Liyan Wang

Microwave-assisted Michael addition of 2-amino pyridine to chalcones under catalyst-free conditions

A microwave-assisted, convenient, efficient, and catalyst-free procedure is described for the synthesis of 1,3-diphenyl-3-(pyridin-2-ylamino)propan-1-one derivatives by Michael addition of 2-aminopyridine to the chalcones. Short reaction times, simple reaction, easy of product isolation, high yields, and clean work-up are the advantages of this method.

A off–on pH fluorescence probe derived from phenanthro[9,10-d]imidazol-fluorescein based on ESIPT and ICT

A novel pH fluorescence probe (PIF), derived from phenanthro[9,10-d]imidazole bound to the fluorescein, is designed and synthesized based on the intramolecular hydrogen bond and then its spectra properties are investigated. Probe PIF exhibits negligible fluorescence intensity at acidic pH condition due to ESIPT quenching caused by the formation of the intramolecular hydrogen bonds, and a significant fluorescence enhancement in neutral and weak alkaline environments because of the strengthened ICT process arose from the fracture of the intramolecular hydrogen bonds. The studies of UV–Vis and fluorescence spectra mean that probe PIF is able to respond linearly and reversibly over pH from 6.5 to 9.0 with pKa of 7.0. Moreover, the pH responses of probe PIF are stable and not disturbed by the common cations and anions. The possible response mechanism has been proposed according to the analysis of 1H NMR and DFT calculations.

Benzimidazole derivative fluorescent probe for cascade recognition of phosphate and iron ions in aqueous medium and its logic gate behavior

A fluorescent probe based on benzimidazole was synthesized, and its cascade recognition of PO43− and Fe3+ ions was investigated using spectroscopic techniques. This probe showed a highly sensitive and selective response towards PO43− and Fe3+ relative to other anions and metal ions. Moreover, the resulting [probe–PO43−] complex exhibited a turn-off response toward Fe3+ ion, leading to the fabrication of an INHIBIT logic gate using PO43− and Fe3+ ions as inputs and the emission of the probe as output. This research may enrich the field of multi-functional chemosensors in natural products.