The synthesis and structure of heteroleptic tris(diimine)ruthenium(ii) complexes
Abstract
The reactions of bidentate diimine ligands (L2) with cationic bis(diimine) [Ru(L)(L1)(CO)Cl]+ complexes (L, L1, L2 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)(L1)(L2)]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′-Me2bpy)](PF6)3·½H2O, [Ru(bpy)(5,6-Me2phen)(Hdpa)](ClO4)2, [Ru(bpy)(phen)(5,6-Me2phen)](ClO4)2, [Ru(bpy)(5,6′-Me2phen)(4,4′-Me2bpy)](PF6)2·EtOH, [Ru(4,4′-Me2bpy)(phen)(Hdpa)](PF6)2·MeOH and [Ru(bpy)(4,4′-Me2bpy)(Hdpa)](ClO4)2·½Hdpa (where Hdpa is di(2-pyridyl)amine). A novel feature of the first complex is the presence of a dinuclear anionic adduct, [K2(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.