COORDINATION CHEMISTRY OF [C(PPH2)(P(S)PH2)2]- - P-31 NMR OF RHODIUM,IRIDIUM AND PLATINUM COMPLEXES, AND THE CRYSTAL AND MOLECULAR-STRUCTURES OF [RH(COD)(C(PPH2)(P(S)PH2)2-P,S)].CH2CL2 AND [RHI2((T)BUNC)2(C(PPH2)(P(S)PH2)2-P,S)]

Complexes of the anionic ligand, [C(PPh2)(P(S)Ph2)2]-, are readily pre pared under mild conditions by reactions of CH(PPh2)(P(S)Ph2)2, in the presence of base (NHEt2), with chlorobridged complexes, [M2Cl2(cod)2] , M = Rh or Ir, cod = cycloocta-1,5-diene, [Pt2Cl4(PEt3)2], and [Pt2Cl 2(MeOcod)2], MeOcod = 8-methoxy-cyclooct-4-ene-1-yl. The products are [M(cod){C(PPh2)(P(S)Ph2)2-P,S}], [PtCl(PEt3){C(PPh2)(P(S)Ph2)2-P,S}], and [Pt(MeOcod){C(PPh2)(P(S)Ph2)2-P,S}] respectively, and the platinum complexes are both mixtures of the two possible isomers. Subsequent r eactions of [Rh(cod){C(PPh2)(P(S)Ph2)2-P,S}] with (t)BuNC followed by oxidative addition of 12 or benzyl bromide give [Rh(tBuNC)2{C(PPh2)(P( S)Ph2)2-P,S}], and isomeric mixtures of [RhI2(tBuNC)2{C(PPh2)(P(S)Ph2) 2-P,S}] and [RhBr(Bz)(tBuNC)2{C(PPh2)(P(S)Ph2)2-P,S}]. The complexes w ere characterized primarily by P-31 nuclear magnetic resonance (NMR) s tudies and by two crystal structure determinations. Complex 1a, [Rh(co d){C(PPh2)(P(S)Ph2)2-P,S}]. CH2Cl2 crystallized in the P2(1)/c (No. 14 ) space group (Z = 4) with a = 12.294(3), b = 16.063(5), c = 21.384(5) angstrom, beta = 91.60(3)-degrees. Complex 4a(i), [RhI2(tBuNC)2{C(PPh 2)(P(S)Ph2)2-P,S}] crystallizes in the P42(1)BAR/c (No. 114) space gro up (Z = 8) with a = b = 30.174(3), c = 11.317(2) angstrom. Both comple xes contain bidentate P, S bonded ligands with the second P=S group no n-coordinated (''dangling''). In 1a, approximate square planar coordin ation about rhodium is completed by the two double bonds of a cod liga nd, and in 4a(i), the P,S ligand and two cis iodides comprise the equa torial plane of an octahedron which is completed by two (t)BuNC ligand s.