Salicylideneanilines-Based Covalent Organic Frameworks as Chemoselective Molecular Sieves

Abstract

Porous materials such as covalent organic frameworks (COFs) are good candidates for molecular sieves due to the chemical diversity of their building blocks, which allows fine-tuning of their chemical and physical properties by design. Tailored synthesis of inherently functional building blocks can generate framework materials with chemoresponsivity, leading to controllable functionalities such as switchable sorption and separation. Herein, we demonstrate a chemoselective, salicylideneanilines-based COF (SA-COF), which undergoes solvent-triggered tautomeric switching. This is unique compared to solid-state salicylideneanilines' counterpart, which typically requires high energy input such as photo or thermal activation to trigger the enol-keto tautomerisim and cis-trans isomerization. Accompanying the tautomerization, the ionic properties of the COF can be tuned reversibly, thus forming the basis of size-exclusion, selective ionic binding or chemoseparation in SA-COF demonstrated in this work.

Opportunities of Covalent Organic Frameworks for Advanced Applications

“…[68] The resultant COF possesses a relatively high BET surface of 1588 m 2 g −1 with a narrow pore size centered at 1.43 nm. To demonstrate this, Loh and co-workers designed a salicylideneanilines-based COF material (SA-COF) by condensation of 1,3,5-tris(4-aminophenyl) benzene and TFP.…”

Adsorption of Pharmaceutical Pollutants from Water Using Covalent Organic Frameworks

“…[3] Covalent organic frameworks (COFs), [6][7][8][9][10] crystallinep orousm aterials formed by the self-assembly of purely organic building blocks, have been explored for aw ide range of applications, such as optoelectronics, [11][12][13] gas storage, [14] and catalysis. [15][16][17][18][19][20][21][22] COFs have also shown promise as adsorbents for organic dyes, [23][24][25][26][27] mercury, [28,29] radionuclides, [30] and lanthanides, [31] as carriers for drug delivery, [32][33][34] and isolation of industriallyr elevant compounds. [35] Recently, we demonstrated that COFs can be used to efficientlyc apture marine toxin okadaic acid from seawater.…”

Exploration of Thiazolo[5,4‐d]thiazole Linkages in Conjugated Porous Organic Polymers for Chemoselective Molecular Sieving

“…Similarp henomenon hasb een recently reported by Ning et al wherein basic -NH functionality selectively interacts with the -OH groups over -NH 2 to facilitatechemoselective separation in salicylideneanilines-based COFs. [43] We further investigated the chemoselective ability of TzTz-POP-3 in the mixture as it has higher and faster uptake capacity towards -OH containing (FL) dye over -NH 2 based (FU) Dye. To wards this end, TzTz-POP-3 powderw as suspended in aqueous solution of both FL andF U ( % 50 mmol each;1 :1 ratio by vol.)…”