A Bis(Boronic Ester)-Based Fluorogenic and Chromogenic Sensor for F^-and Cu²⁺

Abstract

In this work, we designed a new boronic ester based ditopic Schiff's base receptor, 2,2′‐(((1E,1′E)‐((2,4,8,10‐tetraoxa‐3,9‐diboraspiro[5.5]undecane‐3,9‐diyl)bis(4,1‐phenylene)) bis(me‐thanylylidene))bis(azanylylidene))diphenol (H2L)by condensing ortho‐aminophenol, 4‐formyl phenyl boronic acid and pentaerythritol. The receptor has been thoroughly characterized by 1H, 13C, 11B NMR spectroscopy as well as high resolution mass spectroscopy and by elemental analyses. Hydrolytic stability of the receptor was also checked by recording its 1H NMR spectrum in mixed DMSO‐d6 and D2O solvent. The receptor acts as highly selective and sensitive probe for the detection of Cu2+ and F– among the studied ions in solution. Both anion and cation sensing studies were thoroughly investigated through multiple optical channels such as UV‐vis absorption and steady state and time‐resolved emission spectroscopic techniques. Among the studied anions, only F– induces color and absorption and emission and time‐resolved emission spectral changes in dimethylsulphoxide.Addition of Cu2+ ion to the solution of the receptor in dimethylsulfoxide‐water (5:2 v/v) leads to remarkable color and absorption spectral changes. Association constants of the receptor towards F– have been also evaluated from the absorption/emission titration data.

Structural, Quantum Chemical and Spectroscopic Investigations on Photophysical Properties of Fluorescent Saccharide Sensor: Theoretical and Experimental Studies

“…Chemically, boron atom itself known to possess three valence electrons with a ground configuration as 1S 2 2S 2 2P 1 and an empty p orbital, which often behaves like a Lewis acid with intend to make bonding with electron‐rich substances and quenches boron's appetite for more electrons. Hence the boronic acid derivatives are more viable to behave as carbohydrate sensors and components in sugar‐permeable membranes ,. which are very prominent and conspicuous in the literature.…”

Recent development of boronic acid-based fluorescent sensors

“…Maity et al reported on new boronic ester sensor 60 that can be used for the detection of both Cu 2+ and F − ions. 121 The addition of F − results in a change in the absorption spectral distribution, which may be ascribed to the coordination of F atoms on the electron-poor boron atoms, resulting in a small blue shift of the lowest energy absorption band, and excessive F − induce the deprotonation of the phenolic O–H protons, resulting in a bright yellow color. The addition of Cu 2+ may result in the charge transfer transition of phenoxide-O to Cu 2+ in the resulting 2 : 1 complex to form a strong and beautiful yellow color.…”

“…Maity et al reported on new boronic ester sensor 60 that can be used for the detection of both Cu 2+ and F À ions. 121 The addition of F À results in a change in the absorption spectral distribution, which may be ascribed to the coordination of F atoms on the electron-poor boron atoms, resulting in a small blue shi of the lowest energy absorption band, and excessive in the resulting 2 : 1 complex to form a strong and beautiful yellow color. This sensor is capable of detecting both Cu 2+ and F À ions as a very rare example.…”

Colorimetric metal ion (II) Sensors Based on imine boronic esters functionalized with pyridine

“…The imine-pyridine [22,64] or imine-phenol [65] moieties have been reported to act as chromophores for a variety of compounds since their photophysical properties can be modify by mean of metal-ligand interaction. Compounds 1a-1c showed an absorption band at 290 nm (Fig.…”