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Prediction of Gas Chromatographic Retention Indices of Coumarins

Quantitative structure-retention relationships (QSRR) were used in this study to relate the chromatographic retention of different substituted coumarins to molecular structure. Different structural parameters were selected, such as topological, geometric, electronic, quantum-chemical and physico-chemical descriptors, in order to find an equation that fitted the chromatographic retention of these compounds. The method proposed by Dimov that classifies the descriptors in different groups in agreement with their values of correlation coefficients was analysed. Significant correlation equations were obtained with the following molecular descriptors: the total surface area (AT), the electrotopological state index (S(-o-)) of the oxygen in position 1 of coumarin, and the highest occupied molecular orbital energy (EHOMO), showing that the experimental retention, using stationary phases with low polarity, was related with the shape and electronic factors of the solutes. The models found have a good predictive ability as established by cross-validation r2cv values and thus, can be used to aid in the elucidation of the structure or the chromatographic retention of similar coumarins.