Metal–metal interactions in dinuclear ruthenium complexes incorporating “stepped-parallel” bridging ligands: synthesis, stereochemistry and intervalence charge transfer

Abstract

The synthesis and separation of the diastereoisomeric forms of the complexes [{Ru(bpy)₂}₂(μ-BL)]⁴⁺ based on the series of “stepped-parallel” bridging ligands 2,5-bis(2-pyridyl)pyrazine (2,5-dpp), dipyrido(2,3-a;2′,3′-h)phenazine (dpop) and azobis(2-pyridine) (apy) are reported. Electrochemical and intervalence charge transfer (IVCT) studies on the complexes reveal a high degree of metal–metal interaction, consistent with a negligible solvent dependence of the IVCT parameters in each case. The results support a Class II–III classification for the systems.