Metallic ion sensing with a benzothiazole-based fluorimetric chemosensor

An unnatural amino acid derivative, N-tert-butyloxycarbonyl asparagine benzyl ester bearing a benzothiazole unit at the side chain, was evaluated as fluorimetric chemosensor for several transition metal cations with environmental, biological and analytic relevance. Spectrofluorimetric titrations of the heterocyclic asparagine derivative with the various ions were carried out in acetonitrile and acetonitrile/water (9:1). It was found that the unnatural amino acid had a remarkable fluorimetric response in the presence of Cu2+ in acetonitrile and in the presence of Fe3+ in acetonitrile/water (9:1).Thanks are due to Fundação para a Ciência e Tecnologia (Portugal) and FEDER-COMPETE for financial support through Centro de Química (UID/ QUI/0686/2016).