COORDINATION CHEMISTRY OF [CH(PPH2)(P(S)PH2)2] - PD, PT, RH, AND IR COMPLEXES, INCLUDING THE CRYSTAL AND MOLECULAR-STRUCTURES OF THE LIGANDAND A TRIPODAL IRRIDIUM COMPLEX, [IR(COD)(CH(PPH2)(P(S)PH2)2-P,S,S)]BF4.CH2CL2

The complex cations, [M(cod){CH(PPh2)(P(S)Ph2)2-P,S,S}]+, M = Ir of Rh , and [MCl(PEt3){CH(PPh2)(P(S)Ph2)2-P,S}]+, M = Pt or Pd, are readily prepared as fluoroborate salts by reactions of the ligand, CH(PPh2)(P( S)Ph2)2, with the chlorobridged complexes, [M2Cl2(cod)2], M = Ir or Rh , cod = cycloocta-1,5-diene, and [M2Cl4(PEt3)2], M = Pt or Pd, under m ild conditions in the presence of NaBF4. Structures are assigned on th e basis of P-31 NMR spectra and, in the case of M = Ir, by X-ray diffr action. The iridium and rhodium complexes contain tripodal eta3-P,S,S Coordinated ligands in contrast to the examples for palladium and plat inum, where the ligands are bidentate eta2-P,S coordinated with the se cond P=S group non-coordinated (''dangling''). In solution at 25-degre es-C, the palladium complex exhibits fluxional behaviour with rapid ex change between the coordinated and ''dangling'' P=S groups. Both plati num and palladium complexes consist mainly of the isomers having the c oordinated P=S group trans to Cl, but small quantities of the other is omer are formed for both metals. The ligand 1, CH(PPh2)(P(S)Ph2)2 crys tallizes in the P2(1)/n (No. 14) space group (Z = 4) with a = 19.867(9 ) angstrom, b = 18.889(7) angstrom, c = 8.828(4) angstrom, beta = 100. 47(5)-degrees and complex 3a, [Ir(cod){CH(PPh2)(P(S)Ph2)2-P,S,S}]BF4 C H2Cl2, in the P-1 (No. 2) space group (Z = 2) with a = 10.899(6) angst rom, b = 21.653(9) angstrom, c = 11.124(5) angstrom, alpha = 85.14(4)- degrees, beta = 111.59(4)-degrees, gamma = 107.93(6). In 3a, iridium i s five-coordinate with an eta3-P,S,S ligand and the two double bonds o f the cod ligand in an irregular geometry. The structural parameters o f the ligand, 1, are changed relatively little by coordination except for a narrowing of the P-C-P angles.