Observation of supramolecular π–π dimerization of a dinuclear ruthenium complex by 1H NMR and ESMS

The dinuclear ruthenium complex of bis{dipyrido[3,2-f:2′,3′-h]quinoxalo}[2,3-e:2′,3′-l]pyrene (bqpy) forms dimers in solution maintained only by π–π stacking of the bridging ligand, stable enough to be observed not only by 1H NMR spectroscopy but also by electrospray mass spectrometry at low accelerating cone voltage.