Fructosyl L-valine (FV) and fructosyl L-glycil L-histidine (FGH) are chemical models used in investigations for the fructosylated hemoglobin (HbA1c) detection and understanding of its reactivity. The recognition and sensing of these fructosylated amino acids by synthetic receptors remains a challenging task. Herein, a new fluorescent Zn(II)-terpyridine-based complex 1 is described and studied in-depth as multifunctional chemosensors for FV, FGH, L-histidine and D-fructose in aqueous-phase at physiological pH. Zn-terpyridine-based chemosensor 1 contains a cationic N-quinolinium nucleus as the optical indicator covalently linked to a strongly acidified phenylboronic acid as a diols binding site. In neutral aqueous media, complex 1 was shown to exhibit a strong affinity towards FGH with a binding constant of log K 4.75 and good selectivity over interfering species such as amino acids and D-glucose. The complex 1 was an order the magnitude more selective for FGH than L-histidine. Complex 1 responds to histidine derivatives via a green turn-on luminescent signal (490 nm) in the micromolar concentrations. In contrast, complex 1 responds to analytes lacking histidine residue with a quenching signal and low affinity. On the basis spectroscopic tools (1H, 11B NMR, UV-Vis and fluorescence titrations), MS-ESI experiments, and DFT calculations, the binding mode between Zn(II)-complex 1 and FGH is proposed in a 1:1 model through cooperative two-point recognition involving the simultaneous coordination of imidazole residue with the zinc(II) atom and reversible esterification of the boronic acid moiety with fructosyl fragment. FGH can be selectively detected using naked-eye detection system based on the Zn-complex 1 and alizarin red S via indicator displacement assay.

Fluorescent recognition and visual detection of fructosyl-amino acids based on a Zn(II)-terpyridine complex with alizarin red S in water

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.