T. M. Zvukova

Aluminium zirconium (+3 and +4) heterometallic hydrido complexes of compositions [(η5-C5H5)2Zr(μ-H)]2(μ-H)AlCl2 and [(η5-C5H5)2ZrH(μ-H)2]3Al

Abstract The Zr(+3) complex of composition [Cp2Zr(μ-H)]2(μ-H)AlCl2 (8) and the Zr(+4) complex of composition [Cp2ZrH(μ-H)2]3Al (9) were isolated from solutions containing zirconocene(+4) and titanocene(+3) compounds and LiAlH4 and characterized by X-ray structural analysis. The basic structural element of 8 is the six-atom ring Zr2AlH3, in which the metal atoms are linked by ordinary hydrogen bridges. In the structure of 9, the Hbendo atom is off the bisector plane of the Cp2Zr fragment and the Al–H distances in the distorted octahedral environment of the aluminium atom are markedly different.

Synthesis and properties of unsolvated bis(cyclopentadienyl)titanium alumohydride. Structure of {[(η5-C5H5)2Ti(μ-H)]2[(η5-C5H5)Ti(μ-H2]Al3(μ-H4)(H)}2·C6H6 a 12-nuclear titanium aluminum hydride complex with a short AlAl bond length, and refined structure of LiAlEt4

Abstract Unsolvated bis(cyclopentadienyl)titanium alumohydride was synthesized by two methods: heterogeneous reaction between (Cp2TiCl)2 and LiAlH4 in toluene and desolvation of Cp2TiAlH4·Et2O in vacuum. In the presence of cyclohexene, Cp2TiAlH4 (1) synthesized by the first method transforms to the known complex [Cp2TiH2Al(H)(C5H4)TiCp(H)]2 (3). The desolvation reaction apparently yields (Cp2TiAlH4)2 (7). In toluene, 7 transforms to a 12-nuclear titanium aluminum hydride complex 8 with short AlAl distances. Complex 1 catalyzes the hydrometallation of ethylene to LiAlEt4 by LiAlH4. Complex 7, unsolvated (Cp2Ti)2AlH4Cl, and (Cp2TiAlH3OEt)2 were tested as catalysts in hexene-1 hydrogenation. Complexes LiAlEt4 and 8 were characterized by X-ray structure analysis.

Transition metal-catalyzed reduction of ZrIV in Cp2ZrX2LiAlH4 and Cp2ZrX2AlH3 (X=Cl, Br, I) systems: structural study of resulting zirconocene(III) aluminum hydride complexes

Abstract The reactions of Cp2ZrX2 (X=Cl, Br, or I) with LiAlH4 or AlH3 in the presence of catalytic amounts of transition metal compounds afford the ZrIIIAl hydride complexes [(Cp2Zr)2(μ-H)](μ-H)2AlX2 (1). Complexes 1 were isolated as crystal solvates with either benzene or benzene and 1,4-dioxane of compositions [(Cp2Zr)2H](H)2AlCl2·C6H6 (2), [(Cp2Zr)2H](H)2AlBr2·C6H6 (3), [(Cp2Zr)2H](H)2AlBr2·C4H8O2·C6H6 (4), and [(Cp2Zr)2H](H)2AlI2·2C6H6 (5) and their structures were studied by X-ray diffraction analysis. Molecules 1 contain the six-membered Zr2AlH3 ring as the central fragment, in which the metal atoms are linked by hydride bridges. The bonding models for 1 are considered and the reasons for stability of 1 are discussed.

Activation of biscyclopentadienyl hydride complexes of titanium and aluminum by NH- and OH-acids in the reactions of hydrogenation of olefins. Crystal and molecular structures of {(η5−Cp)2Ti(μ−H)2AlH]μ−N(C2H4)4O]}2 and [(η5−Cp)2Ti(μ−H(2AlH]2(μ−OC2H4OMe)[(μ1:μ5−C5H4)Ti(μ5−Cp)(μ−H)]2*

The reactions of Cp2TiH2AlH2·Et2O (1) with HN(C2H4)2O, HOC2H4OMe, and water afforded the complexes {Cp2TiH2AlH[μ-N(C2H4)2O]}2 (5), [Cp2TiH2AlH(μ-OC2H4OMe)]2 (6) and (Cp2TiH2AlH)2O (4), respectively. Compounds 5 and 6 are dimers containing bridging Al−E2−Al fragments (E=N or O). Complex 6 in solution converted to the hexanuclear compound [(η5−Cp)2Ti(μ−H(2AlH]2(μ−OC2H4OMe)[(μ1:μ5−C5H4)Ti(μ5−Cp)(μ−H)]2 (8). The structures of complexes 5 and 8 were established by X-ray diffraction analysis. The rates of hydrogenation of hex-1-ene were determined using compounds 4–6 and the complexes [Cp2TiH2AlH(NEt2)]2 and [Cp2TiH2AlH(OEt)]2 as catalysts. The probable mechanism of hydrogenation with the participation of bimetallic hydride complexes of aluminum and titanocene is discussed.

Mechanochemical synthesis of poly(hydridocarbyne)

Poly(hydridocarbyne) was synthesized by the reaction of bromoform and magnesium metal under the mechanochemical activation conditions.

Heterometallic zirconocene(iii) aluminum hydride complex (Cp2ZrH)2HAlCl2·C4H8O2·C6H6

The heterometallic zirconocene(iii) aluminum hydride complex (Cp2ZrH)2HAlCl2·C4H8O2·C6H6 was synthesized by reduction of Cp2ZrCl2 with lithium aluminum hydride in the presence of Cp2TiBH4 and 1,4-dioxane, and its structure was established by X-ray diffraction analysis.

Trimethylaminedichlorogailane (Cl2Ga · NMe3)2 with the Ga-Ga intermetallic bond

The reaction of GaH3 · NMe3 with ClPBut2 in ether occurs through the exchange of ligands followed by reduction of Ga3+ to Gaz+ to yield (GaCl2 · NMe3)2. X-ray structural analysis demonstrated that gallium atoms in this compound form a direct metal-metal bond with the length of 2.421 Å.

Convenient method of synthesis of Cp2TaH3

Modified method for preparation of Cp2TaH3 by reaction between TaCl5, CpNa, and LiAlH4 in dimethoxyethane is described: The yield of Cp2TaH3 is 25 %.