FACTORS INVOLVED IN THE ELECTRONIC MOBILITY WITHIN THE CHELATE RING OF THE LINKAGE ISOMERS OF CO(II), NI(II) AND CU(II) COMPLEXES WITH VICINAL OXIME IMINE LIGANDS - AN IR STUDY

The electron mobility in the five- and six-membered chelate rings of t he LM complexes [H-2L = N, N'-ethylenebis(isonitrosoacetylacetoneimine ); M = divalent Ni, Co or Cu ions] is discussed in relation to the sta bility of the chelate isomers. The vibrational energies of the N-O, C= N and C=O binding are related to the second or third ionization potent ial of the metal ions. This relationship is used for the calculation o f nu (N-O), nu (C=N) and nu (C=O) of a metal complex from the data of a prepared metal complex. The role of non-coordinated carbonyl group i s discussed in relation to the imine nephelauxetic power which account s for: (a) the conversion of the chelate isomer; and (b) the surprisin g stability of both modes of coordination by the oximato group in bis( 4-iminopentane-2,3-dione 3-oximato) nickel(II).