Multiple MMCT properties of the diruthenium-based cyanido-bridged complex RuVI2-NC-Ru II -CN-RuVI2.

The diruthenium-based linear mixed valence complex trans -[Ru 2 (ap) 4 -NC-Ru(DMAP) 4 -CN-Ru 2 (ap) 4 ][PF 6 ] 2 (12+[PF6]2) (ap = 2-anilinopyridinate, DMAP = 4-dimethylaminopyridine) and its two-electron oxidation product 14+[PF6]4 have been synthesized and fully characterized. The investigation reveals that complex 12+ displays a single MMCT transition, whereas complex 14+ has three identified MMCT transitions (MMCT-1, MMCT-2 and MMCT-3) upon oxidation. Interestingly, MMCT-2 in complex 14+ might result from the transition from the Ru III -NC-Ru II -CN-Ru III component, which is composed of the central Ru II and its two neighboring Ru III atoms from the cluster RuVI2 units, to both the terminal Ru III atoms of the same cluster RuVI2 units, which is supported by the TDDFT calculations.