Calixarenes are considered as third generation supramolecules with hollow cavity-like architecture whereas nanoparticles are small entities with dimensions in the nanoscale. Many exciting achievements are seen when the calix system merges with nanoparticles which produces many fascinating facets in all fields of contemporary chemistry. The properties of nanoparticles which are tuned by calixarenes find applications in sensing, catalysis, molecular recognition, etc. Here, we have reviewed the chemistry of calix-based nanoparticles, and emphasis is laid on the modified, reducing, templated and stabilizing roles of calixarenes. This review covers the research being carried out in the domain of calix protected metal nanoparticles during last 18 years under the canopy of important 109 references. This article contains 58 figures which include 81 easy to understand structures. Calix-protected nanoparticles have enthralled researchers in the field of nanoscience with a tremendous growth in its applications, which heralds much promise to become in future a separate area of research.

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A novel fluorescent thiacalix[4]arene-tetra-(quinoline-8-sulfonate) (TCTQ8S) was synthesized by condensation of thiacalix[4]arene (TCA) and 8-quinoline sulfonyl chloride(8QSC). TCTQ8S was characterized by ESI-MS, (1)H-NMR and (13)C-NMR spectroscopic methods. TCTQ8S was found to be an efficient "turn-off" fluorescent sensor for the selective and sensitive recognition of Co(II) ions. The Job's plot measurement reveals a 1:1 stoichiometric ratio. The designed chemosensor exhibited high selectivity toward Co(II) ions vs. other tested metal ions, with a detection limit of up to 1.038 × 10(-9) M. The binding constant and quantum yield for the complex were also determined. Molecular docking studies have been successfully performed to support 1:1 binding of TCTQ8S with the Co(II) metal ion. TCTQ8S was evaluated for real sample analysis on water sample for the detection of Co(II). Graphical Abstract Thiacalix derivatized fluorescent sensor for the selective detection of Co(II).

A newly synthesized thiacalix[4]arene dinaphthalene sulfonate, i.e., TCDNS, has been used as a fluorescence quencher for 2,3-DNT as well as 4-NT. The complex was analyzed by ESI-MS and 1H-NMR titration, which has been further confirmed by the in silico study.