Benzimidazole Conjugate of 1,1′-Thiobis(2-naphthol) as Switch-On Fluorescence Receptor for Ag⁺ and the Complex as Secondary Recognition Ensemble toward Cys, Asp, and Glu in Aqueous Methanolic Solution: Synthesis, Characterization, Ion and Amino Acid Recognition, Computational Studies, and Microscopy Features

Abstract

A new 1,1'-thiobis(2-naphthoxy)-based receptor molecule (L) containing a benzimidazole moiety has been synthesized and characterized by (1)H NMR, ESI-MS, and elemental analysis. The selectivity of L has been explored in aqueous methanol, resulting in selective (7.5 ± 0.5)-fold switch-on fluorescence response toward Ag(+) among 14 different transition, alkali, and alkaline earth metal ions studied. The complexation of Ag(+) by L has been addressed by ESI-MS, (1)H NMR, and UV-vis spectra. Microstructural features of L and its Ag(+) complex have been measured by AFM and TEM. The morphological features of L alone and L in the presence of Ag(+) differ dramatically both in shape and size, and the ion induces the formation of chains owing to its coordinating ability toward benzimidazole. Further, the in situ [Ag(+)-L] complex was titrated against 20 naturally occurring amino acids and found that this complex acts as a secondary recognition ensemble toward Cys, Asp, and Glu by switch-off fluorescence.

Silver (I)-coordinated bis(trimethoxysilylpropyl)amine Polycondensate for Adsorptive Removal of Iodide from Aqueous Solutions

“…In light of previous research on complexation between Ag + and amino-containing compounds [18][19][20][21], we inferred that AgNO 3 could dissolve into TSPA. Furthermore, the FTIR analyses of TSPA gel and TSPA-AgNO 3 gel displayed in Fig.…”

A 1,3‐Capped Calix[4] Conjugate Possessing an Amine Moiety as an Anion Receptor: Reversible Anion Sensing Detected by Spectroscopy and Characterization of the Supramolecular Features by Microscopy

“…Calixarenes are known to show distinctive supramolecular features in the presence of different cations, anions, or molecules when placed on surfaces and studied by microscopy . The supramolecular characteristics of L amino and its anion adducts were studied by SEM.…”

“…Calixarenes are known to show distinctive supramolecular features in the presence of different cations, anions, or molecules when placed on surfaces and studied by microscopy. [58][59][60][61] The supramolecular characteristics of L amino and its anion adducts were studied by SEM. The L amino sample shows discrete spherical particles of 200-500 nm (Figure 7a,b ,o ,a nd p), and the features are the same, regardless of whether the molecule was taken in acetonitrile or ethanol.…”

A highly selective TPE-based AIE fluorescent probe is developed for the detection of Ag+

“…Compound 1 was synthesized as previously reported. 58 Zinc powder (1.0 g, 15.3 mmol) was added into a 100 mL double-neck ask. Under an N 2 atmosphere, 25 mL anhydrous THF was added, cooled to À5 C, and then TiCl 4 (1.1 mL, 10 mmol) and pyridine (0.05 mL, 0.6 mmol) were added dropwise.…”