Metallaheteroborane clusters of group 5 transition metals derived from dichalcogenide ligands

Abstract

Treatment of group 5 metal polychlorides such as, [Cp(n)MCl(4-x)] (M = V: n, x = 2; M Nb: n = 1, x = 0), or [Cp*TaCl(4)] (Cp eta(5)-C(5)H(5), Cp* = eta(5)-C(5)Me(5)), with [LiBH(4)center dot THF] followed by thermolysis in the presence of diphenyl diselenide yielded metallaheteroborane clusters [{CpV(mu-SePh)}(2)(mu-Se)], 1 [(CpNb)(2)B(4)H(9)(mu-SePh)], 2 and [(Cp*Ta)(2)B(4)H(11)(SePh)], 3 in modest yields. Compound 1 is an organovanadium selenolato cluster in which two (CpV) moieties bridged by (mu-Se) and two (mu-SePh) ligands. Compound 2 exhibits a bicapped tetrahedral core with one (mu-SePh) ligand. 3 is a tantalahexaborane cluster in which one of the terminal BH protons is substituted by SePh. Compounds 1-3 have been characterized by mass spectrometry, (1)H, (11)B, (13)C NMR spectroscopy, and the geometric structures were unequivocally established by crystallographic analysis of 1-3. (C) 2011 Elsevier B.V. All rights reserved.