A series of oxo-centred triruthenium-acetate complexes with valence III,III,II were prepared by reactions of [Ru₃^III,III,III]⁺ precursor [Ru₃O(OAc)₆(py)₂(CH₃OH)]⁺ (1) with 3-chloro-6-(pyrazol-1-yl)pyridazine (cppd), 3-chloro-6-(3,5-dimethylpyrazol-1-yl)pyridazine (cmppd), 3,6-bis(pyrazol-1-yl)pyridazine (ppd), 3,6-bis(3,5-dimethylpyrazol-1-yl)pyridazine (mppd) or 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (bptz). When neutral Ru₃^III,III,II precursor Ru₃O(OAc)₆(CO)(CH₃OH)₂ (2) was utilized, a stable low-valence Ru₃^III,II,II derivative complex was successfully isolated. As established through crystal structural analyses, they were derived from 1 or 2 by substitution of the axial methanol and one of six bridging acetates in the parent Ru₃(μ₃-O)(μ-OAc)₆ cluster core as well as one axial pyridine in some cases. As revealed by electrochemical and spectroscopic studies, substituting one of the six bridging acetates in the parent Ru₃(μ₃-O)(μ-OAc)₆ cluster core significantly modifies the electronic and redox characteristics. Compared with those for the parent compound [Ru₃O(OAc)₆(py)₃]⁺, triruthenium-based redox potentials of these derivatives show remarkable positive shifts.