Synthesis and characterization of some arylhydrazone ligand and its metal complexes and their potential application as flame retardant and antimicrobial additives in polyurethane for surface coating

Hydrazones are versatile organic ligands and can be synthesized by condensation of hydrazides with carbonyl compounds (aldehydes/ketones). These compounds coordinate to the metal ions via azomethine nitrogen. Hydrazone Schiff's base ligands and their transition metal complexes possess a number of biological and flame retardant applications. Some selected divalent metal (Cu-II and Ni-II) complexes of hydrazone Schiff base ligand, namely o-methoxybenzaldehyde benzoylhydrazone (MBH) was synthesized and fully characterized by elemental analysis, FTIR, (1) HNMR and mass spectra. This work summarizes the application of the prepared MBH ligand and its metal complexes. The prepared MBH ligand and its metal complexes were physically incorporated in polyurethane coating and evaluated for their flame retardancy and antimicrobial activity for surface coating. The flame retardancy of these materials was characterized by the limiting oxygen index (LOI) test. The antimicrobial activity of these materials was screened against Gram-positive bacteria, Gram-negative bacteria and fungi. The physical, mechanical and chemical properties were studied to ascertain any drawbacks. On the basis of experimental results of an oxygen index (LOI) and the biological activity, the synthesized MBH ligand and its metal complexes showed excellent flame retardancy and antimicrobial activity. In addition, the metal complexes were much more active than the original MBH ligand. Quantum chemical calculations were also performed by Semiempirical PM3 method to find the optimum geometry of the ligand and its metal complexes. The calculated pharmacokinetic parameters in silico, showed promising futures for application of the MBH ligand and its metal complexes as high antimicrobial potency agents. (C) 2015 Elsevier B.V. All rights reserved.