Presented herein is the synthesis and characterization of four diruthenium(II,III) compounds of formulas Ru2(Xap)4(CC-C6H4-4-NH2) (Xap is 2-anilinopyridinate, 1a; and 2-(3,5-dimethoxy)anilinopyridinate, 1b) and Ru2(Xap)4(CC-C6H4-3-NH2) (2a/2b). X-ray structural studies of compounds 1b and 2a revealed minimal changes in the coordination sphere of the Ru2 core. Voltammetric measurements showed that compounds 1 exhibit three one-electron redox processes: a reversible reduction of Ru2, a reversible oxidation of Ru2, and a quasi-reversible oxidation of an amino group. Compounds 2 display the same Ru2-based redox processes but not the −NH2 oxidation. Compounds 1a/1b were successfully converted to the corresponding diazonium salts [Ru2(Xap)4-(CC-C6H4-4-N2)](BF4) (3a/3b) via oxidation by nitrosonium tetrafluoroborate, which was generated in situ from t-BuONO and BF3. However, the attempt to convert compounds 2 to the corresponding diazonium salts was unsuccessful. DFT calculations of model compounds were performed to rationalize some unusual structural and electrochemical characteristics observed for compounds 1/2.

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