Ligational behaviour of two biologically active N?S donors towards cobalt(III), iron(III), iron(II) and rhodium(III)

Abstract

The chelating behaviour of two biologically active ligands, pyridine-2-carboxaldehyde(4-phenyl) thiosemicarbazone(L1H) and pyridine-2-carboxaldehyde thiosemicarbazone(LH), towards FeIII, CoIII, FeII and RhIII has been investigated. The ligands act as tridentate N−N−S donors, resulting in the formation of bis-chelate complexes of the type MIII(A)2X·nH2O (A=L1 or L; X=Cl, ClO4; M=CoIII, RhIII, FeIII), FeII(L1H)2SO4·2H2O and FeII(L1)2·H2O. Biological activity of the ligands and the metal complexes in the form ofin vitro antibacterial activities towardsE. coli has been evaluated and the possible reasons for enhancement of the activity of ligands on coordination to metal ion is discussed.