Ru-σ-alkynyl compounds of tetraanilinopyridinato-diruthenium(II,III) core: synthesis and structural characterization

Synthesis and characterizations are reported for three diruthenium(II,III) compounds of general formula Ru2(ap)4(CCR), where ap=2-anilinopyridinate and R=Si(CH3)3 (3), H (4), and CH2OCH3 (5). Molecular structure determination reveals that the Ru–Ru bond lengths are 2.3162(5) and 2.3234(7) Å for 3 and 5, respectively, while the CC bond is not significantly elongated compared with the free alkyne. Compounds 3–5 undergo reversible one-electron oxidation and reduction at potentials around 200 and −1030 mV, respectively. At more positive potential, compounds 3 and 4 undergo the second one-electron oxidation quasireversibly or irreversibly without decomposition, while compound 5 is oxidatively degraded.