Development of Nitrobenzoxadiazole-Appended Calix[4]arene Conjugate (L) for Selective Sensing of Trivalent Cr³⁺, Fe³⁺, and Al³⁺ Ions in Solution and in the Solid State and Imaging MCF7 cells by {L + Al³⁺}

Abstract

A nitrobenzoxadiazole (NBD)-appended calix[4]arene conjugate (L) possessing a cyclic core formed by connecting the 1,3-positions at the lower rim has been designed. The L has been developed as a receptor for the selective recognition of biologically and ecologically relevant trivalent metal ions, viz., Cr 3+ , Fe 3+ , and Al 3+ . The interaction and region of binding of these metal ions by the receptor L have been explored by isothermal titration calorimetry, spectroscopy, microscopy, and density functional theory (DFT) computational studies. The probe L itself exhibits weak fluorescence emission intensity, and the quantum yield is enhanced by ∼4-fold upon addition of the M 3+ ion due to the chelate enhanced fluorescence effect. Fluorescence enhancement also takes place in L when it interacts with M 3+ even in the solid state and in the MCF7 cancer cells. The binding constant (K b ) for M 3+ by L is ∼10 4 M −1 , supporting that these ions bind to L with moderate strength. The detection limit for all the three metal ions is as low as 4−5 μM. The 1 H NMR data reflects the region of binding of the M 3+ ion to L. The binding is further supported by DFT studies where the space filling structures evidently shows the binding core in L, and the M 3+ ion is buried in this core. As a result of this, the microscopy features are almost the same for L and {L + M 3+ }. The reversible utility of the sensor has been achieved by the addition of H 2 PO 4 − . Based on the input−output information, a molecular logic circuit (INHIBIT logic gate) has been built, which will provide an electronic basis for designing a memory device by the concerned experts.

A Review on Calixarene Fluorescent Chemosensor Agents for Various Analytes

“…Therefore, this chemosensor agent can be reused for the detection and quantification of these trivalent metal ions. Furthermore, a real application of calixarene 3 for the detection of M 3+ ions was also established within MCF-7 cells [38].…”

Coumarin–Calix[4]arene Conjugate-Anchored SiO2 Nanoparticles as an Ultrasensor Material for Fe3+ to Work in Water, in Serum, and in Biological Cells

“…The LOD of Fe 3+ by CouC4A@SiO 2 is (1.75 ± 0.4) pM (SI07, Figure S07c) and is about 5000-fold more sensitive than the calixarene-based probe known in the literature (Table ). − Hence, this is one of the most promising material for sensitive and selective sensing of Fe 3+ .…”

Disposable paper-based PET fluorescence probe linked with calix[4]arene for lithium and phosphate ion detection

“…In fluorescence methodology, fluorescent molecules due to their emissive behavior, easy signal detection, sensitivity, selectivity, and low-cost, offer many advantages over other systems in this area of research. [31][32][33][34][35][36][37][38][39] To date, our team has been working on different types of calix [4]arene-based fluorescence sensors using various fluorophores to detect several molecular ions. [40][41][42][43][44][45] This paper deals with the development of calix [4]arene-based fluorescence sensor (p-C4A).…”

“…In fluorescence methodology, fluorescent molecules due to their emissive behavior, easy signal detection, sensitivity, selectivity, and low-cost, offer many advantages over other systems in this area of research. 31–39…”