Synthesis and Structure of the Decanuclear Gold(I) Cluster Cation [Au8(AuCl)2{μ3-P(tBu)}2{μ-P(tBu)=C(NMe2)2}6]4+ with Bridging Phosphaalkene and Phosphanediide Ligands

Reaction of the inversely polarized phosphaalkene HP=C(NMe2)2 (1) with [AuCl(PPh3)] (2a) in a molar ratio of 2:1 in THF led to the formation of complex [Au{HP=C(NMe2)2}2]Cl (3) as a pale yellow solid. In contrast to this, treatment of 2a with two molar equivalents of tBuP=C(NMe2)2 (4) afforded a mixture of [Au{P(tBu)=C(NMe2)2}2]+Cl− (5) and [{(Me2N)2C=(tBu)PAu}2(μ-Cl)]+Cl− (6). In CH2Cl2 solution this mixture was slowly converted into the novel decanuclear complex [Au8(AuCl)2{μ3-P(tBu)}2{μ-P(tBu)=C(NMe2)2}6]4+(Cl−)4 (7) featuring six edge-bridging phosphaalkene ligands and two μ3-tert-butylphosphanediide ligands. In solution the cluster 7 shows a high order 31P{1H} NMR spectrum of the [AB2C]2 type. According to the X-ray structural analysis the Au10 framework may be described as a slightly puckered ladder constructed of three quadrangles. The central Au4 parallelogram is capped on both faces by a pair of [tBuPAuCl] units. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)