The synthesis and structure of heteroleptic tris(diimine)ruthenium(II) complexes

The reactions of bidentate diimine ligands (L-2) with cationic bis(diimine)[Ru(L)(L-1)(CO)Cl](+) complexes (L, L-1, L-2 are dissimilar diimine ligands), in the presence of trimethylamine-N-oxide (Me3NO) as a decarbonylation reagent, lead to the formation of heteroleptic tris(diimine) ruthenium(II) complexes, [Ru(L)(L-1)(L-2)](2+). Typically isolated as hexafluorophosphate or perchlorate salts, these complexes were characterised by UV-visible, infrared and mass spectroscopy, cyclic voltammetry, microanalyses and NMR spectroscopy. Single crystal X-ray studies have elucidated the structures of K[Ru(bpy)(phen)(4,4'-Me(2)bpy)](PF6)(3).1/2H(2)O, [Ru(bpy)(5,6-Me(2)phen)(Hdpa)](ClO4)(2), [Ru(bpy)(phen)(5,6-Me(2)phen)](ClO4)(2), [Ru(bpy)(5,6'-Me(2)phen)(4,4'-Me(2)bpy)](PF6)(2).EtOH, [Ru(4,4'-Me(2)bpy)(phen)(Hdpa)](PF6)(2).MeOH and [Ru(bpy)(4,4'-Me(2)bpy)(Hdpa)](ClO4)(2).1/2Hdpa (where Hdpa is di(2-pyridyl) amine). A novel feature of the first complex is the presence of a dinuclear anionic adduct, [K-2(PF6)(6)](4-), in which the two potassium centres are bridged by two fluorides from different hexafluorophosphate ions forming a K2F2 bridging unit and by two KFPFK bridging moieties.