Synthesis and magnetic properties of binuclear manganese(II) complexes with an iodanilate bridge

Four iodanilato-bridged manganese(II) binuclear complexes of the formula [Mn-2(IA)L-4](ClO4)(2), where L denotes 4,4'-dimethyl-2,2'-bipyridine (Me-2-bpy), 5-methyl-1,10-phenanthroline (Me-phen), 5-chloro-1,10-phenanthroline (Cl-phen) or 5-nitro-1,10-phenanthroline (NO2-phen), and IA represents the dianion of iodanilic acid, have been synthesized and characterized by elemental analyses, molar conductivity and room temperature magnetic moment measurements, and by spectroscopy. It is proposed that these complexes have IA-bridged structures and consist of two manganese(II) ions in a distorted octahedral environment. The complexes [Mn-2(1A)(Me-2-bpy)(4)](ClO4)(2) (1) and [Mn-2(1A)(Me-phen)(4)](ClO4)(2) (2) were characterized by variable temperature magnetic susceptibility measurements (4-300 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 integral J = - 3.29 cm(-1) for (1) and J = 4.58 cm(-1) for (2). This result indicates that there is a weak antiferromagnetic spin-exchange interaction between the two Mn(II) ions within each molecule.