Preparation and properties of thiophosphinito-bridged rhodium complexes. Crystal structure of [Rh2(μ-SPPh2)2(COD)2]

Resumen

Reaction of Ph2P(S)H with [M(acac)(diolefin)] (M Rh or Ir) yields [M2(SPPh2)2(diolefin)2] complexes. The reactions of [Rh2(SPPh2)2(COD)2] with t-butylisocyanide, diphosphine, or carbon monoxide have been studied. Several dirhodium(II) complexes have been prepared by a two centre oxidative-addition reaction, or by exchange reactions of [Rh2(O2CMe)4]. A variety of related complexes is discussed. The crystal structure of [Rh2(SPPh2)2(COD)2] has been determined by X-ray diffraction methods. It crystallizes in the triclinic space group P1 with cell dimensions a 12.152(7), b 16.117(8), c 10.805(7) Å, α 90.42(4), β 112.90(3), γ 109.27(3)°, and Z = 2. The structure has been solved from diffractometer data by Patterson and Fourier methods and refined by full-matrix least-squares to R = 0.0405 and Rw = 0.0584 for 5149 observed reflections. In the dimeric complex two SPPh2-ligands bridge the rhodium atoms through their S and P atoms; the coordination around each metal atom is completed by a COD molecule interacting through the two olefinic bonds. The RhRh distance is of 3.770(1) Å, ruling out the possibility of metalmetal interaction. The two Rh(1)S(1)P(2)Rh(2) and Rh(1)P(1)S(2)Rh(2) units are roughly planar, and the six-atom Rh(1)S(1)P(2)Rh(2)S(2)P(1) ring has a boat conformation. © 1988.