Polyhedral metallaphosphaborane chemistry: the preparation, molecular structure, and nuclear magnetic resonance study of [2-Ph-1,1-(PMe2Ph)2-closo-1,2-PtPB10H10], and some related chemistry
Abstract
The reaction of [B10H11PPh]– with cis-[PtCl2(PMe2Ph)2] in CH2Cl2 yields the new closo twelve-vertex species [(PMe2Ph)2PtB10H10PPh](43% yield) and small quantities of the known nine-vertex arachno-[(PMe2Ph)2PtB8H12]. Crystals of the yellow, air-stable platinaphosphaborane are triclinic, space group P, with a= 961.8(1), b= 1 077.2(2), c= 1 661.4(2) pm, α= 108.67(1), β= 84.63(1), γ= 115.96(1)°, and Z= 2; the final R factor is 0.0212 for 3 702 observed reflections. Diffraction analysis shows that the cluster structure is based on a PtB10P icosahedron with the platinum and phosphorus atoms occupying adjacent positions. The metal-to-cluster bonding is rotationally fluxional with ΔG‡277ca. 58 kJ mol–1. Detailed n.m.r. data for [(PMe2Ph)2PtB10H10PPh], neutral B10H12PPh, and anionic [B10H11PPh]– are presented, compared, and briefly discussed. In contrast to the platinum reaction, reaction of [B10H11PPh]– with [{Rh(η5-C5Me5)Cl2}2] gives the known nido ten-vertex [6-(η5-C5Me5)-nido-6-RhB9H13] and two other products identified as the twelve-vertex closo dimetallaphosphaboranes [7-X-1-Ph-2,3-(η5-C5Me5)-closo-2,3,1 - Rh2PB9H8](X = Cl or H).