This study offers insights to predict relative liquid-phase cation-p binding energies (Ebind) based on the aromatic substitution pattern. In addition, the study allows for comments on the intermolecular forces (electrostatics, induction and dispersion) that contribute most to the overall Ebind. The research involved characterizing interactions between an ionic chromatographic stationary phase and neutral aromatic molecules on the basis of multiple solvation interactions. We employed liquid chromatography and Abraham's linear free-energy relationship (LFER) model to experimentally characterize and categorize the different intermolecular forces contributing to cation-arene interactions. Both electron withdrawing and donating mono, 1,2-di, 1,3,5-tri and 1,2,4,5-tetra substituted aromatics, and aliphatic compounds for controls, were passed through either a strong or weak cation exchange column. The solutes' retention times and descriptors were applied in a multiple linear regression analysis (MLRA) and used to determine the interaction parameter coefficients for the stationary phase. We will report which coefficients are dominant in the resulting correlation equations relating the retention times to the Abraham constants. Furthermore, we will discuss which intermolecular forces are represented by the dominant Abraham constants, thus defining the intermolecular forces most responsible for the cation-arene binding.

Cation-exchange chromatography as a means to study cation-arene binding interactions

247th National Meeting (2014)

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