Bioinspired non-aromatic compounds emitters displaying aggregation independent emission and recoverable photo-bleaching

• Published in: Talanta (Oxford) Vol. 206; p. 120232
• Main Authors: Xu, Cui, Guan, Ruifang, Cao, Duxia, Liu, Kaerdun, Chen, Qifeng, Ding, Yunqiao, Yan, Yun
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2020
• Subjects: Aggregation independent fluorescence emission; Intramolecular hydrogen bonds; Nonaromatic fluorescent molecule; Probe for Hg2; Nonaromatic fluorescent molecule; Probe for Hg2; Intramolecular hydrogen bonds; Aggregation independent fluorescence emission; Probe for Hg(2+)
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2019.120232

Aggregation dependence is a universal feature for fluorophores, ranging from classical planar fluorescent dyes displaying aggregation-caused quenching (ACQ) and propeller-shaped AIEgens that exhibit aggregation-induced emission (AIE). In this work, we report compounds emitters (CA-PDA) that display aggregation-independent fluorescence owing to the formation of robust intramolecular, rather than intermolecular hydrogen bonding. We achieved CA-PDA by synthesis of an amide from citric acid (CA) and propane diamine (PDA). Quantum chemistry calculations suggest the CA-PDA compounds have closed structures facilitated by intramolecular hydrogen bonds, which forces the lone pair electrons on oxygen and nitrogen to within 2.9 Å. Then the strong electron clustering generates a pseudo conjugated effect and leads to blue emission. This emission exhibits recoverable photobleaching, as UV irradiation only temporally breaks the intramolecular hydrogen bonds, which may form again upon relaxation. CA-PDA can be used in cell imaging as well as in probes for Hg2+ and sulfur-containing amino acids. We expect that the strategy of a bioinspired intramolecular hydrogen bonds-facilitated compounds emitters will provide a new avenue toward advanced fluorescent materials. [Display omitted] •The fluorescent compounds emitters CA-PDA were synthesized of an amido from citric acid (CA) and propane diamine (PDA).•CA-PDA displays aggregation independent fluorescence owing to the formation of intramolecular, rather than intermolecular, hydrogen bonds.•Quantum chemistry calculations suggest intramolecular hydrogen bonds of CA-PDA stabilize the distance between oxygen and nitrogen atoms, then lone pairs of electrons on oxygen and nitrogen clustering together generate a pseudo conjugated effect and lead to blue emission.•UV irradiation only temporally breaks the intramolecular hydrogen bonds of CA-PDA, which may form again upon relaxation.•CA-PDA can be used in cell imaging as well as in sensors for Hg2+ and sulfur-containing amino acids.