Abstract
Complexes of Co
II, Ni
II and Cu
II with substituted phenylazo-6-aminouracils containing (-H,
p-OH,
p-CH
3,
p-OCH
3
p-COOH) have been synthesized and characterized by elemental analysis, magnetic measurements and spectral measurements (IR, UV–Vis, ESR). Infrared spectra assigned the fundamental bands of the major groups, OH, NH, CH, CO, CN, NN, CN and CO (ν, δ and γ modes of vibrations). The absence of ν
OH and the appearance of ν
CO in the infrared spectra of the free ligands of 5-(
p-tolyl and
p-anisylazo)-6-aminouracil, assigned the keto structure, whereas in cases of 5-(phenyl,
p-hydroxyphenyl and
p-carboxyphenylazo)-6-aminouracil ligands, the data showed strong ν
OH and ν
CO bands to assign keto–enol tautomerisms. The modes of interactions between the ligands and the metals were discussed, where oxygen and nitrogen atoms (of amino–amide groups) are involved in chelation. The azo group was not involved in chelation for all the prepared complexes except those of copper complexes derived from 5-(phenyl,
p-tolyl,
p-hydroxyphenyl and
p-carboxyphenylazo)-6-aminouracils. The room temperature effective magnetic moment values, the Nujol mull spectra and ESR proved that all the prepared complexes were of octahedral geometry, except the nickel complex derived from 5-(phenylazo)-6-aminouracil and cobalt complex derived from 5-(
p-carboxy-phenylazo)-6-aminouracil were square planar.