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Owing to their chemical and thermal stabilities, high uptake capacities, and easy recyclability, covalent organic polymers (COPs) have shown promise as pollutant sponges. Herein, we describe the use of diazo coupling to synthesize two cationic COPs, COP1

Calix[4]arene 2 can be directly prepared from p-t-butylcalix[4]arene 1 by concentrated nitric acid or using potassium nitrate and aluminium chloride as a nitrating agent. Product is easily isolated in excellent yield.

Grafting of a carbamoylmethylphosphine oxide (CMPO) calix[4]arene ligand to the silica surface yields an anchored host site that displays an unusual 22.4-fold higher affinity (kDvalue) for EuIIIrelative to AmIII. This sele

Present study describes the adsorption of carbofuran (CF) from aqueous solutions using p-tetranitrocalix[4]arene based modified silica through batch and column methods. Various parameters were optimized including initial pesticide concentrations (5 mg L-1), pH (2-10), contact time (60 min) and adsorbent dosage (30 mg). Modified silica was characterized by FT-IR and scanning electron microscope. The adsorption was further explained by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models. Moreover, adsorption kinetics and adsorption thermodynamics were also investigated. Adsorption in dynamic mode was evaluated by breakthrough volumes and the Thomas model, applying batch conditions using 30 mg of modified silica at pH 5. It has been noticed that CF removal efficiency of modified silica was 98 % as compared to bare silica (48 %). Adsorption of CF on modified silica was found to be multilayer and physical in nature. Consequently, adsorption obeys pseudo-second-order kinetic equation following external mass transfer diffusion process as the rate-limiting step. Thermodynamic parameter (ΔG, ΔS, ΔH) values suggest that the adsorption of CF is spontaneous and exothermic in nature. Thomas model rate constant k TH (cm3 mg-1 min-1) and maximum solid phase concentration (q o mg g-1) was found to be 0.52 and 12.3, respectively, in dynamic mode.

An efficient one step one pot synthesis of p-nitrocalix(n)arenes by ipsonitration of p-tert-butylcalix(n)arenes is described.

Covalently-attached fluorophores may impart enhanced chemosensing capabilities to calixarene frameworks. Synthesis and characterization of six novel dansyl-appended calix[4]arenes, namely, H/Dan4, NO 2/Dan4, H/(OH)2/

New hydroxamic acid derivatives of calixarene have been synthesized by conventional and microwave method. Copyright Taylor & Francis Group, LLC.

Calixarenes 1 were directly nitrated with potassium nitrate and aluminum chloride to give p-nitrocalixarenes 2 in good yields. Formation of p-nitrocalix[4]arene (2a) from reaction of p-bromomethylcalix[4]arene (3) with silver nitrate is also described.

Calixarene-p-sulphonates (tetramer, hexamer, and octamer) have been prepared (75-88percent) and used to give p-nitrocalixarenes (15-22percent yields based on the starting calixarenes).The novel nitration has two advatages: (i) calixarenes are protected from nitric acid oxidation by the electron-withdrawing sulphonate groups and (ii) the difference in the water-solubility of the p-nitrocalixarenes from the sulphonate-containing, lower nitration products, allows ready isolation of the former.The p-nitrocalixarenes thus obtained have potential as intermediates in the synthesis of a variety of functionalised calixarenes.