Physico-chemical and biological studies of some Copper(I) complexes in binary mixtures of polar solvents at variable temperature

Abstract

Physico-chemical parameters like, conductance, viscosity, volumetric, thermo acoustic, thermodynamics of viscous flow, were thoroughly evaluated from the experimentally obtained data of specific conductance, viscosity, density, and ultrasonic velocity. These parameters were evaluated for Copper(I) nitrate complexes in binary mixtures of polar solvents, Dimethylsulfoxide (DMSO), Pyridine (Py), and Nitromethane (NM) at variable temperatures (298 K-318 K) and at 1 atmospheric pressure. Ionic B values were evaluated using Jones-Dole equation to determine the extent of molecular interactions. From the measured viscosity, using Erying's transition state theory, the thermodynamic parameters of viscous flow such as Gibb's energy of activation (ΔG)*, enthalpy of activation (ΔH)*, and entropy of activation (ΔS)* were also evaluated. The thermodynamic function showed the values of ΔH* as positive for all electrolytes and ΔS* as negative. From the conductance data, the Energy of Activation (Ea) and ionic walden product (λoη) were evaluated and tabulated. Further, in order to discover more about the solute–solvent interactions, limiting apparent molar volume (ɸ˚v), Masson’s coefficient (Sv), partial molar expansibilities (ɸ˚E) and Hepler’s constant were also calculated from density and velocity data at variable temperatures. Limiting apparent molar volume ɸ˚v values for both binary mixtures were positive, indicating strong solute–solvent interactions. Thermo acoustical parameters like internal pressure (πi), Rao’s constant (Rm) and Wada’s constant (W) were also evaluated. The results from all the studies showed the possible solvation in DMSO + Py solvent mixture as compared to DMSO + NM system. Further, the copper(I) nitrate complexes with bioactive ligands were tested against Gram positive strains (S mutans MTCC 497 and S aureus MTCC 7443), Gram negative strains (S enteric MTCC 164 and P aeruginosa MTCC 4673) and fungus (A parasiticus NCIM 696, Candida albicans MTCC 183 and A niger NCIM 501). The zone of inhibition was also measured for the complexes. All the complexes with potential bioactive ligand containing Nitrogen and Sulphur atom bonded to central copper atom showed antibacterial and antifungal activity.