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

•A charge-transfer complex was synthesized and confirmed by spectral investigations.•Spectroscopic studies were performed in different polar solvents acetone and methanol.•X-ray Diffraction studies confirmed the crystal structure and nano range of the CTC.•Spectroscopic studies reveal the formation of 1:1 CTC associated with proton transfer from A to D.•TGA–DTA analyses were performed to further confirm the thermal degradation of the CTC.

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.

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