JOURNAL OF APPLIED SPECTROSCOPY, vol.88, no.4, pp.855-862, 2021 (SCI-Expanded)
The solvent effects on C=O stretching vibrational frequency, nu(C=O), of ketoprofen (KETO) were studied experimentally using attenuated total reflection infrared spectroscopy (ATR-IR). The experimental nu(C=O) of KETO were correlated with empirical solvent parameters, including the Kirkwood-Bauer-Magat (KBM) equation, the acceptor numbers (ANs) of the solvents, the Swain equation, linear solvation energy relationships (LSERs), and the quadratic equation (QE). The solvent-induced nu(C=O) shifts of KETO displayed a better correlation with the LSER equation than with the KBM equation, ANs of the solvents, and the Swain equation. The linear effect of the solvent hydrogen-bond donor acidity (A(j)) on nu(C=O) of KETO was found to be highly significant, whereas the hydrogen-bond acceptor basicity (B-j) and the interaction effect of A(j) and B-j were not significant. It was also observed that the quadratic effects of A(j) and B-j were slightly significant. Additionally, the linear effect of LSER parameters (pi*, delta, alpha, and beta) and the interaction effect of pi*beta on the nu(C=O) of KETO were highly significant.