2 and anhyd. FeCl3 with acrylamide (molar ratio 1:2:6) in 98% pure com. nitromethane under N atm. According to an x-ray structural anal., the acrylamide ligands in the cation are coordinated via the amide-O atoms. The formation of the (μ-oxo)bis[trichloroferrate(III)]2- anion presumably resulted from partial hydrolysis of FeCl3 or [FeCl4]- by small amts. of H2O in the nitromethane and/or by the nitromethane itself.

 

52. A Surprising Solvent Effect on the Crystal Structure of an Anionic Lanthanide Sandwich Complex

Lorenz, Volker; Edelmann, Anja; Blaurock, Steffen; Freise, Fritjof; Edelmann, Frank T.

Organometallics (2007), 26, 6681-6683.

An unusual solvent effect on the crystn. of an anionic lanthanide sandwich complex was discovered, demonstrating how small changes can make big differences when crystg. organometallic compds. Crystn. of Li(DME)Tb(COT'')2 (1) from toluene gives supramol. [Li(DME)Tb(COT'')2]n (1a), while monomeric Li(DME)Tb(COT'')2 (1b) is formed upon crystn. from pentane, which is intercalated in the crystal structure of the latter.

 

53. Unusual inorganic ring systems of scandium and yttrium containing Group 13 metals: coordination of monomeric Me2InOMe to yttrium

Giessmann, Stephan; Blaurock, Steffen; Lorenz, Volker; Edelmann, Frank T.

Inorg. Chem. (2007), 46, 10956-10958.

Heterobi- and heterotrimetallic indium-yttrium and scandium-lithium-aluminum 1,1,3,3-tetraphenyldisiloxanediol-bridged metallacrown complexes were prepd. by transmetalation of yttrium and scandium 1,1,3,3-tetraphenyldisiloxanediolates with InMe3 and AlMe3, resp. Treatment of the scandium metallacrown complex [{(Ph2SiO)2O}2{Li(DME)}2]ScCl·THF (1) with AlMe3 resulted in an Li-Al exchange reaction and the formation of the heterotrimetallic inorg. ring system [{(Ph2SiO)2O}2{Li(THF)2}AlMe2]ScCl·THF (2). The related yttrium metallacrown [{(Ph2SiO)2O}2{Li(THF)2}2]YCl·THF (3) reacts with InMe3 under the formation of the heterobimetallic Y/In disiloxanediolate complex [{(Ph2SiO)2O}2{InMe2(OMe)}2InMe2]Y (4). In the latter, two monomeric Me2InOMe ligands are stabilized through coordination to yttrium.

 

54. Structural varieties in heterobimetallic lanthanide disiloxanediolates: "inorganic metallocenes" versus in-plane metallacrowns

Giessmann, Stephan; Blaurock, Steffen; Lorenz, Volker; Edelmann, Frank T.

Inorg. Chem. (2007), 46, 10383-10389.

The previously proposed concept of inorg. metallocenes of Group 3 and rare-earth elements was tested by prepg. novel disiloxanediolates with metals displaying different ionic radii. For the smaller Sc and Y, approx. planar arrangements of the disiloxanediolate frameworks with solvent and chloride ligands in trans positions were found. Thus, [{(Ph2SiO)2O}2{Li(DME)}2]ScCl(THF/DME) (2; DME = 1,2-dimethoxyethane) and [{(Ph2SiO)2O}2{Li(THF)2}2]YCl(THF) (3) can be described as heterobimetallic inorg. ring systems or metallacrown complexes with in-plane coordination of the metal. In contrast, out-of-plane geometries with cis coordination of addnl. ligands were identified in the Pr derivs. [{(Ph2SiO)2O}2{Li(THF)2}{Li(THF)}]Pr(μ-Cl)2Li(THF)2 (4) and [{(Ph2SiO)2O}2{Li(DME)}2]PrCl(DME) (5). These compds. can be viewed as analogs of the known metallocene derivs. (C5Me5)2Pr(μ-Cl)2Li(THF)2 and (C5Me5)2PrCl(THF). The mol. structures of 2-5 were detd. by x-ray diffraction.

 

55. [(C5Me5)Yb(μ-η8,η8-COT''')Yb(μ-η8,η8-COT''')Yb(C5Me5)] - a unique tetradecker sandwich complex of a divalent lanthanide

Edelmann, Anja; Blaurock, Steffen; Lorenz, Volker; Hilfert, Liane; Edelmann, Frank T. Angew. Chem., Int. Ed. Engl. (2007), 46, 6732-6734.

The f elements can form well-defined multidecker sandwich complexes as long as a suitable ligand set is chosen. In the case of the title compd. (2), a combination of pentamethylcyclopentadienyl and 1,3,6-tris(trimethylsilyl)cyclooctatetraenyl (COT''') ligands was employed to give a nearly linear stacked Yb3 arrangement. Thus, treating 1.58 mmol YbI2(THF)2 with KC5Me5 in THF, followed by treatment with [K2(DME)2](COT''') in THF gave 64% 2, the structure of which was detd. by x-ray crystallog.

 

56. Unprecedented Examples of Heterobimetallic Cerium(IV) Disiloxanediolates
Giessmann, Stephan; Blaurock, Steffen; Lorenz, Volker; Edelmann, Frank T.

Inorg. Chem. (2007), 46, 8100-8101.

The 1st disiloxanediolate complexes of Ce(IV) are reported. Starting from the readily available precursor (tBuO)3CeIV(NO3)(THF)2 (1), the authors prepd. the novel heterobimetallic compds. [{(Ph2SiO)2O}{K(THF)2}]2Ce(OtBu)2 (2) and [{(Ph2SiO)2O}2{(DME)-KOtBu}{(Ph2SiO2)K}Ce]2 (3) and structurally characterized them by x-ray diffraction.

 

57. A Unique Organolanthanide Cluster Containing Bulky Cyclooctatetraenyl Ligands
Lorenz, Volker; Edelmann, Anja; Blaurock, Steffen; Freise, Fritjof; Edelmann, Frank T. Organometallics (2007), 26, 4708-4710.

The reaction of anhyd. PrCl3 with Li2(COT'') (COT'' = 1,4- bis(trimethylsilyl)cyclooctatetraenyl) in THF soln. afforded in 83% yield an unprecedented cluster-centered Pr/Li multidecker sandwich complex [Pr(COT'')]2[Pr2(COT'')2]2Li2(THF)2Cl8 (1), in which a central cube of eight Cl atoms is capped by two [Pr(COT'')]+ half-sandwich and two [Pr2(COT'')2]2+ sandwich units as well as two [Li(THF)]+ moieties.

 

58. 1.5 s-Butyl 1.5 n-butyl bismuth and 1.5-butyl 1.5-isopropyl bismuth as new liquid bismuth precursors for SBT thin film deposition

Matichyn, S.; Lisker, M.; Silinskas, M.; Lorenz, V.; Edelmann, F. T.; Burte, E. P.

ECS Transactions (2007), 2(7, Fundamental Gas-Phase of Surface Chemistry of Vapor- Phase Materials Processing 3), 43-54.

The authors tested tri-Bu bismuth and 1.5-Bu 1.5-iso-Pr bismuth precursors in an at. vapor deposition (AVD) system for SBT deposition. The Sr0.8-1Bi2-2.4Ta2O9 (SBT) thin films were deposited in a Tricent-CVD reactor (AIXTRON AG) on Ir-coated 150 mm silicon (100) wafers. Strontium bis-pentaethoxymethoxyethoxy tantalate (Sr[Ta(OEt)5(OC2H4OMe)]2) was used as the Sr-Ta source. Growth kinetics and structural and elec. properties of the deposited films were investigated. The deposition rate for both bismuth precursors was almost the same and varied only depending on the deposition temp., pressure, and injection parameters. The cryst. fluorite phase appeared at a higher deposition temp. (470-550°C). The SBT films annealed at 700°C were crystd. to the polycryst. perovskite phase.

 

59. Liquid-delivery MOCVD of SBT thin films using novel bismuth precursors

Silinskas, M.; Lisker, M.; Matichyn, S.; Burte, E.; Hyeon, J.; Lorenz, V.; Edelmann, F. T. Proceedings - Electrochemical Society (2005), 2005-09(EUROCVD-15), 881-888.

Thin films of Bi oxide, Sr tantalate, and strontium bismuth tnatalate (SBT) were deposited by novel liq. Bi precursor: triallylbismuth (Bi(CH2CH:CH2)) and a further Bi alkyl precursors. Strontium bis(pentaethoxy)(methoxyethoxy)tantalate (Sr[Ta(OEt)5(OC2H4OMe)]2, pure or dissolved) was used as Sr-Ta source. The growth rate was ≤10 nm/h for triallylbismuth, ≤1000 nm/h for alkylbismuth, and 10-60 nm/h for Sr[Ta(OEt)5(OC2H4OMe)]2-0.05 mol/l. The difference between the pure and dild. Sr[Ta(OEt)5(OC2H4OMe)]2 precursor was only evident at higher temp. The deposition rate of SBT was slightly lower than the rate of Bi oxide. A decrease of the deposition pressure improved uniformity of the film thickness but reduced the deposition rate of the films. XPS depth profiling indicated more metallic bond characteristics of Ti, Sr, and Bi after ion bombardment. The leakage current for the as-deposited samples was about 10-4 A/cm2 at -0.5 MV/cm, the leakage currents for the samples annealed at 700° and 800° is lowered to 10-6 A/cm2 at -0.5 MV/cm.

 

60. Tributylbismuth as a liquid bismuth precursor in an AVD system for strontium bismuth tantalate thin film deposition

Matichyn, S.; Silinskas, M.; Lisker, M.; Burte, E. P.; Lorenz, V.; Edelmann, F. T. Integrated Ferroelectrics (2006), 84, 189-196.

Tributylbismuth was tested as a Bi source for Sr Bi tantalate (SBT) deposition using at. vapor deposition (AVD) system. The effects of annealing temp. on the structural and elec. properties of deposited films were studied. SBT films annealed at 750° were crystd. in ferroelec. perovskite phase. Ferroelec. hysteresis loops of the SBT films were measured, from which a remnant polarization of 3.5 μC/cm2 and a coercive voltage of 3 V of the crystd. SBT layer were evaluated. SBT thin films annealed at 750° also showed good fatigue properties. Fatigue is ∼4% after 109 cycles.

 

61. Improved process for preparation of mixed trialkylbismuth compounds by Grignard alkylation as bismuth precursors in chemical vapor deposition processes

Edelmann, Frank Thomas; Burte, Edmund; Lorenz, Volker

Ger. (2007), DE 102005037076 B3 20070125

Mixed trialkylbismuth compds. R1R2 2Bi or R1R2R3Bi [1, R1-R3 = (un)branched C1-10 alkyl, preferably at least one R1-R3 = iPr, iBu, secBu, tBu, Me2EtC] in a form of unsepd. mixts., useful as adjustable-vapor pressure bismuth precursors for chem. vapor deposition processes of bismuth-contg. materials and bismuth-contg. layer systems (no data), were prepd. by reaction of mixts. of two or three of the corresponding Grignard reagents RMgX (R = R1-R3; X = Cl, Br, I) with BiCl3 or BiBr3 in org. solvent, preferably in ether solvent at 0-100°, preferably at 20-80° and normal pressure. The prepd. mixed organobismuth compds. 1 are stable,, distillable liqs. featuring desirable volatility for the CVD processes.

 

62. The First Niobasilsesquioxanes

Lorenz, Volker; Blaurock, Steffen; Goerls, Helmar; Edelmann, Frank T.

Organometallics (2006), 25, 5922-5926.

Synthetic routes leading to the 1st polyhedral oligosilsesquioxane derivs. incorporating Nb are reported. Tetrasilanol (c-C6H11)6Si6O7(OH)4 (2) is prepd. in 64% yield in an improved lab.-scale synthesis from hexasiloxane (c-C6H11)6Si6O9 (1). (2) Cleanly reacts with Nb(OEt)5 to afford in 63% yield the dinuclear niobasilsesquioxane [(c- C6H11)6Si6O11NbOEt]2 (3). 3 Slowly converts to the tetranuclear μ-oxo species [(c- C6H11)6Si6O11Nb2(OEt)(μ-OEt)(μ-O)2(THF)]2 (4) in the presence of moisture. A structurally different μ-ethoxy-bridged dinuclear niobasilsesquioxane, [(c- C6H11)7Si7O12Nb(OEt)(μ-OEt)]2 (6), is prepd. in 71% yield from (c-C6H11)7Si7O9(OH)3 (5) and Nb(OEt)5. The mol. structures of 2, 3, 4, and 6 were detd. by x-ray diffraction. The x-ray crystal structure detn. of 2 revealed H bonded dimers in the solid state.

 

63. Coordination chemistry of acrylamide. 5. Crystal structures of complexes of metal(II) perchlorates and tetrafluoroborates with acrylamide

Girma, Kibatu B.; Lorenz, Volker; Blaurock, Steffen; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2006), 632, 1874-1878.

Acrylamide complexes of metal perchlorates and tetrafluoroborates, [M(OC(NH2)CH:CH2)6][X]2 (M = Fe, Co, Ni, Zn; X = ClO4, BF4), were prepd. and characterized using single crystal x-ray diffraction, IR spectroscopy and elemental analyses. The complexes contain metal(II) cations surrounded by an octahedral array of acrylamide ligands accompanied by the anions. The tetrafluoroborate or perchlorate counteranions do not coordinate to the metal atoms or take part in strong secondary interactions such as H bonds with coordinated ligands. Single crystal x-ray structures of these complexes prove that the ligands are coordinated exclusively via the carbonyl O atom. Bonding through the N atom was not obsd. in these complexes.

 

64. Metallasilsesquioxanes

Lorenz, Volker; Edelmann, Frank T.

Adv. Organomet. Chem. (2005), 53, 101-153.

A review of metallasilsesquioxanes of Main Group metals and transition metals and their silsesquioxane precursors.

 

65. Strontium bismuth tantalate thin film deposition by liquid-delivery MOCVD using novel liquid bismuth precursors

Silinskas, M.; Lisker, M.; Matichyn, S.; Burte, E. P.; Hempel, T.; Hyeon, J.; Lorenz, V.; Edelmannn, F. T.

Integrated Ferroelectrics (2006), 79, 195-202.

Novel liq. Bi precursors (triallyl-bismuth, Bi(CH2CH=CH2) and tributylbismuth (BiBu3)) were tested for metalorg. CVD (MOCVD). Strontiumbis-pentaethoxy methoxyethoxy tantalate (Sr[Ta(OEt)5(OC2H4OMe)]2) was used as Sr-Ta source. The growth rates were ≤10 nm/h for triallyl-bismuth and for triphenylbismuth, ≤1000 nm/h for tributylbismuth, and ≤60 nm/h for Sr[Ta(OEt)5(OC2H4OMe)]2. The deposition rate of SBT was always lower than the rate of Bi oxide. A decrease of the deposition pressure improved uniformity of the film thickness but reduced the deposition rate of the films. XPS depth profiling indicated more metallic bond characteristics of Ti, Sr, and Bi after ion bombardment.

 

66. Coordination chemistry of acrylamide 3: Synthesis, crystal structure and IR spectroscopic properties of dichlorotetrakis(O-acrylamide)copper(II), [Cu(O- OC(NH2)CHCH2)4Cl2]

Girma, K. B.; Lorenz, Volker; Blaurock, Steffen; Edelmann, Frank T.

Inorg. Chim. Acta (2006), 359, 364-368.

The mol. structure of the newly prepd. Cu(II) chloride complex with acrylamide (AAm = CH2:CHCONH2), [Cu(AAm)4Cl2], was detd. using x-ray diffraction anal. The complex crystallizes in the cubic space group I4̅3d with a 17.8310(2) Å for Z = 12. The acrylamide mols. bind to the metal center via the carbonyl O atom (Cu-O 1.996 Å). The coordination geometry of the metal center in the complex involves a tetragonally distorted octahedral structure with four O-donor atoms of acrylamide bonded in the equatorial positions and two chlorides in the apical positions. Comparison of crystal structure data of acrylamide and metal acrylamide complexes of those formed with divalent transition metal chlorides was summarized.

 

67. Coordination chemistry of acrylamide 2. Classical complexes of acrylamide with manganese(II), iron(II) and nickel(II) chlorides: syntheses and crystal structures
Girma, K. B.; Lorenz, Volker; Blaurock, Steffen; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2005), 631, 2763-2769.

Metal complexes of manganese(II), iron(II), and nickel(II) chlorides with acrylamide, [M(O-OC(NH2)CH:CH2)4Cl2] (M = Mn, Fe and Ni), were prepd. and characterized by single crystal x-ray diffraction, IR spectroscopy and elemental analyses. The complexes crystallize in the cubic space group, I4̅3d. The coordination geometries of the metal centers in all three complexes involve tetragonally distorted octahedral structures with four O-donor atoms of acrylamide bonded in the equatorial positions and two chlorides in the apical positions.

 

68. Mixed crystalline precursor complexes of the type [Ba(C2H6O2)4][Ti1-xSnx(C2H4O2)3] (x = 0 - 1 ) for BaTi1-xSnxO3 ceramics: Synthesis, structure and calcination

Koeferstein, Roberto; Jaeger, Lothar; Lorenz, Volker; Abicht, Hans-Peter; Woltersdorf, Joerg; Pippel, Eckhard; Goerls, Helmar

Solid State Sci. (2005), 7, 1280-1288.

The synthesis of [Ba(C2H6O2)4][Ti(C2H4O2)3], its crystal structure and thermal decompn. is described. This 1,2-ethanediolato complex forms with the isotypic tin compd. [Ba(C2H6O2)4][Sn(C2H4O2)3] solid solns. [Ba(C2H6O2)4][Ti1-xSnx(C2H4O2)3] in any ratio. Corresponding mixed cryst. samples are suitable precursor complexes for BaTi1-xSnxO3 ceramics with the feature of a heavy element distribution in mol. scale matching the element distribution of the final ceramics.

 

69. Coordination chemistry of acrylamide. 4. Crystal structures and IR spectroscopic properties of acrylamide complexes with CoII, NiII, and ZnII nitrates

Girma, K. B.; Lorenz, Volker; Blaurock, Steffen; Edelmann, Frank T.

Z. Anorg. und Allg. Chem. (2005), 631, 1843-1848.

Acrylamide complexes of metal nitrates, [M(O-OC(NH2)CH:CH2)n(H2O)m][NO3]2 (M = Co (1), Ni (2) (n = 6 and m = 0) and Zn (3, n = 4 and m = 2)), were prepd. and structures were detd. by using single crystal x-ray diffraction anal. All complexes crystallize in the triclinic space group P1̅. The structures of 1 and 2 represent octahedral species [M(AAm)6]2+ (AAm = O-OC(NH2)CH:CH2 and M = Co or Ni) and uncoordinated nitrate ions. The structure of 3 involves the octahedral cation [Zn(AAm)4(H2O)2]2+ in which the Zn2+ environment includes oxygen atoms of four acrylamide and two water mols. that are stabilized using ionic nitrate ions. The observations of the solid-state IR spectroscopic vibrational frequencies of these acrylamide complexes are in agreement with the crystal structures.

 

70. Dielectric and electromechanical characterization of fine-grain BaTi0.95Sn0.05O3 ceramics sintered from glycolate-precursor powder

Geske, Ludwig; Lorenz, Volker; Mueller, Thomas; Jaeger, Lothar; Beige, Horst; Abicht, Hans-Peter; Mueller, Volkmar

J. Eur. Ceram. Soc. (2005), 25, 2537-2542.

Nanocryst. BaTi0.95Sn0.05O3 (BTS-5) powder was synthesized from [Ba(C2H6O2)4][Ti(C2H4O2)3] and [Ba(C2H6O2)4][Sn(C2H4O2)3] glycolate precursors, and used to sinter fine-grain BTS-5 ceramics. We compare sintering behavior, microstructure as well as dielec. and electromech. properties of the advanced ceramics with ceramics sintered from classical mixed oxide powder.

 

71. Coordination chemistry of acrylamide: 1. Cobalt(II) chloride complexes with acrylamide - Synthesis and crystal structures

Girma, K. B.; Lorenz, Volker; Blaurock, Steffen; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2005), 631, 1419-1422.

The mol. structures of blue dichlorotetrakis(acrylamide)cobalt(II), [Co{OC(NH2)CH:CH2}4Cl2] (1) and pink hexakis(acrylamide)cobalt(II) tetrachlorocobaltate(II), [Co{OC(NH2)CH:CH2}6][CoCl4] (2), prepd. and characterized by single x-ray diffraction, IR spectroscopy and elemental analyses, are described. The coordination of CoII in 1 involves a tetragonally distorted octahedral structure with four O-donor atoms of acrylamide in the equatorial positions and two chloride ions in the apical positions. The 2nd complex 2 in ionic form contains CoII cations surrounded by an octahedral array of O-coordinated acrylamide ligands, accompanied by a [CoCl4]2- anion.

 

72. [Ba2(C2H6O2)4][Ge2(C2H4O2)6]·2.5C2H6O2 - an ethanediolato complex of germanium. Synthesis, thermal decomposition and crystal structure

Jaeger, Lothar; Lorenz, Volker; Wagner, Christoph; Müller, Thomas; Abicht, Hans-Peter Z. Kristallogr. (2005), 220, 183-187.

[Ba2(C2H6O2)4][Ge2(C2H4O2)6]·2.5C2H6O2 (3a) is isolated from the reaction of GeO2·aq with Ba(OH)2·8H2O in glycol (1,2-ethanediol). 3A crystallizes in the space group P1̅ with a 10.324(2), b 13.932(3), c 15.800(3) Å, α 102.86(2), β 91.33, γ 109.47°. With increasing temp. 3a loses glycol and forms step by step [Ba(C2H6O2)2][Ge(C2H4O2)3] (3b), Ba[Ge(C2H4O2)3] (3c) and finally hexagonal BaGeO3 (4).

 

73. Coordination chemistry of acrylamide

Girma, K. B.; Lorenz, Volker; Blaurock, Steffen; Edelmann, Frank T.

Coord. Chem. Rev. (2005), 249, 1283-1293.

A review. This review provides a literature survey of the coordination chem. of acrylamide, CH2:CHC(O)NH2 (also known as 2-propenamide, AAm), with a variety of transition metals. First, a general overview of the structure and possible modes of coordination of acrylamide are discussed. This is followed by a summary of the published data on the syntheses and structures of acrylamide complexes. Despite the potential versatility of acrylamide as a ligand, only few complexes that coordinate exclusively through the carbonyl oxygen, [Co(AAm)4(H2O)2](NO3)2, [Cu(AAm)4(NO3)2], [Co(AAm)4Cl2], and [Co(AAm)6][CoCl4] were fully characterized by spectroscopic and x- ray diffraction studies. Finally, some reactions involving acrylamide or acrylamide- based ligands coordinated with less acidic biol. relevant transition metals are considered to form a notion of the potential role of such interactions in acrylamide reactivity in biol. systems. With regard to acrylamide in food and its health effects, the soln. and solid-state chem. of acrylamide or acrylamide-based ligands (metabolites) with less acidic biol. relevant metal ions may be of a great relevance in elucidating the mechanism of acrylamide metab. and its health effects.

 

74. Between Enamide and Azaallyl Structures: Novel Flexible N-Chelate Ligands in the Lanthanide Chemistry

Lorenz, Volker; Görls, Helmar; Thiele, Sven K.-H.; Scholz, Joachim

Organometallics (2005), 24, 797-800.

Novel types of hexa-1,5-diene-1,6-diamide neodymium complexes were prepd. from the corresponding neodymium bromide NdBr3(THF)3.5 with the appropriate dilithium hexa-1,5-diene-1,6-diamide reagent. The mol. structures of the new complexes revealed that the chelating hexa-1,5-diene-1,6-diamide can be bound either as an enamide or as an azaallyl-type ligand. The prepd. complexes were tested as catalysts for 1,3-butadiene polymn.

 

75. Fully metalated silsesquioxanes: Building blocks for the construction of catalyst models

Lorenz, Volker; Giessmann, Stephan; Gun'ko, Yurii K.; Fischer, Axel K.; Gilje, John W.; Edelmann, Frank T.

Angew. Chem., Int. Ed. Engl. (2004), 43, 4603-4606.

Versatile building blocks for the construction of mol. models for heterogeneous catalysts are readily available in high yields as fully metalated silsesquioxane derivs., such as [(Cy7Si7O12)2Li6(THF)4]·THF, [(Cy7Si7O12)2Li2(MeCOMe)2Zr] and [(Cy7Si7O12)2Li4Yb(N(SiMe3)2)] (Cy = cyclohexyl) by using alkali-metal silylamides (here, Li(N(SiMe3)2)) as deprotonating agents. All three complexes were characterized spectroscopically and by x-ray crystallog.

 

76. Dimeric silsesquioxanes and metallasilsesquioxanes - En route to large, well-defined Si-O-assemblies

Lorenz, Volker; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2004), 630, 1147-1157.

A review. Recent advances in the chem. of dimeric silsesquioxanes and metallasilsesquioxanes are reviewed. The no. of metal-free silsesquioxane dimers is still quite limited, although some promising synthetic routes have already been developed. In contrast, metallasilsesquioxanes contg. two silsesquioxane ligands are known with numerous metals, including Li, K, Be, Al, In, Sc, Sm, Yb, U, Ti, Zr, VC, Ta, Cr, and Cu. A major breakthrough in this chem. was the successful synthesis of fully metalated silsesquioxane precursors such as (Cy7Si7O12)2Li6(THF)2.

 

77. Syntheses and characteristics of heterobimetallic organic derivatives of silicon with the 2-(dimethylaminomethyl)ferrocenyl ligand FcN (η5-C5H5)Fe[η5-C5H3(CH2NMe2)]-
Jacob, Klaus; Görls, Helmar; Lorenz, Volker

Z. Anorg. Allg. Chem. (2004), 630, 752-755.

The heterobimetallic organolithium, [2-[(dimethylamino)methyl]ferrocenyl]lithium , LiFcN, reacts with SiCl4 to give 48% of the heterobimetallic organosilicon compd. [(FcN)3SiCl] (1). The heterobimetallic organosilanol [(FcN)3SiOH] (2) is formed in 38% yield by hydrolysis of 1. A detailed characterization of compds. 1 and 2 was carried out by NMR and mass spectrometry and also by x-ray crystallog. anal. of 2 (space group P1̅, Z = 4, wR2 = 0.3423).

 

78. Thermogravimetric, cyclovoltammetric, and Moessbauer spectroscopic investigations on heterobimetallic organo derivatives of silicon and germanium with the 2-(dimethylaminomethyl)ferrocenyl ligand (η5-C5H5)Fe[η5-C5H3(CH2NMe2)], FcN

Jacob, Klaus; Zanello, Piero; Fontani, Marco; Pietzsch, Claus; Bohmhammel, Klaus; Lorenz, Volker

Z. Anorg. Allg. Chem. (2003), 629, 2004-2012.

The thermal decompn. of the cyclotetrametalloxanetetrols [(FcN)4M4O4(OH)4] (M = Si (1), Ge (2)) as well as the cyclohexagermoxanediol [(FcN)6Ge6O8(OH)2] (3) takes place in three defined steps. For the monomer silanediol [(FcN)2Si(OH)2] (4), only two such steps are obsd. Cyclovoltammetric oxidn. of the metalloxanes 1-2 occurs in two two- electron steps and two subsequent one-electron transitions. The oxidn. of 3 occurs in a four-electron process followed by a two-electron transition. Silanediol 4 is oxidized via two one-electron transitions. Oxidn. of the educt [FcNGeCl3] (5) occurs in a one- electron step. Temp.-dependent 57Fe-Moessbauer-measurements confirm intervalent electron transitions in 1-5, as well as the chelate structure in 5.

 

79. Monoazadiene complexes of early transition metals: Part 4. Reduction of a 1-aza-1,3- diene to a 1-azabut-2-ene-1,4-diyl dianion: An unusual reaction course

Lorenz, Volker; Görls, Helmar; Scholz, Joachim

Angew. Chem., Int. Ed. Engl. (2003), 42, 2253-2257.

Lithium metal redn. of the 1-aza-1,3-diene, 2-methyl-3-phenylpropenal N- isopropylimine (1) afforded unexpected result, dilithium 2,5-dimethyl-3,4- diphenylhexa-1,5-dien-1,6-diamide complex 2, which probably forms by dimerization of the initially generated radical anion of 1. However, the new C-C bond of 2 is further reductively cleaved by lithium, which leads to the formation of the dark red (N- isopropyl-3-methyl-4-phenyl-1-azabut-2-en-1,4-diyl)dilithium-tris(tetrahydrofuran) complex 3.

 

80. Silsesquioxane chemistry. 13. Synthesis and structural characterization of a dimeric indasilsesquioxane stabilized by intramolecular hydrogen bonding

Lorenz, Volker; Fischer, Axel; Jacob, Klaus; Edelmann, Frank T.

Inorg. Chem. Commun. (2003), 6, 795-798.

The compd. [Cy7Si7O12(OH)InMe]2 (2, Cy = cyclohexyl) was prepd. in high yield (84%) by reacting the incompletely condensed silsesquioxane deriv. Cy7Si7O9(OH)3 (1) with trimethylindium in toluene soln. at 20 °C. The mol. structure of 2 has been detd. by X- ray diffraction. In the solid state, self-assembly leads to the formation of a dimeric indasilsesquioxane mol. which is stabilized by two intramol. hydrogen bonds

 

81. Metalloxanes of silicon and germanium with the 2-(dimethylaminomethyl)- ferrocenyl ligand (FcN). Synthesis and molecular structures of (FcN)4M4O4(OH)4 (M = Si, Ge), FcN6Ge6O8(OH)2 and of (FcN)2Si(OH)2

Lorenz, Volker; Jacob, Klaus; Wagner, Christoph; Görls, Helmer

Z. Anorg. Allg. Chem. (2002), 628, 2855-2861.

(FcN)4Si4O4(OH)4.H2O (2) and (FcN)4Ge4O4(OH)4.H2O (3) [FcN = 2- (dimethylaminomethyl)ferrocenyl] were prepd. by hydrolysis of FcNSiCl3 or FcNGeCl3 (1) in Et2O in the presence of (NH4)2CO3. The tricyclic compd. (FcN)6Ge6O8(OH)2 (4) is formed after treatment of the hydrolysis soln. of FcNGeCl3 with CaH2. (FcN)2Si(OH)2 (5) was synthesized by hydrolysis of (FcN)2SiCl2 under similar conditions. Compds. 1-5 were obtained as yellow-orange crystals. The mol. structures of 1-5 were detd. by x- ray diffraction. Compds. 2 and 3 consist of 8-membered Si-O/Ge-O rings with one OH and one FcN-ligand on each Si or Ge atom, resp. Compd. 4 represents a stair-like tricyclic Ge-O structure whereas 5 is a discrete silanediol. Compds. 2-5 have O-H···N H- bridges of the OH groups to the N atoms of the FcN substituents.

 

82. Silsesquioxane chemistry. Part 10. Silsesquioxane silanolate complexes of samarium and scandium

Lorenz, Volker; Fischer, Axel; Edelmann, Frank T.

J. Organomet. Chem. (2002), 647, 245-249.

Two novel complexes of Sm and Sc contg. silsesquioxane silanolate ligands were synthesized and structurally characterized by x-ray diffraction. Yellow (C5Me5)2Sm[μ- Cy7Si8O12O]2Li(THF) (1, Cy = c-C6H11), the 1st organolanthanide silsesquioxane complex, was obtained in 68% yield by treatment of the 'ate'-complex (C5Me5)2Sm(μ-Cl)2Li(THF)2 with Cy7Si8O12OLi in a molar ratio of 1:2. In heterobimetallic 1, Sm and Li are bridged by two silsesquioxane silanolate ligands. Reaction of (C5Me5)Sc(acac)2 with two equiv Cy7Si8O12OH leads to the closely related binuclear Sc complex [Sc(acac)2(μ- Cy7Si8O12O)]2 (2) in 61% yield.

 

83. Silsesquioxane chemistry Part 5. New silyl-functionalized silsesquioxanes

Lorenz, V.; Spoida, M.; Fischer, A.; Edelmann, F. T.

J. Organomet Chem. (2001), 625, 1-6.

Treatment of Cy7Si7O9(OH)3 (1) with Me2SiCl2 (molar ratio 2:3) in the presence of triethylamine affords the Me2Si-bridged bis(silsesquioxane) deriv. Me2Si[Cy7Si7O10(O2SiMe2)]2 (5). The novel silsesquioxane vinyl monomer Cy7Si7O9(OSiMe2CH:CH2)3 (7) has been synthesized by reacting in situ generated Cy7Si7O9(OLi)3 with three equiv. of Me2SiCl(CH:CH2). The mol. structures of 5 and 7 as well as that of the known silyl-functionalized silsesquioxane precursor Cy7Si7O9(OH)(OSiMe3)2 have been detd. by x-ray diffraction.

 

84. f-element disiloxanediolates: novel Si-O-based inorganic heterocycles

Lorenz, Volker; Fischer, Axel; Jacob, Klaus; Brüser, Wolfgang; Edelmann, Frank T. Chem.: Eur. J. (2001), 7, 848-857.

The prepn. and structural characterization of scandium and f-element complexes derived from the disiloxanediolate dianion, [(Ph2SiO)2O]2-, are reported. Reactions of in situ prepd. Ln[N(SiMe3)2]3 (Ln = Eu, Sm, Gd) with (Ph2SiOH)2O in different stoichiometries afforded the lanthanide disiloxanediolates [Eu{[(Ph2SiO)2O]Li(Et2O)}3] (1), [{{(Ph2SiO)2O}Li(dme)}2SmCl(dme)] (2), and [{{(Ph2SiO)2O}Li(THF)2}2GdN(SiMe3)2] (3). In situ formed (Ph2SiOLi)2O reacted with anhyd. NdBr3 (molar ratio 3:1) to give polymeric [{Nd{(Ph2SiO)2O}3{μ-Li(THF)}2{μ2-LiBrLi(THF)(Et2O)}}n] (4). Treatment of 3 with Ph2Si(OH)2 in the presence of acetonitrile yielded the dilithium trisiloxanediolate deriv. [{Ph2Si(OSiPh2-O)2}{Li(MeCN)}2]2 (5), which according to an x-ray anal. displays an Li4O4 heterocubane structure. The trinuclear scandium complex [{{(Ph2SiO)2O}Sc(acac)2}2Sc(acac)] (6) was obtained by reaction of [(C5Me5)Sc(acac)2] (C5Me5 = η5-pentamethylcyclopentadienyl) with (Ph2SiOH)2O in a 3:2 molar ratio. Selective formation of the colorless uranium(VI) deriv. [U{Ph2Si(OSiPh2O)2}2{(Ph2SiO)2O}] (7) was obsd. when uranocene, U(η8-C8H8)2, was allowed to react with (Ph2SiOH)2O. An x-ray diffraction study of the solvated deriv. [U{Ph2Si(OSiPh2O)2}2{(Ph2SiO)2O}]·Et2O·TMEDA (TMEDA = N,N,N',N'- tetramethylethylenediamine) (7a) revealed both the original [(Ph2SiO)2O]2- dianion as well as the ring-enlarged [Ph2Si(OSiPh2O)2]2- ligand in the same mol.

 

85. Lanthanides and actinides: annual survey of their organometallic chemistry covering the year 1996

Edelmann, Frank T.; Lorenz, Volker

Coord. Chem. Rev. (2000), 209, 99-160.

A review with 89 refs. covering lanthanide and actinide complexes and their use in org. synthesis and as catalysts.

 

86. Disiloxanediolates and polyhedral metallasilsesquioxanes of the early transition metals and f-elements

Lorenz, Volker; Fischer, Axel; Giessmann, Stephan; Gilje, John W.; Gun'ko, Yurii; Jacob, Klaus; Edelmann, Frank T.

Coord. Chem. Rev. (2000), 206-207, 321-368.

Two modern areas of metallasiloxane chem. are reviewed with over 120 refs. The 1st part deals with the prepn. and structural characterization of the 1st f-element compds. derived from tetraphenyldisiloxanediol. In the 2nd part recent developments in the chem. of polyhedral metallasilsesquioxanes are surveyed, with special emphasis being placed on early transition metal and f-element derivs. Also highlighted are applications of these species in catalysis research

 

87. Silsesquioxane chemistry. Part VIII. First incorporation of a late transition metal into a silsesquioxane cage: synthesis and structural characterization of Cy7Si7O12Fe(tmeda)

Lorenz, Volker; Fischer, Axel; Edelmann, Frank T.

Z. Anorg. Allg. Chem. (2000), 626, 1728-1730.

Cy7Si7O12Fe(tmeda) [I: Cy = cyclohexyl, tmeda = Me2N(CH2)2NMe2] was prepd. by reaction of in-situ generated Cy7Si7O9(OLi)3 with anhyd. FeCl3 followed by treatment with tmeda. Pale yellow cryst. I represents an example of metallasilsesquioxane in which a late transition metal is incorporated into a silsesquioxane cage. The compd. crystallizes as discrete monomers in which the coordination sphere around Fe is satd. by addn. of a chelating tmeda ligand [monoclinic space group Cc, Z = 4, lattice dimensions at -100°: a 2469.0(2), b 1529.9(2), c 1010.4(2) pm, β 116.68(1)°, R = 0.052].

 

88. Silsesquioxane chemistry, Part 6. The first beryllium silsesquioxane: synthesis and structure of [Cy7Si7O12BeLi]2·2THF

Lorenz, Volker; Fischer, Axel; Edelmann, Frank T.

Inorg. Chem. Commun. (2000), 3, 292-295.

[Cy7Si7O12BeLi]2·2THF (3) was prepd. in high yield by reacting in situ prepd. Cy7Si7O9(OLi)3 (2) with anhyd. BeCl2 in THF at 20°. The mol. structure of 3 was detd. by x-ray diffraction (3·0.5C6H14: monoclinic, space group P21, R1 = 0.078) and is the 1st structurally characterized silsesquioxane deriv. of beryllium. In the solid state, self- assembly gives a dimeric mol.

 

89. Silsesquioxane chemistry II. Tin(IV) and hafnium(IV) compounds of silsesquioxanes
Gun'ko, Yurii K.; Nagy, Laszlo; Brüser, Wolfgang; Lorenz, Volker; Fischer, Axel; Giessmann, Stephan; Edelmann, Frank T.; Jacob, Klaus; Vertes, Attila

Monatsh. Chem. (1999), 130, 45-54.

Four complexes of silsesquioxanes with di- and triorganotin(IV) cations were prepd. Their compn. was detd. by std. anal. and spectroscopic methods. Complexes contg. an organotin(IV) moiety and the ligand in a 1:1 ratio are formed. FTIR spectra are consistent with the presence of Sn-O vibrations in the compds. The structure of the complexes is discussed from Mossbauer and multinuclear (1H,13C,119Sn, 29Si) NMR spectroscopy. Comparison of the exptl. quadrupole splitting (QS) with that calcd. from the partial quadrupole splitting (PQS) concept revealed that the complexes formed with dialkyltin(IV) cations as well as the trialkyl derivs. have a regular tetrahedral structure. New organohafnium silsesquioxane [R7Si7O12Hf(C5Me5)] (R = cyclohexyl) (I), was prepd. by treatment of [R7Si7O9(OH)3] with (C5Me5)HfMe3 under elimination of CH4. The mol. structure of I was detd. by x-ray crystallog.

 

90. Si-O-based inorganic ring systems containing f-elements: structural characterization of novel siloxanediolates of the lanthanides and actinides

Lorenz, Volker; Fischer, Axel; Brüser, Wolfgang; Edelmann, Frank T.; Jacob, Klaus; Gelbrich, Thomas; Jones, Peter G.

Chemical Communications (1998), 2217-2218.

Depending on the reaction conditions and the ionic radius of the lanthanide ion, tetraphenyldisiloxanediol, (Ph2SiOH)2O, reacts with [Ln{N(SiMe3)2}3{LiCl(THF)3}3] (Ln = Eu, Gd, Sm) to afford novel heterometallic rare earth disiloxanediolates [Eu{(Ph2SiO)2O}3{Li(OEt2)}3] (1), [Gd{(Ph2SiO)2O}2{N(SiMe3)2}{Li(THF)2}2] (2) and [Sm{(Ph2SiO)2O}2ClLi2(DME)3] (3). 2 And 3 can be regarded as „inorg. lanthanide metallocenes“. A ring expanded uranium(VI) deriv., [U{Ph2Si(OSiPh2O)2}2{(Ph2SiO)2O}] (4), is formed upon treatment of uranocene, [U(η8-C8H8)2], with (Ph2SiOH)2O. 1-4 Were characterized by x-ray crystallog. (1: triclinic, space group P1̅, R1 = 0.0394; 2: monoclinic, space group C2/c, R1 = 0.0295; 3: monoclinic, space group P21/c, R1 = 0.0564; 4: monoclinic, space group Cc, R1 = 0.0258).

 

91. 1,2-N,N-dimethylaminomethylferrocenyl as a ligand towards silicon

Palitzsch, Wolfram; Pietzsch, Claus; Jacob, Klaus; Edelmann, Frank T.; Gelbrich, Thomas; Lorenz, Volker; Puttnat, Mark; Roewer, Gerhard

J. Organomet. Chem. (1998), 554, 139-146.

The restudy of reactions of [2-(dimethylaminomethyl)ferrocenyl]lithium (1), (FcN)Li, with SiCl4 or Me3SiCl gave (FcN)SiCl3 (2) and (FcN)SiMe3 (3), resp.; 2 is an orange-red solid, but previously was reported as a red liq. The structure of 2 was detd. by x-ray structure anal. The reaction of 2 with NaOCHMe2 yields the novel compd. (FcN)Si(OCHMe2)3 (4) which was subjected to x-ray diffraction anal. as its hydrochloride 4 HCl (5). Treating 1 with Cl(SiMe2)6Cl gave 82% (FcN)(SiMe2)6(FcN) (6).

 

92. [Be(dad)2]: synthesis and structure of diazabutadiene beryllium complexes

Thiele, Karl-Heinz; Lorenz, Volker; Thiele, Gerhard; Zoennchen, Peter; Scholz, Joachim Angew. Chem. (1994), 106, 1461-3.

Treatment of BeCl2 with 1,4-bis(4-methylphenyl)-2,3-diphenyl-1,3-diazabutadiene (dad) in toluene in the presence of Na gave [Be(dad)2] (I). I reacted with THF to give [Be(dad)(THF)]2. I is monoclinic, space group P21/c, Z = 4, R = 0.086, Rw = 0.083.

 

93. Syntheses and crystal structures of diazadiene complexes of the alkaline earth metals

Lorenz, Volker; Neumüller, Bernhard; Thiele, Karl-Heinz

Z. Naturforsch., B: Chem. Sci. (1995), 50, 71-75.

[Ca(NRCPh:CPh:NR-N,N')(DME)2] (1; (R = C6H4-4-Me)) was prepd. by reaction of Ca with NR:CPhCPh:NR in DME soln. The compd. forms orange, moisture sensitive crystals, which were characterized by an x-ray structure detn. [space group orthorhombic, P212121, Z = 4, 4634 obsd. unique reflections, R = 0.046, at -70° a 1340.2(3), b 1528.19(3), c 1609.1(3) pm]. The Ca atom is coordinated by the four O atoms of two chelating DME mols. and two N atoms of the diazadiene ligand, bonded in its enediamide form. [Ba2(DME)3(NPhCPh:CPhNPh)2·DME] (3) was obtained from Ba metal and NPh:CPhCPh:NPh in DME soln. as red crystals [space group monoclinic, P21/c, Z = 4, 4000 obsd. unique reflections, R = 0.166, at -70° a 1704.5(3), b 1786.1(4), c 2177.4(4) pm, β 105.98(3)°]. The two Ba atoms are bridged by two differently bonded diazadiene ligands (μ2-N,N';μ-N,σ-N'). Addnl., one of the Ba atoms is coordinated to two DME mols. and the other one to only one of the ether mols. A further DME mol. is a constituent of the crystal lattice.

 

94. Synthesis, properties and crystal structures of magnesium diazadiene complexes
Lorenz, V.; Thiele, K.-H.; Neumüller, B

Z. Anorg. Allg. Chem. (1994), 620, 691-696.

Reactions of RN:CPhCPh:NR (DAD; R = Ph, C6H4-4-Me, C6H4-4-OMe) with Mg in dimethoxyethane lead to [Mg(DAD)2(DME)] (2a-c), with DAD ligands as radical anions. Also, highly reactive complexes [Mg(DAD)(DME)2] (3a-c) were obtained. The crystal structures of 2a, 3a and 3c were detd.

95. Synthesis and properties of bis(tert-butylcyclopentadienyl)magnesium (with a comment on bis(methylcyclopentadienyl)magnesium)

Thiele, K.-H.; Lorenz, V.

Z. Anorg. Allg. Chem. (1990), 591, 195-198.

Bis(tert-butylcyclopentadienyl)magnesium (I) can be obtained easily and in good yields from Et2Mg and tert-butylcyclopentadiene. The synthesis of bis(methylcyclopentadienyl)magnesium (II) was reproduced and differences in bibliog. were cleared up. (MeC5H4)2Mg·TMED (III) was prepd. by the reaction of II with Me2NCH2CH2NMe2, whereas I does not form complexes, apparently for steric reasons. I-III were characterized by their 13C NMR spectra.

 

96. Preparation of N-dichloro-2,4-dioxohexahydro-1,3,5-triazine

Ramhold, Klaus; Moll, Karl Klaus; Schmidt, Harald; Voigt, Hiltrud; Lorenz, Volker; Sommer, Jan; Zimmermann, Gerhard

Ger. (East) (1990), DD 279879 A1 19900620

The title compds., useful as sources of active Cl and for prepn. of the corresponding alkali- and alk. earth metal salts, were prepd. by chlorination of 2,4-dioxohexahydro- 1,3,5-triazine (I) at 273-323K in aq. soln. to a pH of 0.5-2.5. Thus, I in H2O at 293K was treated with Cl with stirring until pH 7 to give 80.2% N-dichloro-I.

 

97. Preparation of N-trichloro-2,4-dioxohexahydro-1,3,5-triazine

Ramhold, Klaus; Moll, Karl Klaus; Schmidt, Harald; Voigt, Hiltrud; Lorenz, Volker; Sommer, Jan; Zimmermann, Gerhard

Ger. (East) (1990), DD 279878 A1 19900620

The title compds., useful as sources of active Cl and for prepn. of the corresponding alkali- and alk. earth metal salts, were prepd. by chlorination of 2,4-dioxohexahydro- 1,3,5-triazine (I) at 273-323K in aq. soln. to a pH of 0.5-2.5. Thus, I in H2O at 293K was treated with Cl with stirring until pH 7 to give 80.2% N-dichloro-I.

 

98. Preparation of triorganostannyl magnesium compounds from triorganostannyl halides, magnesium, and anthracene

Scholz, Joachim; Lorenz, Volker; Thiele, Karl Heinz

Ger. (East) (1989), DD 270713 A1 19890809

(R3Sn)2Mg (I; R = alkyl, aryl, allyl, PhCH2, alkenyl, alkynyl), useful as intermediates for biocides, antioxidants, materials preservatives, etc, were prepd by reaction of R3SnX (X = Cl, Br, iodo) with Mg in ether solvents, preferably THF, in the presence of anthracene. Thus, to a mixt. of iodine-etched Mg and anthracene in THF was added (PhCH2)3SnCl in THF at room temp. The mixt. was stirred 40 h, solvent was removed, and the crude prod. in Et2O was filtered to give a soln of [(PhCH2)3Sn]2Mg in ∼90% yield.