Volume 40, Issue 2

The present review aims to give a comprehensive survey about the chemistry of rhenium(V)-oxo complexes of general formula [ReOX 2 (N∩O)(EPh 3 )], where X=Cl, Br, I, E=P, As, and N∩O stands for uninegative chelating N∩O-ligand, carried out within the last four decades. In addition to the synthesis aspects, the available structural data as well as the results issued from techniques such as infrared and ultraviolet-visible spectroscopies are collected and discussed. Furthermore, a brief description of the applications of these compounds in catalysis is included.

This review includes 70 monomeric high-spin complexes of the following general compositions: [Fe(II)(η 3 -pdc)(L) 3 ], [Fe(III)(η 3 -pdc)(L) 3 ] + , [Fe(II)(η 3 -pdc) 2 ] 2− and [Fe(III)(η 3 -pdc) 2 ] − (pdc = pyridine-2,6-dicarboxylate (−2)). Each Fe(II) atom has a distorted octahedral geometry. The Fe(III) atoms have a distorted octahedral geometry (most common) and in some examples have a distorted pentagonal-bipyramidal geometry. The chelating donor ligands create varieties of n -membered metallocyclic rings: ONO, OCO, NC 2 N, OC 2 N, OC 2 NO and OC 3 O. Some cooperative effects between Fe(II) and Fe(III) complexes were found and discussed. There are complexes that are examples of distortion isomerism.