Analysis of complexation between new bidentate bis-NHC ligand and some metal cations at different temperature

Abstract

In this research, the determination and complexation process between 3,3'-(2,2'-(4-methyl-phenylenesulfonamido)bis(ethane-2,1-diyl))bis(1-benzyl-3H-benzo[d]imidazol-1-ium)dibromide with Ni2+, Zn2+, Pd2+, Ag+, and Hg2+ cations in the binary mixture of methanol (MeOH) and water (H2O) at different temperatures (15, 25, 35 and 45ºC) were studied using a conductometric method. The results show that the stoichiometry of the complexes in all binary mixed solvents for Ni2+, Zn2+, and Pd2+ were 1:1 (M:L), while in other cases 1:2 (M:L) and 2:1(M:L). The stability constants (log ) of complex formation have been determined by fitting molar conductivity curves using a computer program (GENPLOT). The obtained data shows that in the pure methanol solvent system, the stability order is Ni2+< Pd2+<Zn2+<Hg2+<Ag+ and the complexation process seems more stable in pure methanol in most cases. The thermodynamic parameters were determined conductometrically. The complexes in all cases were found to be enthalpy destabilized but entropy stabilized. The experimental data was tested by using an artificial neural network (ANN) program and was in good agreement with the estimated data.