One-pot synthesis of cis-bis(2,2′-bipyridine)carbonylruthenium(II) complexes from a carbonato precursor: X-ray crystal structures and electron transfer processes of the series complexes

Abstract

The reaction of Brønsted acids with cis-[Ru(bpy)2(CO3)] (bpy = 2,2′-bipyridine) under CO results in cleavage of the carbonato ligand and formation of cationic cis-[Ru(bpy)2(CO)L] n + complexes [L = ONO2 (1 +), OH2 (2 2+), Cl (3 +), OCOH (4 +), and OCOCH3 (5 +)]. The structures of 1 + and 2 2+ were confirmed by single-crystal X-ray diffraction. Crystal data for 1(PF6): monoclinic, P21/c, a = 10.5242(3), b = 15.4727(3), c = 14.6571(3) Å, β = 92.3219(9)°, V = 2384.77(9) Å3, Z = 4, D calcd = 1.806 g cm−3, 5460 unique reflections (R int = 0.032), R 1 = 0.0540 [I > 2σ(I)], wR 2 = 0.1642 (all reflections); crystal data for 2(ClO4)2 · H2O: monoclinic, C2/c, a = 20.4247(7), b = 10.0777(3), c = 15.6039(5) Å, β = 127.7569(8)°, V = 2539.31(14) Å3, Z = 4, D calcd = 1.769 g cm−3, 2895 unique reflections (R int = 0.036), R 1 = 0.0343 [I > 2σ(I)], wR 2 = 0.0907 (all reflections). Except for 2(PF6)2 the complexes exhibit oxidation at 1.02–1.30 V versus Fc+/Fc in acetonitrile. Bipyridine-centered reductions are also observed; these redox potentials depend on the nature of L. This convenient synthesis will be useful for producing cis-[Ru(bpy)2(CO)L] n +-type complexes in high yield.