Tris(diphenylthiophosphinoyl)methanide as tripod ligand in rhodium(III), iridium(III) and ruthenium(II) complexes.: Crystal structures of [(η5-C5Me5)Ir{η3-(SPPh2)3C-S,S′,S"}]BF4 and [(η6-MeC6H4Pri)Ru{η3-(SPPh2)3C-S,S′,S"}]BPh4

Reaction of the complex [{(eta(5)-C5Me5)RhCl2}(2)], in CH2Cl2 solution, with AgBF4 (1:2 molar ratio) and (SPPh2)(3)CH leads to the cationic compound [(eta(5)-C5Me5)RhCl{eta(2)-(SPPh2)(2)CH(SPPh2)-S,S'}]BF4 (1) which is deprotonated by thallium(I) pyrazolate affording [(eta(5)-C5Me5)Rh{eta(3)-(SPPh2)(3)C-S,S',S "}]BF4 (2a). The iridium dimer [{(eta(5)-C5Me5)IrCl2}(2)] reacts with silver salts and (SPPh2)(3)CH, in CH2Cl2 or Me2CO, under analogous conditions, affording mixtures of [(eta(5)-C5Me5)IrCl{eta(2)-(SPPh2)(2)CH(SPPh2)-S,S'}](+) and [(eta(5)-C5Me5)Ir{eta(3)-(SPPh2)(3)C-S,S',S "}]A [A = BF4- (3a), PF6- (3b)]. Addition of Et3N to the mixture gives pure complexes 3. The ruthenium complexes [{(eta(6)-arene)RuCl2}(2)] (arene = C6Me6, p-MeC6H4Pri) react with (SPPh2)(3)CH, in the presence of AgA (A = PF6- or BF4-) or Na BPh4, in CH2Cl2 or Me2CO, yielding only the deprotonated complexes [(eta(6)-arene)Ru{eta(3)-(SPPh2)(3)C-S,S',S "}]A [arene = C6Me6, A = BF4; arene = p-MeC6H4Pri, A = BPh4 (4a), PF6 (4b)]. The crystal structures of 3a and 4a were established by X-ray crystallography. Compound 3a crystallizes in the orthorhombic space group Pna2(1), with lattice parameters a = 41.477(6), b = 10.6778(11), c = 20.162(3) Angstrom and Z = 8. Complex 4a crystallizes in a monoclinic lattice, space group P2(1)/n, with a = 20.810(4), b = 12.555(3), c = 23.008(4) Angstrom, beta = 95.82(2)degrees and Z = 4. Both cationic complexes exhibit analogous pseudo-octahedral molecular structures with the anionic (SPPh2)(3)C- ligand bonded via the three sulphur atoms in a tripodal, tridentate fashion. Each metal centre completes its coordination environment with a eta(5)-C5Me5 (3a) or a eta(6)-MeC6H4Pri group (4a). A quite interesting result concerns the non-planarity of the methanide carbon which display P-C-P angles in the range 112.6-114.4(5)degrees in 3a and 111.9-113.6(4)degrees in 4a. The redox chemistry of the complexes was investigated by cyclic voltammetry. The Rh(III) complexes are quasi-reversibly reduced to Rh(I) and the Ir(III) complex is irreversibly reduced to Ir(I) in acetonitrile solutions. The Ru(II) complex undergoes a quasi-reversible reduction to Ru(I) and a reversible oxidation to Ru(III). (C) 1997 Elsevier Science S.A.