Highly Luminescent Metal–Organic Frameworks Based on an Aggregation-Induced Emission Ligand as Chemical Sensors for Nitroaromatic Compounds

Abstract

Three new luminescent metal–organic frameworks (LMOFs) based on d10 metals (Zn2+, Cd2+) and the highly emissive aggregation-induced emission ligand 1,1,2,2-tetrakis­(4-(4-carboxyphenyl)­phenyl)­ethene­(H4tcbpe) are reported, with the formulas [Cd3(tcbpe)1.5­(DMF)­(H2O)2]­·(DMF)6­·(C2H5OH)3 (1), [Zn­(tcbpe)­(DMF)]­·(MeCN) (2), and [Cd­(tcbpe)]­·(MeCN) (3). Compounds 1 and 2 both emit strong green light with internal quantum yields (IQYs) as high as 66.8% and 65.7%, respectively, while compound 3 emits bluish green light with 37.2% IQY. A solution-phase sensing study shows that 1 has the highest sensitivity to nitroaromatic compounds and demonstrates that it is potentially useful as a luminescence-based chemical sensor. Density functional theory calculations are used to explain the sensing mechanism and relative sensitivity of compound 1 to various nitroaromatic compounds.

Aggregation-Induced Emission Properties in Fully π-Conjugated Polymers, Dendrimers, and Oligomers

“…These interactions block vibrational and rotational motions resulting in an increased fluorescence. In this sense, and together with the interest shown in recent years for new materials such as Metal-Organic Frameworks (MOFs), MOFs based on compound 1 of Zr [ 39 , 44 , 45 ], Zn [ 46 , 47 , 48 ], Cd [ 47 ], Hf [ 44 ], or In [ 46 ] have been described.…”

Integration of fluorescent probes into metal–organic frameworks for improved performances

“…Ratiometric uorescent probes with two emission bands are therewith developed in order to overcome the above issue, which measure the uorescence intensities at two different wavelengths and use the ratio as the characteristic parameter to detect the analytes. [79][80][81] MOFs commonly possess uorescence that can be originated from metal ions, 82 organic ligands 83,84 or guests, 85 which makes them available to regulate the accuracy of uorescent probes. That is to say, the uorescence of MOFs can serve as the second signal of ratiometric mode when uorescent probes and MOFs are integrated together, thus improving the accuracy of uorescent probes.…”

Sensing mechanism elucidation of a chemosensor based on a metal‐organic framework selective to explosive aromatic compounds

“…Interest in the in situ chemical detection of nitroaromatic compounds (NACs) accurately and reliably is mainly associated with security, environment pollution, and human health. This has currently encouraged researchers to focus on the design of new chemical sensors that show selective detection of NACs, such as 2,4,6‐trinitrophenol, [ 1 ] nitrobenzene (NB), [ 2 ] and 2,6‐dinitrotoluene, [ 3 ] among others. [ 4 ] Furthermore, these compounds are extensively used in many industrial processes and some of them are highly toxic or carcinogenic.…”