Correlation between the metal-nitrogen stretching frequency and the coordination number in zinc ammines

Abstract

The frequency of the principal Zn—N stretching mode at ca. 450 cm^–1, as determined by the laser Raman method, is reported for complexes of zinc containing the ligands ethylenediamine, diethylenetriamine, triethylenetetramine, 2,2′,2″-triaminotriethylamine, tris(2-dimethylaminoethyl amine and N,N′-dimethylethylenediamine. Evidence is presented for the existence of an empirical correlation between this frequency and the coordination number of the metal. This correlation appears to be independent of the phase, the nature of the nature other groups in the inner coordination sphere of the metal and the other groups bound to the coordinating nitrogen.