Effects of Added Metal Ions on the Behaviour of the Azo Chromophore in Heterocyclic Copolymers
Ana Emandi, Mirela Calinescu and Aurelia Meghea
A new series of mononuclear complexes of the general formulas Na[ML1 (alyl)2 ] where M=Ni(II), Cu(II), Co(II); Na[ML2 (alyl) ] where M=VO2+; [ML1 (alyl)2 ] where M=Fe(III), Zn(II) with the mixed ligands L1 = 1-(2’-benzthyazolyl)-3- methyl-4-azo-(4’-nitrophenyl)-5- pyrazolona , L2 = 1-phenyl- 3-methyl-4-azo-(2’- carboxyphenylen) -5- pyrazolona, alyl=alyacetoacetate and their metal complex copolymers with vinyl acetate have been prepared and characterized on the basis of the elementar analysis, conductance data and vibrational spectra. The behaviour of the azo N=N chromophore in the free ligands, in the metal complexes monomers and in the metal complexes copolymers was investigated by the UVVIS spectra by the diffuse reflectance technique and was explained on the basis of the molecular orbital theory (MOT). All shifts of the absorption bands of azo –N==N- group are discussed in terms of the π- delocalization effects that increases in the metal complex copolymer bone and the p&Mac185; – d&Mac185; interaction in the metal complex monomers and copolymers comparable with the free ligands.