A Porous Framework as a Variable Chemosensor: From the Response of a Specific Carcinogenic Alkyl‐Aromatic to Selective Detection of Explosive Nitroaromatics

Abstract

Selective probing of one molecule from one class of similar molecules is highly challenging due to their similar chemical and physical properties. Herein, a novel metal-organic framework FJI-H15 with flexible porous cages has been designed and synthesized, which can specifically recognize ethylbenzene with ultrahigh enhancement efficiency from a series of alkyl-aromatics, in which an unusual size-dependent interaction has been found and proved. It can also selectively detect phenolic-nitroaromatics among a series of nitroaromatics based on energy transfer and electrostatic interactions. Such unusual specificity and variable mechanisms responding to different types of molecules have not yet been reported, which will provide a new strategy for the development of more effective chemosensors based on MOFs for probing small structural differences in molecules.

Devising Chemically Robust and Cationic Ni(II)–MOF with Nitrogen-Rich Micropores for Moisture-Tolerant CO2 Capture: Highly Regenerative and Ultrafast Colorimetric Sensor for TNP and Multiple Oxo–Anions in Water with Theoretical Revelation

“…The S−V plot for TNP shows linearity at a lower concentration range and bends upward with increasing concentration (Figure S15), corroborating the presence of static and dynamic quenching, self-absorption, or an energy transfer process between TNP and 3a. 55,56 A slight red shift of the spectral lines during the incremental addition of TNP to the MOF dispersion also supports this. In contrast, the rest of the nitro analytes show linear S−V plots throughout the whole concentration range (Figure 4c).…”

“…In the quest for exclusive sensing behavior of TNP and to quantitatively evaluate such quenching response, the Stern–Volmer (S–V) equation ( I 0 / I ) = K SV [A] + 1 was applied ( K SV = quenching constant (M –1 ), [A] = molar concentration of analyte, and I 0 and I are luminescent intensities of 3a before and after addition of the NACs, respectively). The S–V plot for TNP shows linearity at a lower concentration range and bends upward with increasing concentration (Figure S15), corroborating the presence of static and dynamic quenching, self-absorption, or an energy transfer process between TNP and 3a . , A slight red shift of the spectral lines during the incremental addition of TNP to the MOF dispersion also supports this. In contrast, the rest of the nitro analytes show linear S–V plots throughout the whole concentration range (Figure c).…”

Introduction of Flexibility into a Metal–Organic Framework to Promote Hg(II) Capture through Adaptive Deformation

“…For example, many MOFs have a relatively high density of Hg­(II) adsorption sites; however, their actual Hg­(II) adsorption capacities are significantly lower than their corresponding theoretical adsorption capacities because of the relatively low utilization ratio of the adsorption sites. ,,,,,, Once the utilization efficiency of the adsorption sites in MOFs can be improved, their Hg­(II) adsorption capacity will be increased. The flexible MOF has the ability to deform adaptively, as induced by a suitable external stimulus. − If both flexibility and Hg­(II) adsorption sites are introduced into a MOF, it is possible to reduce the potential repulsive forces between the adsorbed Hg­(II) ions through deformation of the MOF, thereby improving the utilization efficiency of the adsorption sites and finally increasing the adsorption capacity of the MOF for Hg­(II) ions (Scheme ). To obtain such a desired MOF for Hg­(II) removal, a highly flexible tris­(pyridin-4-ylmethyl)­amine (TPMA) has been selected as the donor (Figure a), and Co­(SCN) 2 , which can provide cheap adsorption sites (SCN – ) for Hg uptake and four additional quadrilateral empty orbitals for pyridine coordination, served as the acceptor (Figure b). ,, Here, a novel MOF ( FJI-H30 ) has been prepared from the TPMA ligands and Co­(SCN) 2 , which has excellent chemical stability and can be used to capture Hg­(II) from an aqueous solution with high adsorption capacity (705 mg g –1 ) and fast adsorption kinetics.…”

A Novel Supramolecular Silver Coordination Complex Based on a Triazole Carboxylate Ligand: Synthesis and Fluorescence Sensing of Colchicine and a Series of Nitro Explosives

“…As a type of chemical primary components, nitro explosives have been used in the field of manufacturing explosives . However, this type of compounds is not only toxic to human and environment but also poses a great threat to homeland security . Thus, it is imperative to detect these nitro compounds.…”