Synthesis and spectral studies of coumarin derivatives as fluorescent probes towards Fe3+ and Cu2+

Abstract

Three novel coumarin derivatives have been designed and facilely synthesized, namely 6-[bis-(2-acetoxyethyl)aminomethyl]-4-methyl coumarin (BAMC), 4-(trans-4-methylformate-styryl)-6-[bis-(2-acetoxyethyl) aminomethyl]-coumarin (TSAC) and Trans-4-[2-(benzimidazole-2-substituted)vinyl]-6-methyl coumarin (TBVC). The synthesis route of the coumarin derivatives via various reactions including Pechmann, Wittig and substitution, three strategies are applied in the construction of the coumarin-based fluorescent probes, in view of the impact of the electronic push-pull effect, extended electronic conjugated system, and the strong fluorescence emission group, respectively. The compounds BAMC and TSAC are proved to be selective fluorescent probes to Fe³⁺ and Cu²⁺based on the intramolecular charge transfer mechanism. TBVC exhibits enhanced fluorescent emission in tetrahydrofuran offers the potential for the high-performance fluorescent probe. The relationship between the structure and the fluorescence mechanism of coumarin probes is explored.