Synthesis, spectroscopic studies and thermal analysis of charge-transfer complex of 2,2′-bipyridine with 4-hydroxybenzoic acid in different polar solvents

The charge-transfer (CT) complex formed between 2,2′-bipyridine with 4-hydroxybenzoic acid has been studied in methanol and acetone at room temperature. The charge-transfer complex was characterized on the basis of FT-IR, 1H NMR, XRD studies of the solid CT complex, UV–Visible spectroscopy, thermogravimetric analysis (TGA–DTA) and conductivity and the results were discussed. The particle size and the energy of the charge-transfer complex were also determined. The data obtained from the spectroscopic studies indicate the formation of 1:1 charge-transfer complex, associated with a proton migration from the acceptor to the donor followed by intermolecular hydrogen bonding. The conductivity was found to increase with increase in the concentration of the donor.