Spectroscopic and DFT studies of the charge transfer complexation of iodine with aniline and its derivatives in carbon tetrachloride medium

The charge-transfer (CT) complex formation of iodine with aniline and derivatives of aniline in CCl4 at numerous temperatures (293.15–308.15 K) has been investigated by UV–Visible spectroscopy and density functional theory (DFT) methods. The formation constant (KCT) of the CT complexation was determined by using the Benesi-Hildebrand plot. The KCT values of CT complexes amid iodine and aniline/aniline derivatives were found to be changed with temperature variation and the change of the structure of donor molecules. Thermodynamic parameters such as ΔG0, ΔH0, and ΔS0 of CT complexes were calculated from the standard thermodynamic equations. The ΔG0 values are negative, which indicates the spontaneous nature of CT complexation. The ΔH0 and ΔS0 values for the iodine-aniline/ derivatives of aniline indicated that the CT complexation is happened due to hydrophobic and exothermic interactions. The additional CT band has appeared in the UV spectra from experimental and DFT studies. Besides, the interaction between the I2 and aniline/ derivatives of aniline was detected by the elongation of bond length of I2 acceptors. Also, other parameters associated with the CT complexes have been evaluated and described in detail.