X-Ray Structure, Ligand Substitution, and Other Properties of Trinuclear Ruthenium Complex, [Ru3(μ3-O)(μ-C6H5COO)6(py)3](PF6) (py = pyridine), and X-Ray Structure of Dinuclear Ruthenium Complex, [Ru2(μ-C6H5COO)4Cl]

Crystal structure of an oxo-benzoate-bridged trinuclear ruthenium complex, [Ru3(μ3-O)(μ-C6H5COO)6(py)3](PF6) (py = pyridine) (1), was determined for the first time for the complexes with a Ru3(III,III,III)(μ3-O) core. The complex crystallizes in hexagonal space group P63 with a = 13.619(6), c = 19.204(9) Å, V = 3085(3) Å3, and Z = 2. The Ru···Ru distance of 3.350(2) Å is similar to those of the trinuclear complexes of other metal ions, [MIII3(μ3-O)(μ-RCOO)6(L)3]+ (L = neutral unidentate ligand). The complex in 0.1 M (n-C4H9)4NPF6-acetonitrile at 20 °C shows four reversible one-electron processes at E1⁄2 = +1.58, +0.71, −0.26, and −1.54 V vs. Ag/Ag+ (0.1 M AgClO4). It undergoes pyridine-d5 exchange with the first-order rate constant, 4.9 × 10−6 s−1 at 60 °C ([1] = 4.7 mM, [py-d5] = 387 mM). Small modification of the synthetic procedure of the trinuclear complex leads to the precipitation of the crystals of well-known type of dimeric ruthenium (II,III) complex, [Ru2(μ-C6H5COO)4Cl], which crystallizes in monoclinic space group C2/c with a = 21.668(10), b = 10.741(8), c = 12.797(5) Å, β = 110.22(4)°, V = 2795(3) Å3, and Z = 4. The crystal contains infinite zig-zag chain of ···Cl–Ru–Ru–Cl···along c-axis with Ru–Ru–Cl of 175.5(1)°, Ru–Cl–Ru of 118.1(1)°, and the Ru–Ru distance of 2.290(1) Å.