SYNTHESIS OF COMPLEXES OF RE-V, RU-II, OS-II, RH-I, IR-I AND IR-III CRYSTAL AND MOLECULAR-STRUCTURES OF [REO(OH)(SC(6)H(4)SIPH(3)-2)(2)(PPH(3))], [REH4(SC(6)H(4)SIPH(3)-(2))(PPH(3))(3)] AND [IRH(SC(6)H(4)SIPH(3)-2)(2)(PMEPH(2))(3)]

The rhenium(V) precursors [ReOX(3)(PPh(3))(2)] (X = Cl or Br) reacted with 2-triphenylsilylbenzenethiol in methanol in the presence of base to give [ReO(Cl) (SC(6)H(4)SiPh(3)-2)(2)(PPh3)] 1 and [ReO(OH) (SC(6)H (4)SiPh(3)-2)(2)(PPh(3))] 2 respectively. In the presence of NaBH4 and no base the blue thiolate polyhydride [ReH4(SC(6)H(4)SiPh(3)-2)(PPh(3 ))(3)] 3 was formed in high yield. The crystal structures of 2 and 3 w ere determined and showed 2 to be monomeric with distorted trigonal-bi pyramidal geometry and the oxide and hydroxide ligands in equatorial s ites. The thiolate and phosphine ligands of 3 are in a tetrahedral arr ay with the hydride ligands assumed to be in capping sites on the tetr ahedral faces. Reaction of the thiol with [IrCl3(PMePh(2))(3)] in meth anol in the presence of NEt(3) gave [IrH(SC(6)H(4)SiPh(3)-2)(2)(PMePh( 2))(3)] 4 in good yield. Its crystal structure revealed the geometry a bout the Ir to be pseudo-octahedral with mer phosphine ligands and cis thiolates, and the hydride presumed to be in a vacant site trans to a thiolate ligand. The complex [IrCl(CO)(PPh(3))(2)] reacted under simi lar conditions to-give monomeric [Ir(SC(6)H(4)SiPh(3)-2) (CO)(PPh(3))( 2)] 6 whereas [RhCl(CO)(PPh(3))(2)] gave [Rh-2(mu-SC(6)H(4)SiPh(3)-2)( 2)(CO)(2)(PPh(3))(2)] 5; [OsH(Cl)(PPh(3))(3)] gave [OsH(SC(6)H(4)SiPh( 3)-2)(CO)(PPh(3))(3)] 7 whereas [RuH(Cl)(PPh(3))(2)] formed [Ru(SC(6)H (4)SiPh(3)-2)(CO)(PPh(3))(2)] 8. The potentially bidentate thiol SiPh( 2)(C6H4SH-2)(2) gave a series of products with the same precursors whi ch proved difficult to characterise unequivocally in the absence of X- ray structural data. The geometry adopted by the SC(6)H(4)SiPh(3)-2 li gand was analysed in some detail and contrasted with symmetrically 2,6 -disubstituted aromatic thiolates.