Synthesis, characterization, electrical and catalytic studies of some coordination compounds derived from unsymmetrical Schiff base ligand

Abstract

ABSTRACT. New unsymmetrical tetradentate Schiff base ligand derived from 5-chloro-2-hydroxyacetophenone, 2-hydroxy-5-methyl-3-nitro acetophenone and carbohydrazide and its complexes with VO(IV), Cr(III), Mn(III), Fe(III), MoO2(VI), WO2(VI), Zr(IV) and UO2(VI) have been prepared. They were characterized by elemental analysis, IR and electronic spectra, magnetic susceptibility measurements and thermal analyses. The Schiff base ligand has also been characterised by 1 H-NMR spectroscopy. The thermal behaviour of metal complexes shows that the hydrated complexes lose water molecules of hydration in the first and then is immediately followed by decomposition of ligand molecule in the subsequent steps. The IR spectra suggest that ligand acts as dibasic tetradentate nature and coordination takes place through azomethine nitrogen and phenolate oxygen. The crystalline nature of the VO(IV) complex was conformed through the powder XRD analysis. The catalytic activity of the VO(IV) and Mn(III) complexes have been tested in the epoxidation reaction of styrene and conversion of styrene were 11.14-24.35% and 9.64-23.42%, respectively. The solid state electrical conductivity of ligand and its complexes were measured, which could obeyed the relation  =  0 exp (Ea/KT) over the temperature range 313-413 K.

Synthesis, Antibacterial Activity and DFT Calculations of Some Thiazolidine-4-Carboxylic acid Derivatives and Their Complexes with Cu(II), Fe(II) and VO(II)

“…At 570 and 620 nm, two peaks were exhibited in the visible region of VO(II) complexes for VO(L 1 ) 2 , while at 570 and 730 nm for VO(L 2 ) 2 , which could also be due to transitions 2 B2 → 2 B1 and 2 B2 → 2 E, respectively. As per these assignments, VO(II) complexes are associated with square pyramid structure [21], and the magnetic moment values were 1.59 and 1.68 B.M for complexes, which denote one unpaired electron in d-orbital.…”