Syntheses, crystal structures, susceptibility and EPR studies of oxo-bridged dinuclear ruthenium (III) complexes with linear Ru-O-Ru bonds: and [(Py)_3(C_2O_4)Ru~(III)ORu~(III)(C_2O_4)(Py)_3] and [(4-MePy)_3(C_2O_4)Ru~(III)ORu~(III)(C_2O_4)(4-MePy)_3

摘要

Two oxo-bridged dinuclear ruthenium(III) complexes, [(Py)_3(C_2O_4)Ru~(III)ORu~(III)(C_2O_4)(Py)_3] (1) and [(4-MePy)_3(C_2O_4)Ru~(III)ORu~(III)(C_2O_4)(4-MePy)_3](centre dot)2-Mebmz(centre dot)3H_2O (Py = pyridine; 4-MePy = 4-methylpyridine; 2-Mebmz = 2-methylbenzimidazole) were prepared by reacting RuCl_3 with K_2C_2O_4 and pyridine or 4-Methylpyridine and characterized by spectral data and X-ray crystallography. In both (1) and (2), the Ru-O-Ru bonds are linear, with the two C_2O_4~(2-) ions trans to each other at the terminal positions. The magnetic susceptibility of (1) was analyzed using a general isotropic exchange Hamiltonian H = -2JS_1(centre dot)S_2 (S_1 = S_2 = 1/2), yielding an antiferro-magnetic spin coupling constant J = -53 cm~(-1).