Nitrogen-doped carbon quantum dots conjugated isoreticular metal-organic framework-3 particles based luminescent probe for selective sensing of trinitrotoluene explosive

Abstract

Amine group-containing isoreticular metal-organic framework (IRMOF-3) particles are utilized for the first time as a trinitrotoluene (TNT) sensing material. IRMOF-3 particles are synthesized using zinc nitrate as a metal precursor and 2-amino-1,4benzenedicarboxylic acid as a linker. The nitrogen-doped carbon quantum dots (NCQDs) are synthesized from citric acid and ethylenediamine as carbon and nitrogen precursor, respectively. The NCQDs are conjugated with IRMOF-3 particles as IRMOF-3/NCQDs. The TEM micrograph revealed the average size of IRMOF-3 particles to be 363.66 nm. The photoluminescence emission intensity of IRMOF-3 particles at λ em 430 nm is highly increased in the presence of NCQDs (λ ex 330 nm). Both the assynthesized IRMOF-3 and IRMOF-3/NCQD particles are explored for TNT detection to compare the effect of NCQDs on the IRMOF-3 particle surface. Lower limit of detection (7.5 × 10 −8 M) and higher Stern-Volmer constant (4.46 × 10 6 M −1 ) are achieved by IRMOF-3/NCQD particles. The association constant also increased from 5.3 × 10 4 to 2.78 × 10 6 M −1 after the conjugation of IRMOF-3 particles with NCQDs. Moreover, enhanced selectivity for TNT over trinitrophenol is achieved using the IRMOF-3/NCQD particles.

Carbon Dots: Classically Defined versus Organic Hybrids on Shared Properties, Divergences, and Myths

“…[53] their quenching of fluorescence intensities (namely, relative fluorescence quantum yields). [73][74][75][76][77][78][79][80][81][82] The major attraction of the sensing based on the quenching of fluorescence intensities, coupled with the almost exclusive use of dot samples from thermal carbonization of organic precursors and those of insufficient carbonization in particular, is the commonly obtained large or extremely large apparent Stern-Volmer quenching constants (K SV ), which are translated to high or extremely high sensitivities for trace analyses. [74][75][76][77][78][79][80][81][82] As shown in Table 1, for example, these apparent K SV values (the slopes in plots of experimental quenching data) in aqueous media are orders of magnitude larger than what should be expected in the diffusion controlled limit of quenching for the fluorescence emissions of lifetimes (τ F ) in sub-10 nanoseconds, thus the largest quenching rate constant possible in aqueous solution k q = k d ≤ 10 10 m− 1 s −1 and therefore K SV = k q τ F ≤ 100 m −1 .…”

“…[73][74][75][76][77][78][79][80][81][82] The major attraction of the sensing based on the quenching of fluorescence intensities, coupled with the almost exclusive use of dot samples from thermal carbonization of organic precursors and those of insufficient carbonization in particular, is the commonly obtained large or extremely large apparent Stern-Volmer quenching constants (K SV ), which are translated to high or extremely high sensitivities for trace analyses. [74][75][76][77][78][79][80][81][82] As shown in Table 1, for example, these apparent K SV values (the slopes in plots of experimental quenching data) in aqueous media are orders of magnitude larger than what should be expected in the diffusion controlled limit of quenching for the fluorescence emissions of lifetimes (τ F ) in sub-10 nanoseconds, thus the largest quenching rate constant possible in aqueous solution k q = k d ≤ 10 10 m− 1 s −1 and therefore K SV = k q τ F ≤ 100 m −1 . However, the unusually elevated experimental K SV values (Table 1) are apparently associated only with some of the carbonization produced dot samples, not found with classical CDots in the same fluorescence quenching experiments, as made evident by the direct comparison shown in Figure 7 on the fluorescence quenching of the CS330 and CS200 samples and PEI-CDots by Cu 2+ in aqueous solutions.…”

Emerging Synthetic Methods and Applications of MOF‐Based Gels in Supercapacitors, Water Treatment, Catalysis, Adsorption, and Energy Storage

“…[1][2][3] Regular metal centers and a variety of adjustable organic ligands can be used to form DOI: 10.1002/mame.202200469 porous MOF materials with regular crystal structures via hydrothermal/solvothermal synthesis, [4] ultrasonic, [5][6][7] microwave heating, [8][9][10] electrochemical synthesis, [11][12][13] and mechanochemical synthesis methods. [14][15][16] The classification of MOFs is summarized in Table 1 based on different metal ions/clusters and organic ligands, including the isoreticular metalorganic framework (IRMOF), [17,18] zeolitic imidazolate framework (ZIF), [19,20] coordination pillared-layer (CPL), [21,22] materials of Institut Lavoisier (MIL), [23,24] porous coordination network (PCN), [25,26] and University of Oslo (UiO) [27,28] materials. IR-MOF has a very large pore volume that provides excellent hydrogen storage ability, [29] and ZIF crystals have the structure of a molecular sieve, which provides stability in different solvent systems.…”