Calix[4]arene-Based Porous Organic Nanosheets

Abstract

Calixarenes are a common motif in supramolecular chemistry but have rarely been incorporated in structurally well-defined covalent 2D materials. Such a task is challenging, especially without a template, because of the nonplanar configuration and conformational flexibility of the calixarene ring. Here, we report the first-of-a-kind solvothermal synthesis of a calix[4]arene-based 2D polymer (CX4-NS) that is porous, covalent, and isolated as few-layer thick (3.52 nm) nanosheets. Experimental and theoretical characterization of the nanosheets is presented. Atomic force microscopy and transmission electron microscopy results are consistent with the calculated lowest energy state of the polymer. In the lowest energy state, parallel layers are tightly packed, and the calixarenes adopt the 1,2-alternate conformation, which gives rise to a two-dimensional pattern and a rhombic unit cell. We tested the material's ability to adsorb I vapor and observed a maximum capacity of 114 wt %. Molecular simulations extended to model I capture showed excellent agreement with experiments. Furthermore, the material was easily regenerated by mild ethanol washings and could be reused with minimal loss of efficiency.

Synthesis of conjugated polymers via cyclopentannulation reaction: promising materials for iodine adsorption

“…The 200 wt% iodine uptake value of CPP2 is superior to those of polymers reported in the literature, and notable among these are nitrogen-rich triptycene-based materials (NTP, 180 wt%), 59 calix [4]arene-based 2D macromolecules (CX4-NS, 114 wt%), 60 porphyrin and pyrene-based conjugated microporous polymers (Por-Py-CMP, 130 wt%), 61 nitrogen-containing materials (NRPPs, 192 wt%), 57 JLUE covalent organic polymer (JLUE-COP-3, up to 90.29%), 62 conjugated microporous polymers with thiophene units (SCMPs, 222 wt%), 34 hierarchically porous adamantane-based macromolecules (202 wt%), 63 triazine-based covalent frameworks (TTPT, 177wt%), 64 fluorine-enriched polymers (FCMP-600@1-4, up to 141 wt%) 65 and many others. 66,67 The iodine adsorbed by CPP1-3 could be released by simple heating of these latter polymers in air at 125°C.…”

Macrocyclic Arenes‐Based Conjugated Macrocycle Polymers for Highly Selective CO2 Capture and Iodine Adsorption

“…These characterization data clearly suggested that, among the four CMPs, CMP‐4 was the best adsorbent for iodine vapor uptake with a large capacity of 208 wt %. This result is higher than those of many reported materials related to iodine uptake (Supporting Information, Table S6) [12d, 21b, d, 23a, b, 27, 28] …”

“…The iodine vapor capture of CMPs was investigated in ambient air. The experiments were implemented under ambient pressure and at 75 °C, which was based on the typical nuclear fuel reprocessing conditions [27] . In this case, 10 mg of each material was weighed and placed in pre‐weighed glass vessels (2 mL), respectively.…”

“…Thei odine vapor capture of CMPs was investigated in ambient air.T he experiments were implemented under ambient pressure and at 75 8 8C, which was based on the typical nuclear fuel reprocessing conditions. [27] In this case,1 0mgo f each material was weighed and placed in pre-weighed glass vessels (2 mL), respectively.T hereupon, the vessels were loaded in bigger sealed vials (20 mL) containing 500 mg of molecular iodine,f ollowed by being heated in an oven at 75 8 8C. Theiodine capture plots of CMPs made at intervals in 30 hours were shown in Figure 3.…”

Recent progress to construct calixarene-based polymers using covalent bonds: synthesis and applications

“…Moreover, it was easy to regenerate the material through washing with mild ethanol, and therefore it can be recycled with a very small loss of the efficiency. 25 As another study covalent organic polymers 7 and 8 were also examined by Skorjanc et al in terms of pollutant sponges. These polymers were produced using viologens 4, 5 and nitrocalix [4] arene 4 for iodine and toxic dyes capture.…”