title: 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.
authors: Bioinorganic Laboratory, Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
authors: Jayaraman
authors: J
authors: Dessingou
authors: Atanu
authors: A
authors: Mitra
authors: Khatija
authors: K
authors: Tabbasum
authors: Garima Singh
authors: GS
authors: Baghel
authors: Chebrolu P
authors: CP
authors: Rao
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D001224:Aspartic Acid / Q000737:chemistry*; D001562:Benzimidazoles / Q000138:chemical synthesis* / Q000737:chemistry; D003545:Cysteine / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D018698:Glutamic Acid / Q000737:chemistry*; D007477:Ions / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D000432:Methanol / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D014867:Water
chemical_list: D000596:Amino Acids; D001562:Benzimidazoles; D005456:Fluorescent Dyes; D007477:Ions; D012996:Solutions; D014867:Water; D001224:Aspartic Acid; D018698:Glutamic Acid; D012834:Silver; D003545:Cysteine; D000432:Methanol