Using theoretical descriptions in structure activity relationships: retention indices of sulfur vesicants and related compounds

We have conducted a theoretical linear solvation energy relationship (TLSER) investigation of gas chromatographic (GC) retention indices for a series of 37 organosulfur compounds on three different columns, deriving regression equations based on descriptors obtained using the MNDO, AM1 and PM3 Hamiltonians. In all cases, satisfactory regressions based on two or three descriptors result, with molecular volume being the most important descriptor. Our results are qualitatively similar to those of Woloszyn and Jurs who, considering the same sulfur vesicant GC retention data set, applied an objective feature selection procedure to winnow descriptors from an initial set of 100, but were not able to treat any compounds containing sulfur–sulfur bonds. Our approach was free of this restriction, allowing for consideration of all 37 compounds. Only relatively small differences were obtained in the statistical quality of the regressions derived from the three Hamiltonians considered, and among the three GC columns.