Experimental and computational spectroscopic study of ibuprofen and their synthesis precursors

Abstract

In this research, infrared (IR) and ultraviolet/visible spectra (UV/VIS) of ibuprofen, 4-isobutylacetophenone and isobutylbenzene obtained experimentally were compared with the spectra obtained computationally. The research comprises of two stages. In the first one, ibuprofen was experimentally synthetized and its precursors isolated. In the second phase, the electronic structural modeling program GAUSSIAN 03 was used in order to obtain molecular optimization of all structures of interest and their spectroscopic properties. The experimental spectra were compared with the computational ones, obtaining error rates between 2 and 28 % in both spectroscopy methods. The main difference was due to the aggregation state in which the spectra were obtained, liquid and solid in the case of the experimental spectra, and gaseous for computational spectra. Computational spectra are fully comparable with those obtained experimentally proving to be quite accurate. This proves the applicability of the computational methods in the synthesis and design of new drugs.