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)(2)C=(tBu)PAu}(2)(g-Cl)]Cl-+(-) (6). In CH2Cl2 solution this mixture was slowly converted into the novel decanuclear complex [Au-8(AuCl)(2){mu(3)-P(tBu)}(2){mu-P(tBu)=C(NMe2)(2)}(6)](4+)(Cl-)(4) (7) featuring six edge-bridging phosphaalkene ligands and two mu(3)-tert-butylphosphanediide ligands. In solution the cluster 7 shows a high order P-31{H-1} NMR spectrum of the [AB(2)C](2) type. According to the X-ray structural analysis the Au-10 framework may be described as a slightly puckered ladder constructed of three quadrangles. The central Au-4 parallelogram is capped on both faces by a pair of [tBuPAuCl] units. (C) Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.