Synthesis, Characterization and Antiferromagnetic Interaction in Oxalato-Bridged Chromium(III)-Chromium(III) Binuclear Complexes

Two new μ-oxalato-bridged binuclear chromium(III) complexes, [Cr 2 (ox)(salen)(bpy) 2 ]-(NO 3 ) 2 (1) and [Cr2(ox)(salen)(phen)2](N03)2 (2) [where salen = N,N'-ethylenebis-(salicylideneiminate), ox = oxalato, bpy = 2,2'-bipyridine and phen = 1,10-phenanthroline], have been synthesized by the strategy of 'complex as ligand', and characterized by elemental analyses, molar conductance and magnetic moments of room-temperature measurements, and spectroscopic studies. It is proposed that the two complexes have extended ox-bridged structures consisting of two chromium(III) ions, each in an octahedral environment. The two complexes were further characterized by variable temperature magnetic susceptibility (4.2-300 K) measurements and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, H = -2JS 1 .S 2 , giving the exchange integrals J = -2.78 cm -1 for (1) and J =-3.85 cm -1 for (2). This result indicates the presence of weak antiferromagnetic interaction between the metal ions within each molecule.