Synthesis and characterization of new manganese(III) complexes having N4O2 donor sets: study of the X-ray crystal structure of [Mn(5-Br-sal-N-1,4,7,10)]ClO4 and its electron transfer kinetics with sulfur(IV)

A series of manganese(III) complexes with hexadentate Schiff base ligand having N4O2 donor sets have been synthesized. One of them, [Mn(5-Br-sal-N-1,4,7,10)]ClO4 (1), has been characterized through X-ray crystallography. In the complex cation of 1, the manganese is coordinated by the hexadentate 5-Br-sal-N-1,4,7,10 ligand producing a distorted octahedral MnN4O2 geometry with average MnO and MnN (imine), MnN (amine) bond lengths of 1.952(4), 1.988(5) and 2.244(5) Å, respectively. The presence of two long MnO and MnN bonds are consistent with Jahn–Teller effects. The electron transfer reactivity of 1 with sulfur(IV) has been studied over a range of pH 2.60–6.00.