Novel One-Dimensional Covalent Organic Framework as a H⁺ Fluorescent Sensor in Acidic Aqueous Solution

Abstract

Covalent organic frameworks (COFs) represent an emerging class of two- or three-dimensional crystalline porous materials with delicate control over topology, composition, and porosity. Here, we develop a new COF made up of 1,3,6,8-tetrakis­(p-formylphenyl)­pyrene (TFPPy) and 4,4′-diaminobenzophenone (DABP) that exhibits a rare one-dimensional (1D) structure. The resulting frameworks possess good crystallinity, comparatively high Brunauer–Emmett–Teller (BET) surface area (426 m2/g), and good thermal stability (360 °C). Impressively, this 1D COF shows strong fluorescence and can be used as an excellent H+ sensor in an acidic aqueous solution.

Enhanced surface area and reduced pore collapse of methylated, imine-linked covalent organic frameworks

“…8 Several studies report on COF-based chemosensors for the detection of gaseous hydrochloric acid, 25,26 and a series of aqueous Brønsted acids. 26,27 Recently, Yang et al have studied the effect of imine-protonation on the optical properties of three imine-linked COFs. It was found that all COFs showed a bathochromic shift after acid exposure due to the protonation of the imine bond.…”

Modulation of stimuli‐responsiveness toward acid vapor between real‐time and write‐erase responses based on conjugated polymers containing azobenzene and Schiff base moieties

“…We herein report the design and syntheses for azasubstituted conjugated polymers possessing environment responsiveness. Based on the azobenzene 32,33,[35][36][37][38][39][40] and Schiff base [41][42][43][44][45][46] structures, we prepared copolymers with fluorene and bithiophene units. We successfully obtained three types of polymer films and evaluated stimuli responsivity.…”

Porous organic polymers as a platform for sensing applications

“…27e), through the condensation of 1,3,6,8-Tetrakis(p-formylphenyl) pyrene (TFPPy) and 4,4 0 -diaminobenzophenone (DABP). 215 COF-TP displays pH-dependent fluorescence emission in acidic solution in the pH range of 0-6. The PL intensity shows a linear decrease with the decrease of the pH value, and is almost quenched at pH =0, accompanied by an obvious color change from orange (pH = 6) to black (pH = 0) under both sun and UV light (365 nm) (Fig.…”