An Exploration of Ferrocenyl Ureas as Enantioselective Electrochemical Sensors for Chiral Carboxylate Anions

The syntheses of a series of chiral ureas containing the redox-active ferrocene group are described. Each of these bind chiral carboxylates in organic solvents through hydrogen-bonding interactions, as evidenced by spectroscopic and cyclic voltammetry measurements, the latter allowing these guests to be electrochemically sensed in solution. The enantioselectivity in the complexation of the protected amino acid N-benzenesulfonylproline by a ferrocenylbenzyl host is high enough to allow opposite enantiomers to be distinguished by electrochemical means.