Programmed assembly of heteromultinuclear complexes using 4′-diphenylphosphino-2,2′:6′,2″-terpyridine

The complex [Ru(tpy)(1)]2+ (tpy=2,2′:6′,2″-terpyridine; 1=4′-diphenylphosphino-2,2′:6′,2″-terpyridine) was prepared and reacted with trans-[PdCl2(NCMe)2] to give trans-[PdCl2{(μ-1)Ru(tpy)}2]4+ in high yield. With trans-[PtCl2(NCPh)2], [Ru(tpy)(1)]2+ reacts to yield trans-[PtCl2{(μ-1)Ru(tpy)}2]4+ which isomerizes in acetone solution; equilibrium is reached after ≈10 days at room temperature with a 1:19 trans:cis-isomer ratio. The reaction of trans-[PtCl2(NCPh)2] with ligand 1 gives cis-[PtCl2(1)2]. The single crystal structures of cis-[PtCl2(1)2]·H2O and cis-[PtCl2(1)2]·CH2Cl2·1.6C5H12 are described and significant differences in structure are observed dependent upon whether the solvate molecules are able to enter into hydrogen bonding interactions with the complex.