Copper(ii) Coordination Compounds: Classification and Analysis of Crystallographic and Structural Data Ii. Mononuclear-, Hexa-, Hepta-and Octacoordinate Compounds

This review summarizes the data for over five hundred and fifty six-, seven- and eight-coordinate Cu(II) coordination compounds. The six-coordinate derivatives are mostly distorted tetragonal (elongation along a single C 4 axis). The seven-coordinate derivatives are only penta-gonal-bipyramidal with different degrees of distortion and the eight-coordinate complexes are dodecahedral. The most common ligands are O- and N-donors. There is a trend for the Cu-L distance to increase with covalent radius of the coordinated atom and also increasing coordination number. In general, Cu(II) compounds "prefer" a monoclinic class and are blue or green. Several relationships were found and discussed. The data are compared and discussed with those of four- and five-coordinate Cu(II) compounds.