Synthesis and characterization of isothiocyanato complexes of dioxotungsten(VI) with mannich base ligands: Precursors for the preparation of pure phase nanosized tungsten(VI) trioxide

Abstract

Six isothiocyanato complexes of dioxotungsten(VI) with Mannich base ligands having the formula [WO2(NCS)2L-L] (where L-L = N-[1-morpholinobenzyl] acetamide (MBA), N-[1-piperidinobenzyl] acetamide (PBA), N-[1-morpholino(-4-nitrobenzyl)] benzamide (MPNBB), N-[1-piperidino(-3-nitrobenzyl)] benzamide (PMNBB), N-[1-morpholino(-2-nitrobenzyl)] acetamide (MONBA) and N-[1-morpholino(-3-nitrobenzyl)] acetamide (MMNBA)) have been synthesized by the reaction of tetraisothiocyanatodioxotungsten(VI) anion with the ethanolic solution of the corresponding ligand in aqueous medium in the presence of HCl. The complexes have been characterized by elemental analyses, FTIR, 1H NMR, 13C NMR, DEPT, ESI mass spectra, TGA/DTA, molar conductivity measurements, electronic spectra, magnetic moment measurements, SEM and XRD. Finally, the ligands and the corresponding complexes have been tested against Agrobacterium sp BN-2A and it has been observed that complexes show enhanced activity as compared to the ligands. The complexes on calcination give rod-like WO3 nanoparticles.

Keywords

• Antibacterial activity
• Calcination
• Rod-like WO3