SYNTHESIS AND MAGNETIC STUDIES OF PHTHALATO-BRIDGED OXOVANADIUM(IV) BINUCLEAR COMPLEXES

Six new mu-phthalato binuclear oxovanadium(IV) complexes, namely [(VO) (2)(PHTH)(L)(2)]SO4 (L denotes 2,2'-bipyridine (bpy); 1,10-phenanthrol ine (phen); 4,4'-dimethyl-2,2'-bipyridine (Me(2)bpy); 5-nitro-1,10-phe nanthroline (NO2-phen); 5-chloro-1,10-phenanthroline (Cl-phen) and 5-m ethyl-1,10-phenanthroline (CH3-phen), where PHTH is the phthalate dian ion), have been synthesized and characterized by elemental analyses, I R, electronic spectra, magnetic moments at room temperature and molar conductivity measurements. The temperature dependence of the magnetic susceptibility of complexes [(VO)(2)(PHTH)(phen)(2)]SO4 (1) and [(VO)( 2)(PHTH)(CH3-phen)(2)]SO4 (2) was measured in 4-300 K range and the ob served data were successfully simulated by the equation based on the s pin Hamiltonian operator, (H) over cap=-2J (S) over cap(1) .($) over c ap(2), giving the exchange integrals J=-12.8 cm(-1) for 1 and J=-7.9 c m(-1) for 2. This indicates an antiferromagnetic spin-exchange interac tion between the metal ions within each molecule.