Ru-sigma-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 Ru-2(ap)(4)(C=CR), where ap = 2-anilinopyridin ate and R = Si(CH3)(3) (3), H (4), and CH2OCH3 (5). Molecular structure det ermination reveals that the Ru-Ru bond lengths are 2.3162(5) and 2.3234(7) Angstrom 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 se cond one-electron oxidation quasireversibly or irreversibly without decompo sition, while compound 5 is oxidatively degraded. (C) 2000 Elsevier Science S.A. All rights reserved.