Synthesis, spectral, thermal and electrochemical studies of iron(III) complexes with 2,3-dimethyl-1-phenyl-4-( 4-methoxy-2-phenol azo )-5-pyrazolone and 2,3-dimethyl-1-phenyl-4-(3-methoxy-2-phenol azo)-5-pyrazolone

Department of Chemistry, University College, Thiruvananthapuram-695 034, Kerala, India E-mail: drmlhnair@gmail.com Manuscript received 26 October 2009, accepted 15 July 2010 Some novel iron(III) complexes of formulae [Fel1(X)3], [FeL1(Y)(X)2], [FeL1)2(Z)X]Z, [Fe(L2)2(X)2]X, [FeL2(X)3(H2O)], [FeL2(Y)2(H2O)X, [FeL2(Z3)(H2O)], [Fe2(L2)2(X)6] (where L1 = GAAP, guaiacolazoantipyrine; L2 = MPAAP, 3-methoxy phenol azo antipyrine; X = Cl/Br/NO3; Y = NCS; Z = CIO4) have been synthesized and charac­terized by elemental analysis, molar conductance, magnetic susceptibility data and spectral (IR, UV-Visible, 1H NMR and FAB-mass) studies. The thermal behaviour of one of the complexes was investigated by thermogravimetric tech­niques. The X-ray diffraction studies of the complex [Fe(MPAAP)(NCS)2(H2O)Cl] indicated orthorhombic crystal lattice with unit cell dimensions, a = 6.0330 Å, b = 7.3207 Å and c = 12.8374 Å. The electrochemical properties of the complex [Fe2(MPAAP)2CI6] were investigated by cyclic voltammetry. An octahedral structure is tentatively proposed for the complexes