Isomers in the chemistry of manganese coordination compounds

Abstract

The coordination chemistry of manganese covers wide fields, as shown by a survey covering the crystallographic and structural parameters of over 700 examples. About 10% of those complexes exist as distortion isomers and are summarized. These are discussed in terms of the coordination about the Mn(I) to Mn(IV) mixed valence Mn(II)/Mn(III); Mn(III)/Mn(IV) and correlations are drawn between donor atoms, bond length and interbond angles. Distortion isomers differ only by degree of distortion in Mn–L bond distances and L–Mn–L bond angles. Interestingly, in the chemistry of manganese coordination complexes, only distortion isomers are present. The isomers crystallized in the following systems: monoclinic (×40)>triclinic (×22)>orthorhombic (×8)>tetragonal (×4), trigonal and cubic each (×1). The nuclearity ranges from monomeric to polymeric, and a wide range of ligand systems are found, with O and N donor atoms by far prevailing. The manganese are three-, four-, five-, six- and seven-coordinated, from which six-coordinated by far prevails.