QSPR Analysis of Phenylthio Phenylsulfinyl and Phenylsulfonyl Esters Using Quantum Chemical Semi‐Empirical Descriptors

Abstract

AbstractQuantitative structure‐property relation ships (QSPR) were developed with the quantum semiempirical descriptors computed by AM1 Hamiltonian in MOPAC7.0 for phenylthio, phenylsulfinyl and phenylsulfonyl esters. Using step wise regression analysis with a cross‐validation procedure, the most potent and in formative descriptors were screened out from a group of 19 quantum chemical semi‐empirical descriptors, including steric and electronic types, to build QSPR models. Several equations were obtained and used to estimate and predict octanol/water partition coefficients and reversed phase high‐performance liquid chromatography (HPLC) capacity factors for a series of 30 similar sulfur‐containing compounds. The results indicate that molecular descriptors, including average molecular polarizability (α), energy of the lowest unoccupied molecular orbital (ELUMO), net atomic charge on carbon atoms in the carbonyl (QCO), molecular weight (MW), the most positive atomic charge on hydrogen atom (QH+), and net atomic charge on oxygen atoms in the group‐NO2 (QNQ2) are the main factors affecting the octanol/water partition coefficients of the compounds under study. And quantum descriptors, covering the most negative atomic charge on an atom Q−), net atomic charge on carbon atoms in the carboxy (QCOO), molecular weight (MW), heat of formation (HF), the most positive atomic charge on a hydrogen atom (QH+), and total energy (TE), are the main factors affecting HPLC capacity factors of these compounds. Rational mechanisms for the two physico‐chemical proper ties of the sulfur‐containing carboxylates were discussed and interpreted.