Novel drug-based Fe(III) heterochelates: synthetic, spectroscopic, thermal and in-vitro antibacterial significance

A series of novel heterochelates of the type [Fe(A(n))(L)(H2O)(2)](center dot)mH(2)O [where H(2)A(n) = 4,4'-(arylmethylene)bis(3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-ol); aryl = 4-nitrophenyl, m = 1 (H(2)A(1)); 4-chlorophenyl, m = 2 (H(2)A(2)); phenyl, m = 2 (H(2)A(3)); 4-hydroxyphenyl, m = 2 (H(2)A(4)); 4-methoxyphenyl, m = 2 (H(2)A(5)); 4-hydroxy-3-methoxyphenyl, m = 1.5 (H(2)A(6)); 2-nitrophenyl, m = 1.5 (H(2)A(7)); 3-nitrophenyl, m = 0.5 (H(2)A(8)); p-tolyl, m = 1 (H(2)A(9)) and HL = 1-cyclopropyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid] were investigated. They were characterized by elemental analysis (FT-IR, H-1- & C-13-NMR, and electronic) spectra, magnetic measurements and thermal studies. The FAB-mass spectrum of [Fe(A(3))(L)(H2O)(2)](center dot)2H(2)O was determined. Magnetic moment and reflectance spectral studies revealed that an octahedral geometry could be assigned to all the prepared heterochelates. Ligands (H(2)A(n)) and their heterochelates were screened for their in-vitro antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Serratia marcescens bacterial strains. The kinetic parameters such as order of reaction (n), the energy of activation (E-a), the pre-exponential factor (A), the activation entropy (Delta S-#), the activation enthalpy (Delta H-#) and the free energy of activation (Delta G(#)) are reported. Copyright (C) 2009 John Wiley & Sons, Ltd.