Triptycene based 1,2,3-triazole linked network polymers (TNPs): small gas storage and selective CO₂ capture

Abstract

Herein, facile synthesis and characterization of four Triazole linked Network Polymers (TNPs) in high yields is described. These nitrogen rich polymers are derived using "Click" reaction between 2,6,14triazido triptycene and various di or triethynyl comonomers. The TNPs are microporous and exhibit high surface area (SA BET up to 1348 m 2 g −1 ). Due to incorporation of 1,2,3-triazole motif (a CO 2 -philic moiety), the TNPs record moderate to high CO 2 uptake (upto 4.45 mmol/g at 273K and 1 bar). The TNPs also show very good CO 2 /N 2 (upto 48) and CO 2 /CH 4 (8 -9) selectivity. While highest storage capacity has been registered by TNP4 (CO 2 4.45 mmol/g at 273K and 1 bar, CH 4 23.8 mg/g, H 2 1.8 wt%), the highest CO 2 /N 2 and CO 2 /CH 4 selectivity was shown by TNP3 which contains additional nitrogen rich building blocks in the form of heteroaromatic pyrazine rings. These results suggest that TNPs are porous materials with potential practical application in gas storage and separation. Introduction:Design and syntheses of porous materials have attracted considerable research attention over the past decade. 1-4 In recent years, research output in this direction has witnessed considerable growth. 5-13 Depending on the pore size, porous materials may be classified as ultra-microporous 14-16 microporous, 12,13 mesoporous 17-19 or macroporous. 20,21 Among these, microporous materials have emerged as potential candidates for applications that include but are not limited to gas storage and separation. Microporous materials, such as zeolites 22,23 and metal-organic frameworks (MOFs), 1-5 contain metal atoms. Alternatively, microporous materials can also be designed in the form of metal-free organic polymers that are highly crosslinked. Acronyms such as COFs, CMPs, CTFs, EOFs, HCPs, MOPs, OCFs, PAFs, PIMs, POFs, POPs, PPFs, PPNs, etc have been coined to describe metal-free porous organic polymers. 6-13 In general, MOFs have limited industrial applications as porous materials because presence of relatively labile coordination bonds that lower their thermal stability. 24 On the other hand, in microporous organic polymers (MOPs), light weight elements (such as H, C, N, and O) are interlinked via relatively stronger covalent bonds. Therefore these metal-free materials have lesser mass densities and higher stabilities (chemical and thermal). In addition, MOPs can be easily tailored with respect to properties such as guest selectivity and pore properties, due to availability of a plethora of multifunctional organic molecules that can serve as monomers towards the syntheses of MOPs.In contemporary research dealing with development of microporous materials, design of MOPs for selective CO 2 capture and sequestration has received special attention. This has stemmed from environmental and energy concerns related to CO 2 , which is a major greenhouse gas. It is well known that thermal power plants emitting flue gas (containing approximately 15 % CO 2 ) are a major contributor to anthropogenic CO 2 . Therefore, in order to contain g...

Carbon dioxide capture in amorphous porous organic polymers

“…Nitrogen-rich Triazole-based POPs have also been prepared by "click reactions". 41,[102][103][104] In 2011, Cooper and co-workers reported several types of POPs (A-G) and analyzed their storage capacity for CO 2 . 41 Among these POPs, the network C based on "click reactions" shows the most promising CO 2 uptake of 2.20 mmol g -1 at 298 K and 1 bar due to the electronrich triazole unit in the network.…”

Triptycene‐based fluorescent polymers with pendant alkyl chains: interaction with fullerenes and morphology of thin films

“…molecular sensors (for explosives derived from nitroaromatics) and molecular machinery . Moreover, polymers with iptycenes in main/side chain are reported to be efficient materials for selective capture/storage of gases and adsorbents of dyes for purification of industrial effulents …”

“…[17][18][19][20][21][22] Consequently, such polymers (derived from iptycene monomers) have found application in the design of gas separation membranes, 23,24 organic photovoltaic devices, 25,26 liquid crystals, 27-29 . molecular sensors (for explosives derived from nitroaromatics) 30,31 and molecular machinery. [32][33][34][35] Moreover, polymers with iptycenes in main/side chain are reported to be efficient materials for selective capture/storage of gases [36][37][38][39][40] and adsorbents of dyes for purification of industrial effulents. [41][42][43] These interesting applications of iptycene-derived materials are attributed to the rigid three-dimensional shape of triptycene which resembles a paddlewheel.…”

Design and synthesis of triptycene based fluorescent polymer with pendent triazole: Effect of functionality on host–guest interaction

“…5,[14][15][16] In the past 5 years, design and development of triptycene based polymers have gained a momentum due to several favorable properties of triptycene containing polymers. [17][18][19][20][21][22][23][24][25][26][27] Triptycene derivatives bearing three aromatic rings fused in a bicyclic ring, have become attractive monomers in polymer synthesis because of their unique rigid three-dimensional (3D) molecular geometry. Literature reports suggested that triptycene based polymers exhibit high thermal stability, high glass transition temperature, augmented mechanical properties (ductility, tensile strength, stiffness, high modulus, and toughness), improved organosolubility, low dielectric constant, and others.…”