Recognition mechanism of aromatic derivatives resolved by argentation chromatography: The driving role played by substituent groups

Abstract Argentation chromatography is widely used nowadays as a powerful tool to separate complex mixtures of analytes containing unsaturated and/or aromatic fragments. Here we present the results of chromatographic and computational studies on a silver-thiolate stationary phase, in which the silver metal is covalently bonded to mercaptopropyl silica particles. The exceptionally high selectivity displayed by this organometallic moiety prompted us to deeply investigate its molecular recognition properties. The interactions of the silver atom with a series of benzene derivatives was investigated to gain information on the mechanism by which the different ring substituents modulate retention factors and selectivity. The experimental trend was fully rationalized by means of quantum-mechanical Density Functional Theory (DFT) calculations, which allowed us to elucidate the chromatographic results in the light of unusual and unexpected substituent effects.