Half-sandwich ruthenium, rhodium and iridium complexes containing dipyridyl amine based ligands

Compounds derived from the reactions of dimeric arene ruthenium [{(η6-arene)Ru(μ-Cl)Cl}2] (arene = benzene and p-cymene) and structurally analogous rhodium and iridium complexes [{(η5-C5Me5)M(μ-Cl)Cl}2] (M = Rh or Ir) with 2-chloro-4,6-(di-2-pyridylamino)-1,3,5-triazine (cddt) and 2,4,6-tris(di-2-pyridylamino)-1,3,5-triazine (tdat) are reported. Compounds under investigation have been characterized by elemental analyses, NMR (1H and 13C), electronic absorption, emission spectral and electrochemical studies. Structures of the dinuclear compounds [{(η6-C10H14)RuCl}2(cddt)](PF6)2, [{(η5-C5Me5)RhCl}2(cddt)]Cl2·6H2O and trinuclear compound [{(η6-C6H6)RuCl}3(tdat)]Cl3·4H2O have been determined crystallographically. Among cddt containing compounds the {(η6-C10H14)RuCl}- units in [{(η6-C10H14)RuCl}2(cddt)](PF6)2 are anti, while {(η5-C5Me5)RhCl}- in the rhodium compound [{(η5-C5Me5)RhCl}2(cddt)]Cl2·6H2O are syn with respect to triazine ring. Cyclic voltammetric studies on the compounds suggested lack of communication between the metal centres. Furthermore, although tdat is luminescent at room temperature compounds under investigation containing this ligand are non-luminescent in acetonitrile.