Pyrimidine based highly sensitive fluorescent receptor for Al3+ showing dual signalling mechanism

Abstract

A new fluorescent probe (5-[(4-diethylamino-2-hydroxy-benzylidene)-amino]-1H-pyrimidine-2, 4-dione) (Receptor1) has been synthesized by the Schiff base condensation of 5-aminouracil with 4-(diethylamino)salicylaldehyde. The receptor 1 exhibits high selectively for Al³⁺ in DMSO as well as in aqueous solution even in the presence of biologically relevant cations such as Na⁺, K⁺, Ca²⁺, Mg²⁺, Pb²⁺ and several transition metal ions. The lowest detection limit for the receptor 1 was found to be 1.62 × 10⁻¹⁰ M with its linear response towards Al³⁺ in the concentration range of 1.75 × 10⁻⁹ to 3.3 × 10⁻⁸ M in DMSO. Receptor 1 is the first ever example where a single molecular probe is able to show imine (CN) isomerization inhibition along with twisted intramolecular charge transfer (TICT) in combinatorial fashion.