High-contrast multicolour photoswitching based on dithienylethene Schiff base with a hydrazinylquinoline moiety

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 308; p. 123679
• Main Authors: Wang, Renjie, Li, Mengyuan, Li, Gang, Pu, Shouzhi
• Format: Journal Article
• Language: English
• Published: England 05.03.2024
• Subjects: Chemosensor; Diarylethene; Zn(2+)/Cd(2+) recognition; Photochromism; Fluorescent switch
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2023.123679

A new asymmetrical photochromic diarylethene DTE-HQo composed of a 2-hydrazinoquinoline moiety as the binding unit for ions and dithenylethene as a photoswitching trigger was reported. DTE-HQo displayed favourable photochromism upon irradiation with UV/vis light. Its fluorescent behaviour could be efficiently modulated by light, Zn , Cd and HSO . The binding of Zn induced a strong fluorescence peak at 510 nm in DTE-HQo due to the formation of a 1:2 complex [Zn + 2DTE-HQo], resulting in a notable colour change from dark to intense white emission. Triggered by Cd , DTE-HQo formed a 1:1 complex [Cd + DTE-HQo], leading to an enhanced emission intensity by 21-fold with an emission peak red-shifted from 461 nm to 514 nm. Unexpectedly, [Zn + 2DTE-HQo] underwent hydrolysis when stimulated with water, generating a yellow-emitting complex [Zn + DTE-HQo]. This color change easily distinguishes it from Cd complex. Additionally, DTE-HQo showed high selectivity towards HSO and exhibited distinct "turn-on" fluorescence with a colour change from dark to bright blue upon stimulation. Moreover, the strong emission complexes of DTE-HQo with Zn , Cd and HSO could be effectively quenched during the photocyclization process. Therefore, DTE-HQo can serve as an unimolecular multicolour photoswitching chemosensor, offering potential applications as a multifunctional probe for detecting Zn , Cd and HSO .