Synthesis, Characterisation and Biological Activity of Polymeric Metal Complexes Derived from Multidentate Ligand

Abstract

New Schiff-base ligand and their polymeric metal complexes with Cr(Ш), Mn(II), Fe(II),Co(II),Ni(II) and Cu(II) ions are reported. Ligand was prepared in two-step reaction. The reaction of 2-hydroxy-5-methylisophthalaldehyde with 3-Amino-1-propanol resulted in the isolation of precursor (3,3'-((1E,1'E)-(propane-1,3-diylbis (azanylylidene)) bis (methanylylidene)) bis (2-hydroxy-5-methylbenzaldehyde)).The reaction of precursor with acrylamide gave the required ligand; (N,N'-((1E,1'E)-(((1E,1'E)-(propane-1,3-diylbis (azanylylidene)) bis (methanylylidene)) bis (2-hydroxy-5-methyl-3,1-phenylene)) bis (methanylylidene)) diacrylamide) H2L. The reaction of this ligand with the appropriate metal ions gave polymeric metal complexes of the formulae {[M2(L)Cl2]. Cl2H2O} n M=Cr(Ш), {[M2(L) (H2O)2]. Cl2} n M=Mn (II) Ni (II), {[M2(L) (H2O) Cl] Cl} nM=Fe (II), {[M2(L)Cl2]. H2O} n, M= Co (II), Cu (II). A range of techniques was used to confirm the entity of ligand and their complexes. The formation of ligand and mode of complexation and geometrical structure of the title polymeric complexes were verified using FTIR, electronic spectra, NMR, ESMS, magnetic susceptibility, micro-elemental analysis, metal content, chloride content and conductance. The analytical and spectroscopic data indicated the formation of six-coordinate complexes. Biological evaluation of ligand and their polymeric complexes against gram-positive bacteria (G+), Bacillus stubtili, Staphylococcus aureus, and gram-negative bacteria (G−), Escherichia coli and Pseudomonas aeruginosa and compared with antibiotic drug (Cefotaxime) and two types of fungi namely (Candida albicans and Rhizopus sporium) and compared with the activity of fungal agent (Fluconazole).The collected data revealed the antimicrobial activity of the ligand was enhanced upon complex formation.