Selective Sugar Recognition by Anthracene-Type Boronic Acid Fluorophore/Cyclodextrin Supramolecular Complex Under Physiological pH Condition

Abstract

We synthesized novel PET (photoinduced electron transfer)-type fluorescence glucose probe 1 [(4-(anthracen-2-yl-carbamoyl)-3-fluorophenyl)boronic acid], which has a phenylboronic acid (PBA) moiety as the recognition site and anthracene as the fluorescent part. Although the PBA derivatives dissociate and bind with sugar in the basic condition, our new fluorescent probe can recognize sugars in the physiological pH by introducing an electron-withdrawing fluorine group into the PBA moiety. As a result, the pKa value of this fluorescent probe was lowered and the probe was able to recognize sugars at the physiological pH of 7.4. The sensor was found to produce two types of fluorescent signals, monomer fluorescence and dimer fluorescence, by forming a supramolecular 2:1 complex of 1 with glucose inside a γ-cyclodextrin (γ-CyD) cavity. Selective ratiometric sensing of glucose by the 1/γ-CyD complex was achieved in water at physiological pH.

A simple supramolecular complex of boronic acid-appended β-cyclodextrin and a fluorescent boronic acid-based probe with excellent selectivity for d-glucose in water

“… 9 These features were identical to those of the 1 : 1 stoichiometric complex of 1 and native β-CyD, suggesting that 1/FPB-βCyD is a supramolecular complex of 1 : 1 stoichiometry. 5 Anthracene compounds form photodimers that are non-emissive upon irradiation; 10 however, the fluorescence spectra of 1/FPB-βCyD showed no change over time with excitation at 323 nm (Fig. S3 † ), suggesting that 1 molecules in solution are not positioned sufficiently close to each other to form photodimers, as these molecules are trapped by excess FPB-βCyD to form 1 : 1 stoichiometric complexes.…”

“…FPB-bCyD, PB-bCyD, and probe 1 were readily synthesised as described previously. [5][6][7] Briey, FPB-bCyD and PB-bCyD were obtained by the amide condensation reaction of 3-amino-bcyclodextrin with the corresponding carboxyphenylboronic acid. Probe 1 was synthesised by the amide condensation reaction of 4-carboxy-3-uorophenylboronic acid pinacol ester with 1-aminopyrene followed by the hydrolysis of the pinacol ester.…”

“…Cyclodextrin (CyD) is water-soluble and has a hydrophobic cavity that can encapsulate the hydrophobic probe; this allows the supramolecular complex to function as a sensor in an aqueous environment. [4][5][6][7] To enhance the affinity of the boronic acid moiety for D-glucose, we introduced an electron-withdrawing uorine group into the phenylboronic acid moiety to increase the Lewis acidity of the boron centre. 5 We also elucidated the sensing mechanism of supramolecular complex 1/FPB-bCyD through comparison with a complex of 1 and phenylboronic acid-appended b-cyclodextrin (PB-bCyD).…”

Supramolecular Zn(II)-Dipicolylamine-Azobenzene-Aminocyclodextrin-ATP Complex: Design and ATP Recognition in Water

“…The most important benefit is that a hydrophobic sensor can work in an aqueous medium. Our group has reported several examples of selective supramolecular sensing systems for sugars [ 10 , 11 , 12 , 13 ].…”

Fluorescence quenching-based bodipy-boronic acid linked viologen dual system for potential glucose sensing applications

“…In these systems, the sensing mechanism has two different structural forms of boronic acid that are used to detect glucose. One of them is boronic acid directly substituted to a fluorophore, such as pyrene (Yu and Yam, 2009), antrecene (Sugita et al, 2019), Bodipy or chiral binaphthols (Liang et al, 2008). In this respect, boronic acid functional group as a saccharide receptor moiety has been directly attached to a Bodipy scaffold to sense the glucose in solution (Zhai et al, 2012;Ndebele et al, 2019).…”