Studying intermolecular interaction of thiophene-2-carboxylic acid in chloroform solutions

The spectral bands of pure 2-thiophene carboxylic (TCA) acid in chloroform solution (TCM)were studied over a wide range utilizing Raman and FTIR spectroscopy. The maxima of theC=O, O-H, C-H stretching, and C-H breathing vibration bands in the TCA solution with TCMred-shifted or blue-shifted. This suggests that H-bonding, van der Waals (vdW) interactions,and hyper-conjugation interactions are common in solutions. MEPS, HOMO and LUMO,AIM, NCI, RDG, ELF, and LOL investigations were carried out with a quantum chemicalcomputational technique based on density functional theory (DFT). When TCA is complexedwith TCM, the potential surrounding the TCA oxygen decreases, as shown by the yellow color, indicating that TCA-TCM complexes are formed predominantly by weak H-bonds.TCA-TCM complexes exhibit weak H-bonding or vdW interactions, according to AIM, NCI,and RDG studies.