An intramolecular antiferromagnetically coupled pentanuclear homoleptic Mn(II) cluster: Synthesis, crystal structure, spectral and magnetic property

Abstract: A pyrazole based ditopic ligand 5(E)-5-methyl-N′-(pyridin-2-ylmethylene)-1H-pyrazole-3-carbohydrazide (PzOPyH), prepared by the reaction between 5-methylpyrazole-3-carbohydrazide and pyridine-2-carbaldehyde, reacts with Mn(ClO4)2·6H2O to form a self-assembled, antiferromagnetically coupled alkoxide bridged pentanuclear Mn(II) homoleptic cluster complex [Mn5(PzOPy)6](ClO4)4 (1). The complex has a central Mn5(μ-O6) core involving six ligand molecules. This pentanuclear core has a trigonal bipyramidal arrangement of Mn(II) atoms, where, the axial metal centers (Mn2 and Mn_2) have a N3O3 chromophore and the equatorial centers (Mn1, Mn_1 and Mn3) have N4O2 chromophore with distorted octahedral arrangement around the metal centers. Intramolecular antiferromagnetic interaction between Mn(II) centers (J =−1.42, S =5/2) is the signature of the molecule. [Copyright &y& Elsevier]