PTAU8HG2 AND PTAU7HG2 CLUSTER COMPOUNDS - X-RAY STRUCTURE OF [PT(AUPPH3)8HG2](NO3)4.3CH2CL2

Salts of the cations [Pt(AuPPh3)8(HgX)2]2+, [Pt(AuPPh3)7(AuX)(HgX)2]+, and [Pt(AuPPh3)7(HgX)2]+ (X = NO3, Cl) were prepared by reaction of salts of [Pt(AuPPh3)8]2+ with Hg2X2 or HgX2. The clusters were characterized by 31P and 195NMR spectroscopy, IR spectroscopy, and conductivity measurements. The crystal and molecular structure of [Pt(AuPPh3)8Hg2]- (NO3)4·3CH2Cl2 has been determined by X-ray analysis. The compound crystallizes in space group P4/n, with a = 17.8002 (6) Å, c - 23.0493 (13) Å, V = 7303 Å3, and Z = 2. Cu Kα radiation was used. The residuals are R = 0.039 and Rw = 0.060 for 5936 observed reflections and 371 variables. The metal frame of approximately D4d symmetry is a centered square antiprism, capped on the squares. The Pt is in the center and is surrounded by eight AuPPh3 groups and two Hg atoms, the Au atoms being on the vertices of the squares and the Hg on the caps. The steric strain of the eight PPh3 and two NO3 groups in the periphery of [Pt(AuPPh3)8(HgNO3)2]2+ is relieved by loss of NO3 from both Hg atoms, by substitution of one of the eight Au-bonded PPh3 groups by NO3, or by dissociation of a AuPPh3+ ion. © 1990, American Chemical Society. All rights reserved.