FERROMAGENETIC OXALATE-BRIDGED TRINUCLEAR CU(II)-CR(III)-CU(II) COMPLEXES

Two new oxalate-bridged triheteronuclear complexes, [Cu2(phen)2Cr(OX)3 ]NO3 and [Cu2(Mebpy)2Cr(OX)3]NO3 have been characterized, where phen a nd Mebpy denote 1, 10-phenanthroline and 4,4-dimethyl-2, 2-bipyridyl r espectively. The temperature dependence of magnetic susceptibilities o f complexes has been studied in 4.2 approximately 300K range, and the exchang integral J(Cu-Cr) is found to be 35.18cm-1 for [Cu2(Mebpy)2Cr( OX)3]NO3 and 30.24cm-1 for [Cu2(phen)2Cr(OX)3]NO3 on the base of spin Hamiltonian H = - 2J (S(Cu1).S(Cr)+S(Cu2)S(Cr)). The results are comme nsurate with ferromagnetic interactions between the Cu(II) and Cr(III) ions.