Fluorescence and Piezoresistive Cantilever Sensing of Trinitrotoluene by an Upper-Rim Tetrabenzimidazole Conjugate of Calix[4]arene and Delineation of the Features of the Complex by Molecular Dynamics

Abstract

A new benzimidazole-functionalized calix[4]arene receptor (R) was synthesized and characterized. The receptor R shows better selectivity toward trinitrotoluene (TNT) compared to the other nitro explosives in solution, which also retains its effectiveness for solid-phase detection. The chemical interactions of the molecule with different nitro explosive analytes were studied by fluorescence spectroscopy and by a molecular dynamics approach. The molecular dynamics studies show a 1:3 complex between R and TNT, and hence high sensitivity was imparted by fluorescence studies. The detection of explosive vapors in ambient conditions was tested by using a sensitive coating layer of R on an SU-8/CB-based piezoresistive cantilever surface. The developed device showed large sensitivity toward TNT compared to cyclotrimethylenetrinitramine (RDX) and pentaerythritol tetranitrate (PETN) in the solid state at their respective vapor pressures at room temperature. The detection sensitivity of the device was estimated to be 35 mV for TNT at ambient conditions. Moreover, the sensor does not show a response when exposed to humidity. These results demonstrate that R can be used as one of the coating materials for a cantilever for the detection of TNT using piezoresistivity measurement. R can also detect the explosives in solution with high sensitivity and selectivity by fluorescence spectroscopy.

A Fluorescent 1,3‐Diaminonaphthalimide Conjugate of Calix[4]arene for Sensitive and Selective Detection of Trinitrophenol: Spectroscopy, Microscopy, and Computational Studies, and Its Applicability using Cellulose Strips

“…Calixarenes can be easily modified on its upper‐ or lower‐rim to meet the requisite needs in providing complementary interacting sites with the analyte 44–51. In addition, the arene cavity of calix platform is also utilized for trapping the guests as reported by us as well as others 52. 53 In this regard, a highly fluorescent amine‐functionalized di‐derivative of calix[4]arene ( R ) has been synthesized and characterized, and its ability to selectively recognize TNP over TNT is studied using spectroscopy and microscopy.…”

“…[44][45][46][47][48][49][50][51] In addition, the arene cavity of calix platformi sa lso utilized for trapping the guests as reportedb yu sa sw ella so thers. [52,53] In this regard, ah ighly fluorescent amine-functionalized di-derivative of calix [4]arene (R) has been synthesized and characterized, and its ability to selectively recognize TNP over TNT is studied using spectroscopy and microscopy.T he specieso fr ecognition were addressed through DFT computations. In the process, an easy and cost-effectiver eal-timem onitoring of the TNP using R coated filter papers trips has been demonstrated.…”

Luminescence Based Detection of Trinitrophenol and Aromatic Organophosphorous Pesticides Using a Coordination Polymer

“…Current methods to detect explosives include trained canines or sophisticated instruments, [23] such as ion mobility spectrometry, [24] energy dispersive X-ray diffraction, [25] plasma desorption mass spectrometry, [26] surface-enhanced Raman spectroscopy [27][28][29] and different imaging technologies. [30] For pesticide detection commonly used techniques are gas chromatography, [31][32] high performance liquid chromatography [33][34] and mass spectrometry.…”

A 1,3‐Capped Calix[4] Conjugate Possessing an Amine Moiety as an Anion Receptor: Reversible Anion Sensing Detected by Spectroscopy and Characterization of the Supramolecular Features by Microscopy

“…Among these systems, calixarenes were preferential owing to the ease of functionalization on both the upper and lower rims, and the presence of apreorganized core, which is required to improvei on selectivity. [23][24][25][26] Calix[n]arenes possessing urea/thiourea [27] and amide [28,29] moieties were developed as anion sensors in which the interactions werem ainly manifested by hydrogen bondinga nd were electrostatic when aq uaternized ammonium center [30] was present.I na ddition, the metal-ion complexes of calix conjugates have been developed as anion sensors. [31,32] However, calix [4]arene conjugates that possessareduced imine moiety (ÀH 2 CÀNHÀ)a nd exhibit selective recognition for phosphates and such systems are rather scarce in the literature.…”