Sheshashena Reddy T, Moon H, Choi MS. Turn-on fluorescent naphthalimide-benzothiazole probe for cyanide detection and its two-mode aggregation-induced emission behavior.
SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021;
252:119535. [PMID:
33582439 DOI:
10.1016/j.saa.2021.119535]
[Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/13/2021] [Accepted: 01/22/2021] [Indexed: 06/12/2023]
Abstract
Naphthalimide-benzothiazole conjugate (NBTZ) linked by cinnamonitrile was designed, synthesized, and fully characterized by NMR (1H, 13C, DEPT, HSQC) and high-resolution mass spectrometry. NBTZ exhibited unique turn-on fluorescence in the presence of CN- with relatively high selectivity compared to other anions such as SCN-, HSO4-, ClO4-, NO3-, Cl-, Br-, I-, and PO4-3 in tetrahydrofuran (THF). The detection limit for CN- was found to be 3.35 × 10-8 M in THF. The sensing mechanism was analyzed through 1H, 13C, DEPT, and mass spectroscopy. NBTZ also showed two-mode aggregation-induced emission (AIE) in THF-H2O mixtures. In a 30:70 THF-H2O (v/v) mixture, the maximum AIE was observed at 430 nm (blue) because of the rotation of the CC bond between the naphthalimide ring and the phenyl ring was restricted. In 10:90 THF-H2O (v/v), a new red-shifted AIE appeared at 490 nm (cyan), due to the extended π-conjugation induced by restriction of rotation of the CC bond between the benzothiazole and naphthalimide rings.
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