GOLD(I)-CLUSTERING AT A PRIMARY ARYLPHOSPHINE WITH BULKY SUBSTITUENTS- [2,4,6-(ME3C)3C6H2P(AUPR3)N](N-2)-BU,PH - N=2-4) COMPLEXES AND CRYSTAL-STRUCTURE OF THE SPECIES WITH N = 3 AND R = PH( (R=T)

Reaction of the primary phosphine ArPH2 (Ar = 2,4,6-(Me3C)3C6H2) with [O(AuL)3]+BF4- reagents yields the trinuclear gold complexes [ArP(AuL) 3]+BF4- (1, L = PPh3; 2, L = P-t-Bu3). A further equivalent of Ph3PAuBF4- can be added to 1 to give [ArP(AuPPh3)4]2+(BF4-)2 (3), whereas fo r 2 the analogous reaction leads to decomposition and formation of [(t -Bu3P)2Au]+BF4-. The neutral intermediate [ArP(AuP-t-Bu3)2] (4) can be obtained in a mixture with 2 upon treatment of ArPH2 with the corresp onding oxonium reagent in a molar ratio of 3:2. All products are color less air-stable solids, which have been characterized by analytical an d spectroscopic data, including an X-ray crystal structure analysis fo r complex 1. Crystals of 1.2CH2Cl2 from CH2Cl2/diethyl ether are tricl inic, P1BAR, with a = 13.520(1) angstrom, b = 13.901(1) angstrom, c = 20.346(2) angstrom, alpha = 85.57(1)-degrees, beta = 87.23(1)-degrees, gamma = 87.23(1)-degrees, V = 3678.2 angstrom3, d(calc) = 1.73 g/cm3, and Z = 2. In the cations of 1, the phosphorus atom is attached to a single gold atom on one side of the ArP plane and to a pair of gold at oms on the other. Clearly, the two ortho t-Bu groups separate the gold atom triad, which is known to form a triangle in the absence of steri c hindrance. In solution, rapid site exchange renders the LAu units NM R-equivalent. A symmetrical structure with two Au2 Pairs at the pentac oordinate phosphorus atom is assigned to complex 3, while for 4 the di gold(I) arylphosphide stoichiometry indicates a three-coordinate phosp horus atom.