Complexes of the platinum metals part 35. 4,6-Dimethylpyrimidine-2-thiol derivatives of ruthenium, osmium, rhodium and iridium

Reactions of 4,6-dimethylpyrimidine-2-thiol (Me 2 pymSH) and its oxidation product bis(4,6-dimethylpyrimidine-2-yl)disulphide (Me 2 pymSSpymMe 2 ) with a range of platinum metal complexes are described. The chlorohydrides [MHCl(CO)(PPh 3 ) 3 ] (M=Ru, Os) react with Me 2 pymSH in refluxing toluene to afford [RuCl(Me 2 pymS)(CO)(PPh 3 ) 2 ] and [OsH(Me 2 pymS)(CO)(PPh 3 ) 2 ] (two isomers). A similar reaction in cold benzene affords the substitution product [RuH(Cl)(Me 2 pymSH)(CO)(PPh 3 ) 2 ] (two isomers). Reaction of the precursors [MH 2 (CO)(PPh 3 ) 3 ] (MRu, Os) and [Ru(CO) 3 (PPh 3 ) 2 ] in boiling toluene afford [MH(Me 2 pymS)(CO)(PPh 3 ) 2 ] (two isomers) and [Ru(Me 2 pymS) 2 (CO)(PPh 3 )] (two isomers) respectively whilst the reaction of [Ru(CO) 3 (PPh 3 ) 2 ] with Me 2 pymSSpymMe 2 yields a mixture of [Ru(Me 2 pymS) 2 (CO) 2 (PPh 3 )] and [Ru(Me 2 pymS) 2 (CO)(PPh 3 )]. In the presence of the base (NEt 3 ) the dichlorides [MCl 2 (PPh 3 ) 3 ] (M=Ru, Os) react with Me 2 pymSH to afford the bis-chelates [M(Me 2 pymS) 2 (PPh 3 ) 2 ]. Reactions between Me 2 pymSH and the precursors [IrCl(CO)(PPh 3 ) 2 ] and [IrH(CO)(PPh 3 ) 3 ] at ambient temperature or below afford [IrH(Cl)(Me 2 pymS)(CO)(PPh 3 ) 2 ] and [IrH 2 (Me 2 pymS)(CO)(PPh 3 ) 2 ] respectively, the same ligand reacts with [RhCl(PPh 3 ) 3 ] and mer -[IrH 3 (PPh 3 ) 3 ] in refluxing benzene to afford [RhH(Cl)(Me 2 pymS)(PPh 3 ) 2 ], [Rh(Me 2 pymS) 3 (PPh 3 )], and [IrH 2 (Me 2 pymS)(PPh 3 ) 2 ]. The new complexes have been characterised by infrared and NMR [ 1 H, 31 P{ 1 H}] spectroscopy, and shown to contain monodentate (S-bonded) or chelate (N,S-bonded) Me 2 pymS ligands.