Catechol Moiety Integrated Tri‐Aryl Type AIEgen for Visual and Quantitative Boronic Acid Detection

Abstract

Novel functional AIEgen based on three compact bound aryl skeletons is designed and synthesized. This tri‐aryl type luminogen (TA‐Catechol) embedded with catechol moiety responds rapidly to series of boronic acids. Real‐time visual and quantitative dual‐mode detection method is established for the first time with modest precision and low detection limit (8.0 μM). Detailed mechanistic discussion identifies tetra‐coordinated boronic species as the key intermediate within sensing procedure. Wide range of organic boronic acids compatible with this strategy is displayed which is promising in high throughput screening technology. Furthermore, solid‐state sensing capability of TA‐Catechol is also demonstrated.

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“…This behavior agrees with our fundamental understanding of the AIE effect. We could ascribe this abnormal aggregate-state emissive property to the restriction of intramolecular motion (RIM) in solid state according to our previous work 40 and generally accepted theory. [50][51][52] And we expect this property could contribute to the detection process in the binary solvent with the specific water content.…”

“…Based on the tetra-coordinated boron-intermediated three-component sensing system proposed by our group, the combination of a fluorescent catechol-type molecule and boronic acid with electron-rich ligand garners a fresh emissive species at the long-wavelength region. 40 We construct the di-catechol moiety integrated luminogen DiCat with intrinsic functionalization strategy 41 in this work. Involving triethylamine (Et 3 N) as an efficient ligand with DiCat /PBA (phenylboronic acid) solution stimulates the onset of greenish fluorescence under UV excitation.…”

“…We have published a series of research articles based on the luminogens with novel hydroquinone or catechol motif. Innovative sensing mechanism and remarkable detection capability have been achieved towards numerous analytes, including organic boron compound, 40 oxidative species 41 and lithium metal. 42 These species are of great interest in organic synthetic chemistry, analytical chemistry and material chemistry.…”

“…Maximum absorption wavelength is found at 311 nm, which shows a conspicuous bathochromic shift compared with naphthalene. 40 This indicates that effective conjugation might exist between two catechol moieties and the naphthalene core. This inference is verified with theoretical calculations based on the B3LYP functional and 6-31G* basis set.…”

“…Fig.2ashows the ground-state electron structure and conjugation length of DiCat, determined with UV-Vis spectra in THF solution. Maximum absorption wavelength is found at 311 nm, which shows a conspicuous bathochromic shift compared with naphthalene 40. This indicates that effective conjugation might exist between two catechol moieties and the naphthalene core.…”