Evaluation of chiral recognition ability of a novel uranyl-salophen-based receptor: an easy and rapid testing protocol.

Abstract

A novel member of a new class of chiral uranyl-salophen complexes has been synthesised. The chiral recognition ability of this receptor toward the enantiomers of two primary amines, a sulfoxide, and a quaternary ammonium chloride has been evaluated for the first time. The enantioselectivities obtained are encouraging. The NMR method developed for this purpose allows a fast, quantitative determination of the enantioselectivity of the host directly from its racemic mixture and could find application as a preliminary screening tool in the search for new receptors using combinatorial methods. The experiments carried out in this context demonstrated also that the activation barrier for the racemisation of such chiral uranyl-salophen receptors is much higher than the lower limit of 21 kcal mol(-1) previously reported.