Preparation and characterization of some Schiff base complexes of first row transition elements

Abstract

The bis-chelate complexes of the tranrsitlon metal ions cobalt(ll), nickel(ll), copper(lI) and zinc(II) with the Schiff bases derived from substituted salicyldldehydes. XC₆H₃(OH)CHO (where X = H, 3-0CH₃ and 5,6- benzo), and 2-aminopyridines, YC₅H₃ N(NH₂) where Y = 4-methyl, 5-methyl, 6-methyl, and 4,6-dimethyl have now been prepared elemental, electronic-, near-infrared-, infrared-, and nor spectra along with the magnetic data have been used to characterize the complexes and assess the influence of the pyridine ring on the coodination geomelry of the metal centre. Whereas Co(II), Ni(ll) and Zn(lI)- bis-chelates prefer tetrahedral coordination, Cu(II) assumes a planar geometry. Neither the pyridine ring in the Schiff-bases, XC₆H₃ (OH)CH=NC₅H₃N(Y), nor the substituent, Y, exihibits sufficient electronic or steric influence for the deviation from the ideal coordination geometries of Co(II), Ni(II), Cu(II) and Zn(Il) to occur.