Synthesis, Mössbauer and Other Spectral Studies on Some Penta-Coordinated Complexes of Thiazoles With Iron(III) Imides

Abstract

Abstract Complexes of the type [Fe(TZ)2(Im)2(OH)].H2O and [Fe(ATZ)(Im)2(OH)].H2O, where Im = deprotonated phthalimide or succinimide, TZ = thiazole or benzothiazole and ATZ = 2-aminothiazole or 2-aminobenzothiazole, were prepared and characterized. Thermal analysis confirmed the presence of one molecule of water as lattice water in each case. Elemental analyses, conductivity measurements and molecular mass determinations indicated the complexes as non-electrolytic and five-coordinate compounds. IR spectra confirmed the coordination of the deprotonated imide ion through nitrogen; thiazole, benzothiazole were coordinated through sulphur whereas 2-aminothiazole and 2-aminobenzothiazole formed chelates by coordinating through the sulphur atom of the heterocyclic ring and the nitrogen of the primary amino group. 1H NMR studies supported the above types of coordination. Magnetic moments and electronic spectral studies proved the presence of five-coordinate iron(III) ion under the influence of the square pyramidal ligand field. Mössbauer spectra also indicated the square pyramidal structure of the complexes. The characteristic values of Mössbauer isomer shifts and quadrupole splittings were found in the range of 0.36–0.42 mm/sec and 0.485-0.520 mm/sec for the TZ series and 0.34–0.40 mm/sec and 0.400–0.524 mm/sec for the ATZ series of complexes.