Synthesis and magnetic studies of copper( II)-manganese(II) heterobinuclear complexes with an oxamido bridge

Four new copper(II)-manganese(II) heterobinuclear complexes bridged by N, N ' -bis[2-( dimethylamino) ethyl)]oxamido dianion (dmoxae) and end-capped wi th 1,10-phenanthroline (phen), 5-methyl-1, 10-phenanthroline (Mephen), diam inoethane ten) or 1,3-di-aminopropane (pn), respectively, namely, [Cu (dmox ae)MnL2] (ClO4)(2) (L = phen, Mephen, en, pn), have been synthesized and ch aracterized by elemental analyses, IR, electronic spectral studies, and mol ar conductivity measurements, The electronic reflectance spectrum indicates the presence of spin exchange-coupling interaction between bridged copper( II) and manganese(II) ions. The cryomagnetic measurements (4.2-300 K) of [C u(dmoxae)Mn(phen)(2)] (ClO4)(2) (1) and [Cu (dmoxae)Mn(Mephen)(2)] (ClO4)(2 ) (2) complexes demonstrated an antiferromagnetic interaction between the a djacent manganese(II) and copper(II) ions through the oxamido-bridge within each molecule. On the basis of spin Hamiltonian, (H) over cap = - 2J (S) o ver cap (1) . (S) over cap (2), the magnetic analysis was carried out for t he two complexes and the spin-coupling constant (J) was evaluated as - 35,9 cm(-1) for 1 and - 32.6 cm(-1) for 2. The influence of methyl substitution s in the amine groups of the bridging ligand on magnetic interactions betwe en the metal ions of this kind of complexes is also discussed.