Transition metal-catalyzed reduction of Zr-IV in Cp2ZrX2-LiAlH4 and Cp2ZrX2-AlH3 (X = Cl, Br, I) systems: structural study of resulting zirconocene(III) aluminum hydride complexes

摘要

The reactions Of Cp2ZrX2 (X = Cl, Br, or 1) with LiAlH4 or AlH3 in the presence of catalytic amounts of transition metal compounds afford the Zr-III-Al hydride complexes [(Cp2Zr)(2)(mu-H)](mu-H)(2)AlX2 (1). Complexes I were isolated as crystal solvates with either benzene or benzene and 1,4-dioxane of compositions [(Cp2Zr)(2)H](H)(2)AlCl2.C6H6 (2), [(Cp2Zr)(2)H](H)(2)AlBr2.C6H6 (3), [(Cp2Zr)(2)H](H)(2)AlBr2.C4H8O2.C6H6 (4), and [(Cp2Zr)(2)H](H)(2)AlI2.2C(6)H(6) (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. (C) 2003 Elsevier B.V. All rights reserved. [References: 21]