Studies on the synthesis and magnetic property of binuclear oxovanadium(IV) complexes bridged by chloranilato group

Abstract

Six novel oxovanadium(1V) binuclear complexes have been synthesized and characterized, namely, [(VO)z(CA)L2]SO4 [L denotes Emethyl-l,l0-phenanthroline (Me-phen); 2,9-dimethyl-1,lGphenanthroline (Mez-phen) ; 5-chloro-1,lO-phenant hroline (Cl-phen) ; diaminathane (en) ; 1,s diaminopropane (pn) and 1,2diaminopropane (ap) respectively.], where CA repraenta the dianion of chloranilic acid. Based on elemental anslysea, molar conductivity and mom temperature magnetic moment measurements, IR and electronic spectral studiea, it is proposed that there complexes have CA-bridged structures and consist of two vanadium(IV) ions in a quan-pyramidal environment. The complexes [(VO)z (CA)(Maphen)z]SO~ (1) and [(VO)p (CA)(Merphen)z]SO4(2) wen characterized by variable temperature magnetic susceptibility measurements (4-300 K) and the observed data were fitted to the modified Bleaney-Bowera equation by the least-squarea method, giving the exchange integral 3=-15.8 cm-' for 1 and J=-10.6 cm-l for 2. This result indicates that there is a weak antiferromagnetic spin-exchange interaction between the two VOz+ ions within each molecule.