Dependence of an Anion Template on Amino Acid Binding in DMSO/H2O by a Chiral Ag/Urea-Based Tweezer

Abstract

A chiral "dual-tweezer" compound containing anion-binding pockets, {[Ag(MeBzUTh) 2 ]} 2 (CF 3 CO 2 ) 2 , has been prepared and shown to bind both alanine and phenylalanine in DMSO/H2Osolution. The trifluoroacetate counter-anion gives enhanced binding through a template effect compared to other species. Interactions between the guest carboxylate and both the urea groups and the argentophilicly bound Ag 2 core drive binding, with selectivity achieved through a sterically protected pocket defined by chiral methylbenzyl units giving a more pronounced 1 H NMR response for phenylalanine.