A functional triazine framework based on N-heterocyclic building blocks

Abstract

Covalent organic frameworks constitute a subclass of polymeric materials offering enhanced porosity, functionality and stability. In this work a covalent triazine framework based on bipyridine building blocks is presented, along with a comprehensive elucidation of its local structure, porosity, and capacity for metal uptake. A typical synthesis was carried out under ionothermal conditions at 400 700 C using ZnCl 2 as a Lewis acidic trimerization catalyst. A high degree of local order and the presence of triazine and bipyridine moieties are ascertained at a synthesis temperature of 400 C, along with micropores and specific surface areas of up to 1100 m 2 g 1 . Mesopores are increasingly formed at synthesis temperatures above 450 C, yielding highly porous frameworks with hierarchical porosity and exceptionally large surface areas in excess of 3200 m 2 g 1 at 700 C. We demonstrate the capability of the bipyridine unit to provide specific and strong binding sites for a large variety of transition metal ions, including Co, Ni, Pt and Pd. The degree of metal loading (up to 38 wt%) can be tuned by the metal concentration in solution and is dependent on both the type of metal as well as the temperature at which the CTF was synthesized. Evidence for site specific metal coordination bodes well for the use of metal loaded CTFs as heterogeneous catalysts carrying homogeneous type active sites.

Lithium Charge Storage Mechanisms of Cross-Linked Triazine Networks and Their Porous Carbon Derivatives

“…Two types of triazine--based materials bridged by rigid linkers, para--phenylene (CTF1) 19 and bipyridyl (bipy--CTF), 20 prepared at various temperatures were evaluated as electrodes in order to correlate the electrochemical performance to the surface area and structure (Table 1). Triazine--containing materials with rigid linkers are known to create porous organic networks with high sur--face areas 22 which would allow for increased electrolyte access to the material and greater charge storage capabili--ties.…”

“…The covalent triazine frameworks (CTF) were prepared in a ZnCl 2 melt at tem--peratures between 400°C and 600°C using either para--dicyanobenzene 19 (CTF1 networks) or 5,5'--dicyano--2,2'--bipyridine 20 (bipy--CTF networks) precursors. In a typical synthesis a Duran ampoule (1.5 x 12 cm) was charged with the dinitrile (500 mg) and ZnCl 2 (1--10 equivalents, see Ta--ble 1) in a glove box.…”

“…18 Here, we study similar ma--terials with an emphasis on evaluating the cell perfor--mance of CTFs with different linkers, namely phenylene (CTF1) and 2,2'--bipyridyl (bipy--CTF), see Figure 1 for ideal--ized structures, and prepared at various temperature. These materials are prepared from a para--dicyanobenzene 19 or 5,5'--dicyano--2,2'--bipyridine 20 precur--sors ionothermally in a ZnCl 2 melt, as described previous--ly, with various equivalents of ZnCl 2 and at various tem--peratures.…”

Microporous Organic Polymers for Carbon Dioxide Capture

“…Such high selectivity for CO 2 over N 2 can be explained by Lewis acidbase interactions between the electron-poor CO 2 and the electron-rich sorbent. Another type of COFs is the covalent triazine frameworks (CTFs) [13,[92][93][94][95][96], which were developed by Thomas and co-workers via the cyclical trimerization of cyano reaction groups under ionothermal conditions (Fig. 5.12a).…”

A uniformly porous 2D CN (1 : 1) network predicted by first-principles calculations

“…9,11 Amazingly, these nitrogen-rich carbon materials not only have superior mechanical properties, e.g. 24 However, a pure CN 2D material with a higher nitrogen content than C 3 N, formally formed by trimerization of s-triazine molecules, is missing from reports neither of experimental nor theoretical nature. 15 More interestingly, analogous to graphitic C 3 N 4 , a series of porous sp 2 -bonded structures with higher carbon (and with hydrogen) contents than C 3 N have been synthesized by selfassembling triazine derivatives into covalent frameworks (Fig.…”