Fluorescence turn on amine detection in a cationic covalent organic framework

Abstract

Ionic covalent organic frameworks (iCOFs) are new examples of porous materials and have shown great potential for various applications. When functionalized with suitable emission sites, guest uptake via the ionic moieties of iCOFs can cause a significant change in luminescence, making them excellent candidates for chemosensors. In here, we present a luminescence sensor in the form of an ionic covalent organic framework (TGH+•PD) composed of guanidinium and phenanthroline moieties for the detection of ammonia and primary aliphatic amines. TGH+•PD exhibits strong emission enhancement in the presence of selective primary amines due to the suppression of intramolecular charge transfer (ICT) with an ultra-low detection limit of 1.2 × 10‒7 M for ammonia. The presence of ionic moieties makes TGH+•PD highly dispersible in water, while deprotonation of the guanidinium moiety by amines restricts its ICT process and signals their presence by enhanced fluorescence emission. The presence of ordered pore walls introduces size selectivity among analyte molecules, and the iCOF has been successfully used to monitor meat products that release biogenic amine vapors upon decomposition due to improper storage.

One-pot cascade construction of nonsubstituted quinoline-bridged covalent organic frameworks

“…Covalent organic frameworks (COFs) are a unique class of polymer materials that are fabricated by atomically connecting building blocks with one another through covalent bonds. [1][2][3] With a periodic structure, high accessible surface area, well-dened porosity, and designable construction, COFs are burgeoning as a new research frontier in energy storage, 4,5 separation, 6,7 sensing, [8][9][10] and catalysis. [11][12][13][14][15] It is well recognized that the reversibility of the covalent linkages serves as the major driving force for the formation of long-range ordered COFs.…”

Construction of Halogen-Bonded Organic Frameworks (XOFs) as Novel Efficient Iodinating Agents

“…The relatively low specific surface area may be attributed to the counterion filling in the pores. This results in restriction of the entry of non-interacting guest molecules into the pore channels, and therefore low N 2 uptake was observed. − …”

Imine Bond-Based Fluorescent Nanofilms toward High-Performance Detection and Efficient Removal of HCl and NH3

“…To address the problems, various techniques such as chemosensors, − colorimetric sensors, − electrochemical methods, − and sol–gel-based visualization have been used for the monitoring of them. These techniques, however, are hard to be widely used because they may suffer from some of the shortcomings such as a bulky instrument, slow response, low sensitivity, unfavorable reversibility, specially trained personnel, high cost, etc. − Recently, metal–organic frameworks (MOFs), − nanofibrous membranes, , and polymers were used to conduct the detection.…”