Synthesis, spectral and magnetic properties of mu-chloranilato manganese(II) binuclear complexes

Five new manganese(II) binuclear complexes have been synthesized, namely [Mn-2(CA)L-4](ClO4)(2) [L denotes 2,2'-bipyridine (bpy); 1,10-phenanthroline (phen); diaminoethane ten); 1,3-diaminopropane (pn) and 1,2-diaminopropane (ap)], where CA represents the dianion of chloranilic acid. Based on elemental analyses, molar conductivity and room temperature magnetic moment measurements, spectroscopic studies, it is proposed that these complexes have CA-bridged structures and consist of two manganese(II) ions in a distorted octahedral environment. The complexes [Mn-2(CA)(bpy)(4)](ClO4)(2) (1) and [Mn-2(CA)(phen)(4)](ClO4)(2) (2) were characterized by variable temperature magnetic susceptibility measurements (4 similar to 300 K)and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, (H) over cap = -2J (S) over cap(1) .(S) over cap(2), giving the exchange parameter J = -2.8 cm(-1) for (1) and J = -7.9 cm(-1) for (2). This result indicates that there is a weak antiferromagnetic spin-exchange interaction between two the Mn(II) ions within each molecule.