Novel drug‐based Fe(III) heterochelates: synthetic, spectroscopic, thermal and <i>in‐vitro</i> antibacterial significance

Abstract

Abstract A series of novel heterochelates of the type [Fe(A n )(L)(H 2 O) 2 ] • m H 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, 1 H‐ &amp; 13 C‐NMR, and electronic) spectra, magnetic measurements and thermal studies. The FAB‐mass spectrum of [Fe(A 3 )(L)(H 2 O) 2 ] • 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 (Δ S # ), the activation enthalpy (Δ H # ) and the free energy of activation (Δ G # ) are reported. Copyright © 2009 John Wiley &amp; Sons, Ltd.