Binuclear manganese(III) complexes of an unsymmetric pyrazolate-based compartmental ligand with hard donor set

The synthesis, crystal structure and magnetic properties of manganese(III) binuclear complexes [Mn(2)(III)(L-3H)(2)(CH(3)OH)(4)]center dot 2CH(3)OH (1) and [Mn(2)(III)(L-3H)(2)(Py)(4)]center dot 2Py (2) (L = 3-[(1E)-N-hydroxyethanimidoyl]- 4-methyl-1H-pyrazole-5-carboxylic acid) are reported. The ligand contains two distinct donor compartments formed by the pyrazolate-N and the oxime or the carboxylic groups. The complexes were characterized by X-ray single crystal diffraction, revealing that both 1 and 2 consist of dinuclear units in which the two metal ions are linked by double pyrazolate bridges with a planar {Mn(2)N(4)} core. Cryomagnetic measurements show antiferromagnetic interaction with g = 1.99, J = -3.6 cm (1), Theta = -2.02 K for 1 and g = 2.00, J = -3.7 cm (1), Theta = 1.43 K for 2. (C) 2010 Elsevier B. V. All rights reserved.