Thermoanalytical and IR-spectral investigation of Fe(III) complexes with nicotinamide

The paper describes the synthesis, characterization and thermal decomposition of the complexes FeBr3(na)(3).3H(2)O(I), Fe2O(Clpr)(4)(na)(4).4H(2)O(II) and Fe3O(ac)(6)(NO3)(na)(5).Me2CO (III), (where na = nicotinamide, Clpr = CH3CHClCOO-, ac = CH3COO- and Me = methyl). Characterization and chemical composition of the complexes were carried out using elemental analysis, complexometric titration and IR spectra. Schemes of thermal destruction of these complexes are suggested. Heating of these compounds first resulted in a release of solvent molecules. The thermal stability of these complexes can be ordered in the sequence: III < I = II. The thermal decomposition of the complexes produced FeO (I) and Fe2O3 (II and III) as the final solid products. Nicotinamide was coordinated to Fe(III) through the nitrogen atom of its heterocyclic ring. IR data suggested the bridging coordination and ionic bond of carboxylates in complex II and bridging coordination of carboxylates in complex III to Fe(III). (C) 2002 Elsevier Science B.V. All rights reserved.