A fluorescence probe based on 6-phenylimidazo[2,1-b]thiazole and salicylaldehyde for relay discerning of In3+ and Cr3+
A new fluorescence probe (E)-N′-(2-hydroxybenzylidene)-6-phenylimidazo[2,1-b]thiazole-3-carbohydrazide (LB1) based on 6-phenylimidazo[2,1-b]thiazole and salicylaldehyde was designed and synthesized. Chemical structures of LB1 and its intermediate were characterized by 1H NMR, 13C NMR spectra, FTIR, and mass spectrum. The probe LB1 exhibited high sensitivity and selectivity towards In3+ and Cr3+ via a fluorescence ‘off-on-off’ response. The detection limit of In3+ and Cr3+ was 2.59 × 10-9 M and 8.05×10-7 M, respectively. It was found that the probe LB1 performed ideal selectivity for In3+ among other competing ions and the new formed complex [LB1+In3+] could be further used as a new fluorescence platform towards Cr3+. The Job’s Plot of LB1 towards In3+ and Cr3+ was 1:1, respectively and was identified by mass spectrum. The plausible binding modes and mechanisms were calculated through DFT/TDDFT calculations using Gaussian 09.