SYNTHESIS, MOSSBAUER AND OTHER SPECTRAL STUDIES ON SOME PENTACOORDINATED COMPLEXES OF THIAZOLES WITH IRON(III) IMIDES

Complexes of the type [Fe(TZ)(2)(Im)(2)(OH)].H2O and [Fe(ATZ)(Im)(2)(O H)].H2O, where Im = deprotonated phthalimide or succinimide, TZ = thia zole or benzothiazole and ATZ = 2-aminothiazole or 2-aminobenzothiazol e, were prepared and characterized. Thermal analysis confirmed the pre sence of one molecule of water as lattice water in each case. Elementa l analyses, conductivity measurements and molecular mass determination s indicated the complexes as non-electrolytic and five-coordinate comp ounds. IR spectra confirmed the coordination of the deprotonated imide ion through nitrogen; thiazole, benzothiazole were coordinated throug h sulphur whereas 2-aminothiazole and 2-aminobenzothiazole formed chel ates by coordinating through the sulphur atom of the heterocyclic ring and the nitrogen of the primary amino group. H-1 NMR studies supporte d the above types of coordination. Magnetic moments and electronic spe ctral studies proved the presence of five-coordinate iron(III) ion und er the influence of the square pyramidal ligand field. Mossbauer spect ra also indicated the square pyramidal structure of the complexes. The characteristic values of Mossbauer isomer shifts and quadrupole split tings were found in the range of 0.36-0.42 mm/sec and 0.485-0.520 mm/s ec for the TZ series and 0.34-0.40 mm/sec and 0.400-0.524 mm/sec for t he ATZ series of complexes.