Hao X, Han S, Zhu J, Hu Y, Chang LY, Pao CW, Chen JL, Chen JM, Haw SC. A bis-benzimidazole PMO ratiometric fluorescence sensor exhibiting AIEE and ESIPT for sensitive detection of Cu
2.
RSC Adv 2019;
9:13567-13575. [PMID:
35519599 PMCID:
PMC9063946 DOI:
10.1039/c9ra00892f]
[Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 04/14/2019] [Indexed: 01/06/2023] Open
Abstract
A novel bis-benzimidazole organic siloxane precursor (BBM-Si) was prepared, and was combined with tetraethylorthosilicate (TEOS) as a mixed Si source. Then, bridged periodic mesoporous organosilica (BBM-PMO) spherical nanoparticles were synthesized by co-condensation using cetyltrimethylammonium bromide (CTAB) as structure directing agent. The optical properties showed that BBM qualifies as an "aggregation induced emission enhanced" (AIEE) molecule, exhibiting characteristics of excited-state intramolecular proton transfer (ESIPT), such as a large Stokes shift and dual fluorescence emission. For the BBM-PMO materials, the silica skeleton provides a rigid environment that limits molecular rotation, resulting in improved fluorescence emission. In particular, the BBM-PMOs exhibited dual emission of the enol and keto forms, achieving a ratiometric response to Cu2+ with high sensitivity and selectivity in a broad pH range. Additionally, the limit of detection was as low as 7.15 × 10-9 M in aqueous solution. The X-ray absorption near-edge spectroscopy (XANES) showed the coordination structure through the interaction between copper ions and N atoms of benzimidazole in the BBM-PMO coordinated to Cu2+. These results demonstrate that BBM-PMO hybrid materials have potential applications in the fields of bio-imaging and environmental monitoring.
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