Dinitrogen-bridged diruthenium complexes bearing 2,6-pyridinedicarboxylate in the mixed-valence state

A dinitrogen-bridged diruthenium complex bearing 2,6-pyridine-dicarboxylate (pydc^2-), which coordinates in a κ²-<i>ON</i> bidentate mode, with ammine and hydroxido ligands has been synthesized by reactions of ruthenium(III) and/or ruthenium(II) complexes with hydrazine or dinitrogen as a dinitrogen source. A reaction of the diruthenium complex with pyridine affords a pyridine-substituted diruthenium complex. The electronic structures of the diruthenium complexes in a mixed-valence state have been investigated using UV-vis-NIR and IR spectroscopy and electrochemical methods.