Syntheses and Characterizations of Cyanido-bridged Dinuclear Ru-complexes and Their MMCT Properties in the One-electron Oxidation State

We have designed and synthesized a family of dinuclear cyanido-bridged complexes [PY5Me(2)Ru(mu-CN)Ru(dppe)CpMen][PF6](2) (PY5Me(2) = 2,6-bis (1,1-bis(2-pyridyl)ethyl) pyridine, Cp = cyclopentadienyl, n = 0, 2[PF6](2); n = 1, 3[PF6](2); n = 5, 4[PF6](2)) by using a mononuclear complex [PY5Me(2)Ru(mu-CN)][PF6] (1) as the pre-cursor. All the three complexes have been fully characterized by including single-crystal X-ray diffraction analysis. The one-electron oxidation complexes 2(3+), 3(3+) and 4(3+) obtained in situ all show a MMCT absorption band in the visible range. The MMCT energy increases as the redox potential of the N-terminal fragments decreases, and the redox potential decreases as the number of methyl groups on the cyclopentadiene of the cyanido-nitrogen coordi-nated Ru metal increases, supported by the TDF/TDDFT calculations.