Volume 31, Issue 2-3

No abstract available

The synthesis, structure, bonding motif, reaction behavior, electrochemistry, spectro-electrochemistry and some potential applications of multi-sandwich and/or half-sandwich substituted 5-membered heterocycles including group 3–6 main group elements and/or d -block transition metals, as well as current trends in this field of chemistry, are reported.

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.