Quinoid-Thiophene-Based Covalent Organic Polymers for High Iodine Uptake: When Rational Chemical Design Counterbalances the Low Surface Area and Pore Volume

Abstract

A novel 2D covalent organic polymer (COP), based on conjugated quinoid-oligothiophene (QOT) and tris­(aminophenyl) benzene (TAPB) moieties, is designed and synthesized (TAPB-QOT COP). Some DFT calculations are made to clarify the equilibrium between different QOT isomers and how they could affect the COP formation. Once synthetized, the polymer has been thoroughly characterized by spectroscopic (i.e., Raman, UV–vis), SSNMR and surface (e.g., SEM, BET) techniques, showing a modest surface area (113 m2 g–1) and micropore volume (0.014 cm3 g–1 with an averaged pore size of 5.6–8 Å). Notwithstanding this, TAPB-QOT COP shows a remarkably high iodine (I2) uptake capacity (464 %wt) comparable to or even higher than state-of-the-art porous organic polymers (POPs). These auspicious values are due to the thoughtful design of the polymer with embedded sulfur sites and a conjugated scaffold with the ability to counterbalance the relatively low pore volumes. Indeed, both morphological and Raman data, supported by computational analyses, prove the very high affinity between the S atom in our COP and the I2. As a result, TAPB-QOT COP shows the highest volumetric I2 uptake (i.e., the amount of I2 uptaken per volume unit) up to 331 g cm–3 coupled with a remarkably high reversibility (>80% after five cycles).

Amide-Linked cis,cis-1,3,5-Cyclohexanetricarbonyl-Based Porous Organic Polymers for the Uptake of Iodine in Solution and Vapor Phase

“…Similarly, CD-POP experienced a reduction in iodine adsorption capacity, dropping from 260 to 220 wt % (Figure d). The reduction in iodine uptake by the POPs after five cycles may be linked to the partial irreversible absorption of iodine by the POPs and, conceivably, the trapped iodine within the inner pores of the materials that remain unremoved despite washing with solvents. , The recovered POPs demonstrated similar morphological and chemical characteristics to the as-prepared POPs, as verified by analyzing the SEM images (Figure S17) and the EDAX data (Figure S18).…”

“…Furthermore, the percentage of iodine uptake by PD-POP was estimated to be 306 wt % using TGA (Figure S8). 38 To the best of our knowledge, this is the first report of iodine adsorption by amide-based POPs. In general, the host−guesttype interaction between the polymer and I 2 increases with an increase in the extent of heteroatoms (N, S, O, and F) present in the POPs (Table S3).…”

Impact of Conformational Isomerism in Two Zn-MOFs on the Multimedia Incarceration of Iodine: In-Depth Experimental and Computational Assessments

“…In all the above-mentioned cases, surface as well as inclusion-based iodine transfer is likely to occur even with a less porous nature of the framework . From the results of multiphase iodine transfer studies conducted with 1 and 2 , it can be inferred that the uptake values in this work are better than many MOFs, POPs, and zeolites (Table S1) − ,− For instance, the values of vapor phase iodine mass transfer for a T -SCNU-Z6 and a W -SCNU-Z6 are 2.05 g g –1 and 5.04 g g –1 , respectively, whereas, those for HSB-W8 and Co-IPT-IBA are 2.32 g g –1 , and 2.88 g g –1 , respectively. Compared to this, ionic iodine transfer studies in the aqueous phase are rare.…”

A para-azaquinodimethane integrated quinoidal conjugated microporous polymer

“…However, 2D-quinoidal polymers have been developed so far. Although Yildrim et al recently developed a quinoid-oligothiophene incorporated covalent organic polymer (COP), the polymer was used for iodine uptake, 36 with no discussion about the optoelectronic properties/applications.…”