Heteroditopic chiral uranyl-salen receptor for molecular recognition of amino acid ammonium salts

A new heteroditopic chiral uranyl–salen complex incorporating two pyrenyl groups was designed and synthesized for the recognition of ammonium salts, tetrabutylammonium (TBA) and tetramethylammonium (TMA) amino acids. UV/Vis measurements indicate the formation of 1:1 host–guest complexes with high association constants and an excellent enantiomeric discrimination between the two enantiomers of phenylalanine–TMA. T-ROESY NMR experiments confirm cation–π and CH–π interactions between the TBA and TMA cations and the two pyrenyl arms, leading to the strong stability of the complexes. This is the first report of a uranyl receptor able to recognize chiral carboxylate guests.

A new heteroditopic chiral uranyl-salen complex incorporating two pyrenyl groups was designed and synthesized for the recognition of ammonium salts, tetrabutylammonium (TBA) and tetramethylammonium (TMA) amino acids. UV/Vis measurements indicate the formation of 1:1 host-guest complexes with high association constants and an excellent enantiomeric discrimination between the two enantiomers of phenylalanine-TMA. T-ROESY NMR experiments confirm cation-pi and CH-pi interactions between the TBA and TMA cations and the two pyrenyl arms, leading to the strong stability of the complexes. This is the first report of a uranyl receptor able to recognize chiral carboxylate guests.