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

Abstract

A new fluorescent 1,3-diaminonaphthalimide conjugate of calix[4]arene receptor (R) was synthesized and characterized. The receptor displays good selectivity towards trinitrophenol (TNP) over other explosive aromatic- and aliphatic-nitro compounds by exhibiting changes in its fluorescence emission. Receptor-coated cellulose paper strips are equally effective in terms of their selective detection of TNP over other aromatic- and aliphatic-nitro compounds. When used in solution or on cellulose paper strips, R can detect up to submicromolar concentration of TNP by exhibiting changes in its fluorescence emission and in its supramolecular structure upon interaction. Interestingly, the microscopy features of R, TNP, and {R+TNP} are quite distinct, indicating the interactions present between R and TNP, as studied by using AFM and TEM. Computationally modeled complexes of receptor with TNP and TNT show enormous difference in their interaction energies in the favor of TNP by showing the host-guest interaction of cation⋅⋅⋅anion type in the presence of TNP but not TNT. This is because the receptor adopts an "arms-open"-type structure in the case of the TNP complex, whereas it adopts an "arms-closed"-type structure in the presence of TNT. Both the experimental and the computational studies reveal that the receptor selectively binds to TNP over TNT. Thus, R-coated Whatman No.1 filter paper strips provide easy, rapid, and economical detection of trace amounts of TNP both by visual and spectral measurement.

1,3-Di-naphthalimide Conjugate of Calix[4]arene as a Sensitive and Selective Sensor for Trinitrophenol and This Turns Reversible when Hybridized with Carrageenan as Beads

“…A lower rim di-derivative of naphthalimide-conjugated p-tert- butylcalix[4]arene ( L 1 ) was synthesized, characterized, and demonstrated for selective recognition of trinitrophenol using absorption and fluorescence spectroscopy. Upon replacing the −NH 2 that is reported in our previous paper 35 by −NHCH 2 CH 2 NH 2 moiety, the sensing becomes more prominent by shifting the LOD from 300 to 29 nM, which is the lowest among a number of other calixarene conjugates reported in the literature for TNP sensing ( Table 2 ). 34 − 39 By introducing the L 1 into the carrageenan beads, this sensor system turns reversible unlike the earlier reports given in Table 2 .…”

Elucidating sensing mechanisms of a pyrene excimer-based calix[4]arene for ratiometric detection of Hg(ii) and Ag(i) and chemosensor behaviour as INHIBITION or IMPLICATION logic gates

“…Many quantum-chemical-based studies have focused their attention on the formation of isolated pyrene-excimer 46 and their properties as well as in the investigation on the binding of different analytes using calix [4]arene scaffolds. 47,48 More recently, density functional theory (DFT) has been employed to understand the sensing mechanism of lysine through the formation of the intermolecular pyrene-excimer. 49 Herein we present the synthesis and characterisation of two calix [4]arene derivatives composed by pyrene units connected through a thiourea-based spacer.…”

Supramolecular Sensing of 2,4,6-Trinitrophenol by a Tetrapyrenyl Conjugate of Calix[4]arene: Applicability in Solution, in Solid State, and on the Strips of Cellulose and Silica Gel and the Image Processing by a Cellular Phone

“…17−25 Although there are reports for the selective recognition of TNP, supramolecular systems such as calixarene-based ones are limited and all of these receptors detect TNP by fluorescence quenching. 26−29 Calixarenes can be easily functionalized on its upper or lower rim to meet the requisite needed in providing complementary interacting sites with the guest molecules.…”