Novel calix[4]pyrrole assembly: Punctilious recognition of F − and Cu +2 ions

Benzene Sulfonyl Linked Tetrasubstituted Thiacalix[4]arene for Selective and Sensitive Fluorometric Sensing of Sulfosulfuron along with Theoretical Studies

Herein, we designed two fluorescent tetrasubstituted benzene sulfonyl appended Thiacalix[4]arene receptors named L1 and L2, which sensitively and selectively detect Sulfosulfuron among other herbicides and pesticides. The detection limit (LOD) was found to be 0.21 ppm and 0.35 ppm, and the enhancement constant (Ks) was determined to be 7.07 X 104 M-1 and 5.55 X 104 M-1 for L1 and L2, respectively. Using the non-linear regression method, the association constant was obtained as 2.1 X 104 M-1 and 2.23 X 104 M-1 whereas, the binding ratio was found to be 1:1 for both L1 and L2, respectively. Additionally, the interference studies show the selective nature of receptors for Sulfosulfuron among its sulfonylurea family. To further confirm the interaction mechanism, 1H-NMR spectroscopy, and a computational investigation were carried out, which validates the 1:1 binding ratio. The receptors were found to be recyclable in nature with simple acid-base treatment. This new approach of using supramolecules as fluorescent probes for sensitive and selective detection of herbicides is rare in the literature.

A versatile enrichment of functionalized calixarene as a facile sensor for amino acids

Amino acids have become the most important part of the human biological system due to their roles in the living processes. Role of amino acids stretches beyond their traditional role as a building block for proteins, deficiency of the same could lead to decreased immunity, digestive problems, depression, fertility issues, lower mental alertness, slowed growth in children, and many other health issues. The acute detection of amino acids is necessary to determine the human health domain. Here in this review, we summarize and study the calixarenes as a complex detailed being of an immeasurable value and its utilization for the amino acids' detection. The key factors responsible such as noncovalent forces, LOD and supramolecular chemistry of calixarenes with amino acids are described well. This study presents the most recent efforts made for the development of potential and highly efficient calixarene based sensors for the detection of amino acids.

Recent Advancements for the Recognization of Nitroaromatic Explosives Using Calixarene Based Fluorescent Probes

In this era, explosives are easily available compared to the early days. Thus, more effective detection of explosives has become the main concern of homeland security. In the past decades, a large number of sensing materials have been developed for the detection of explosives in solid, vapor, and solution states through fluorescence methods. In recent years, great efforts have been devoted to developing new fluorescent materials with various sensing mechanisms for detecting explosives in order to achieve super-sensitivity, ultra-selectivity, as well as fast response time. Modified calixarenes have high potentials to detect nitroaromatic compounds (NACs) due to their favorable structural properties. It summarizes the detection of NACs by the modified calixarene system formed by the complex. Various methodologies responsible for complex formation and binding mechanisms (PET, FRET, EE, etc.) are the centerpiece of this review. Finally, conclusions and future outlook are presented and discussed.