MOLECULAR TOPOLOGY AND QUANTUM-CHEMICAL DESCRIPTORS IN THE STUDY OF REVERSED-PHASE LIQUID-CHROMATOGRAPHY - HYDROGEN-BONDING BEHAVIOR OF CHALCONES AND FLAVANONES

The reversed-phase liquid chromatographic hydrophobicity parameters (l og K'(w) and S) of several chalcones and flavanones were determined wi th methanol:water mobile phases of different compositions and with tra ce quantities of n-decylamine and l-octanol added to the eluent to min imize the silanophilic interactions present in alkylsilane-bonded phas es. It has been reported that qualitative hydrogen bonding information can be obtained from the relationship between Sand log K'(w) determin ed with these chromatographic conditions. To quantitatively describe t he hydrogen-bonding discrimination effects observed for the compounds under study, the parameter Delta was defined as follows: Delta((s-log) (kappa w)) = S- log K'(w). With topological and molecular orbital cal culations, several molecular descriptors were computed for test compou nds, and multivariate statistical techniques were used to examine the informative value of the parameter proposed. The results obtained indi cate that Delta((s-log) (kappa w)) encodes structural information main ly related to the molecular polarity and the ability of compounds to p articipate in hydrogen-bonding interactions. Similar structural inform ation was also obtained for Delta((s-log) (kappa w)) values of 31 stru cturally dissimilar compounds.