Inorganic Chemistry, Vol.43, No.19, 6108-6113, 2004
Isovalent and mixed-valent diruthenium complexes [(acac)(2)Ru-II (mu-bpytz)Ru-II(acac)(2)] and [(acac)(2)Ru-II(mu-bpytz)Ru-III(acac)(2)](ClO4) (acac= acetylacetonate and bpytz=3,6-bis(3,5-dimethylpyrazolyi)-1,2,4,5-tetrazine): Synthesis, spectroelectrochemical, and EPR investigation
The title compounds involving the structurally characterized bridging ligand bpytz were characterized, showing very strong electrochemical stabilization of the mixed-valent (RuRuIII)-Ru-II state (K-c = 10(13.9)) but no detectable (epsilon < 20 M-1 cm(-1)) intervalence charge-transfer band in the infrared region. In situ reduction of the neutral precursor produces a diruthenium(II) complex of the bpytz radical anion according to EPR spectroscopy, whereas oxidation of the mixed-valent form leads to a diruthenium(III) species.