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 IIIORu III(C 2O 4)(Py) 3] and [(4-MePy) 3(C 2O 4)Ru IIIORu III(C 2O 4)(4-MePy) 3]·2-Mebmz ·3H 2O (Py = pyridine; 4-MePy = 4-methylpyridine; 2-Mebmz = 2-methylbenzimidazole)

Abstract

Two oxo-bridged dinuclear ruthenium(III) complexes, [(Py) 3(C 2O 4)Ru IIIORu III(C 2O 4)(Py) 3] ( 1) and [(4-MePy) 3(C 2O 4)Ru IIIORu III(C 2O 4)(4-MePy) 3]·2-Mebmz ·3H 2O ( 2) (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·S 2 (S 1=S 2=1/2) , yielding an antiferro-magnetic spin coupling constant J=−53 cm −1 .