Efficient Transfer of Either One or Two Dithiolene Ligands from Nickel to Ruthenium: Synthesis and Crystal Structures of [Ru(SCR=CPhS)2(PPh3)] and [RuCl2(SCR=CPhS)(PPh3)2] (R = Ph, H)

High yields of two different types of ruthenium dithiolene complex have been obtained by reactions that involve transfer of the dithiolene ligands from the nickel complexes [Ni(SCR=CPhS)(2)] (R = Ph, H) to [RuCl2(PPh3)(3)]. At room temperature one dithiolene is rapidly transferred to yield [RuCl2(SCR=CPhS)(PPh3)(2)], whereas under thermal conditions (refluxing toluene) two dithiolene ligands are incorporated to give [Ru(SCR=CPhS)(2)(PPh3)]. The crystal structures of the ruthenium bis(dithiolene) complexes indicate that the dithiolene ligands are bonded in the monoanionic form, whereas in the monodithiolene complexes the dithioketone canonical form of the dithiolene ligand is more in evidence, as shown by the average C-S and C=C bond distances in the ligands. This is consistent with both complexes containing Ru(II) centers. The synthesis of the mixed-ligand bis(dithiolene) complex [Ru(SCH=CPhS)(S2C2Ph2)(PPh3)] has been achieved and it is shown that the bis(dithiolene) complexes undergo relatively slow scrambling of the dithiolene ligands in solution. The complex [Ru(SCH=CFcS)(2)(PPh3)] containing two ferrocenyl-substituted dithiolene ligands, was also prepared, but attempts to establish the degree of electrochemical communication between them were hampered by instability and the irreversible nature of the redox processes.