Synthesis, mass spectrometry, and spectroscopic properties of a dinuclear ruthenium complex comprising a 20 angstrom long fully aromatic bridging ligand

The luminescent dinuclear ruthenium complex [(bpy)(2)Ru(bqpy)Ru(bpy)(2)](4) (1) comprising the 20 Angstrom long fully aromatic bridging ligand bqpy h as been synthesized by successive reactions from suitable precursor complex es. Investigations in electrospray mass spectrometry and H-1 NMR spectrosco py have indicated the formation of supramolecular aggregates by strong pi-s tacking of the large aromatic parts. Despite the extended aromatic characte r of the bqpy bridging ligand, electrochemical and spectroscopic studies of the dinuclear complex have shown that the complex is composed of four noni nteracting parts: two Ru(bpy)(3)(2+)-type units bridged by two bqpy-localiz ed fragments similar to two fused phenazine moieties.