Polynuclear complexes of a dissociative excited state formed in the [Ru(bpy)2(CN)2]–HgCl2 system

Abstract

The complex cis-dicyanobis(2,2′-bipyridine)ruthenium(II) forms various bimetallic complexes with mercury(II)chloride, such as [(NC)Ru(bpy)₂(CN)–HgCl₂], [Cl₂Hg–(NC)Ru(bpy)₂(CN)–HgCl₂–(NC)Ru(bpy)₂(CN)–HgCl₂] and [Cl₂Hg–(NC)Ru(bpy)₂(CN)–(HgCl₂)] in CH₃CN. These polynuclear complexes of the equilibrium system have been identified and characterized by their formation constants and absorption spectra. Excitation of bimetallic complexes produces the MLCT state localized on [Ru(bpy)₂(CN)₂] ligand, resulting in the cleavage of the bond formed between the nitrogen atom of the coordinated cyanide ligand and the Hg(II) central atom in ground state. Unlike many photoinduced metal ligand dissociations, the dissociated fragment remains in a luminescent excited state.