Gold–boron chemistry. Part 1. Synthetic, structural, and spectroscopic studies on the compounds [5,6-µ-(AuPR3)-nido-B10H13](R = cyclo-C6H11 or C6H4Me-2)

Abstract

The new Class 2 gold–boron compounds [5,6-µ-(AuPR₃)-nido-B₁₀H₁₃](1a; R = cyclo-C₆H₁₁; 1b, R = C₆H₄Me-2) have been prepared by the reaction between [AuMe(PR₃)] and B₁₀H₁₄ in CH₂Cl₂. Compound (1a) is also afforded by reaction between [AuCl{P(C₆H₁₁)₃}] and [B₁₀H₁₃]^–. The exact mechanism of the first reaction is unclear, but probably proceeds via sequential oxidative addition and reductive elimination. Crystallographic analyses of compounds (1) show the expected decaborane-like geometry. There is some evidence of an intramolecular interaction between Au and the B(9)–H–B(10) bridge system. A thorough n.m.r. study of (1b) was undertaken, including an ¹¹B(COSY) experiment which allowed almost complete assignment of the ten inequivalent B atoms in the molecule.