Covalent triazine frameworks (CTFs) are normally synthesized by ionothermal methods.T he harsh synthetic conditions and associated limited structural diversity do not benefit for further development and practical large-scale synthesis of CTFs.Herein we report anew strategy to construct CTFs (CTF-HUSTs) via apolycondensation approach,which allows the synthesis of CTFs under mild conditions from aw ide arrayo fb uilding blocks.I nterestingly,t hese CTFs displayalayered structure.T he CTFs synthesized were also readily scaled up to gram quantities.T he CTFs are potential candidates for separations,p hotocatalysis and for energy storage applications.I np articular,C TF-HUSTs are found to be promising photocatalysts for sacrificial photocatalytic hydrogen evolution with am aximum rate of 2647 mmol h À1 g À1 under visible light. We also applied ap yro-lyzed form of CTF-HUST-4 as an anode material in asodium-ion battery achieving an excellent discharge capacity of 467 mAh g À1. Covalent organic frameworks (COFs) are an emerging class of porous materials,characterized by their ordered structures, high surface areas,and structural diversity. [1] They have shown promise in applications such as gas adsorption, [2] catalysis, [3] and optoelectronics. [4] Av ariety of methods have been reported to prepare COFs,s uch as polycondensation, [1a, 4a] cyclization reactions, [5] or surface mediated methods. [1b, 6] Covalent triazine frameworks (CTFs) are related to COFs and are typically constructed through cyclization reaction of nitrile aromatic building blocks;t hey feature high physico-chemical stability and high nitrogen content. [5, 7] Because of these characteristics,CTFs have found diverse applications in gas adsorption and storage, [5a, 7a,b] catalysis, [7c-e] and energy storage. [7f,g] There are still, however, al imited number of approaches for the synthesis of CTFs. [5a, 7a] Themost common approach is ionothermal synthesis at high temperatures (! 400 8 8C), which also requires alarge amount of ZnCl 2 to serve as both catalyst and reaction medium. [5a] This method can lead to CTFs with ad egree of crystalline order,b ut the high reaction temperatures cause the partial carbonization of the structure and the materials are obtained in the form of black powders.H ence,C TFs prepared by this method lack an electronic band gap and may be unsuitable for photophysical applications.F urthermore,t hese reaction temperatures consume alarge amount of energy and preclude all but the most stable building blocks,thus limiting the scope for scale up and synthetic diversity.I ti s, therefore,i mperative to find new methods for the synthesis of CTFs under milder conditions. Previous research has shown that CTFs could be synthesized at room temperature,a nd catalyzed by strong and corrosive acid such as trifluoromethylsufonic acid. [7a,b] This avoids carbonization, but the method is obviously not suitable to acid-sensitive building blocks,and also the resulting materials did not have layered structures. Here,wedevelop anew strategy involvi...

Graphitic carbon nitride has been predicted to be structurally analogous to carbon-only graphite, yet with an inherent bandgap. We have grown, for the first time, macroscopically large crystalline thin films of triazine-based, graphitic carbon nitride (TGCN) using an ionothermal, interfacial reaction starting with the abundant monomer dicyandiamide. The films consist of stacked, two-dimensional (2D) crystals between a few and several hundreds of atomic layers in thickness. Scanning force and transmission electron microscopy show long-range, in-plane order, while optical spectroscopy, X-ray photoelectron spectroscopy, and density functional theory calculations corroborate a direct bandgap between 1.6 and 2.0 eV. Thus TGCN is of interest for electronic devices, such as field-effect transistors and light-emitting diodes.

Suitably functionalized dipeptides have been shown to be effective hydrogelators. The design of the hydrogelators and the mechanism by which hydrogelation occurs are both currently not well understood. Here, we have utilized the hydrolysis of glucono-delta-lactone to gluconic acid as a means of adjusting the pH in a naphthalene-alanylvaline solution allowing the specific targeting of the final pH. In addition, this method allows the assembly process to be characterized. We show that assembly begins as charge is removed from the C-terminus of the dipeptide. The removal of charge allows lateral assembly of the molecules leading to pi-pi stacking (shown by CD) and beta-sheet formation (as shown by IR and X-ray fiber diffraction). This leads to the formation of fibrous structures. Electron microscopy reveals that thin fibers form initially, with low persistence length. Lateral association then occurs to give bundles of fibers with higher persistence length. This results in the initially weak hydrogel becoming stronger with time. The final mechanical properties of the hydrogels are very similar irrespective of the amount of GdL added; rather, the time taken to achieving the final gel is determined by the GdL concentration. However, differences are observed between the networks under strain, implying that the kinetics of assembly do impart different final materials' properties. Overall, this study provides detailed understanding of the assembly process that leads to hydrogelation.

A range of conjugated microporous polymer networks has been prepared using Sonogashira-Hagihara cross-coupling of 1,3,5-triethynylbenzene with a number of functionalized dibromobenzenes. Porous poly(arylene ethynylene) networks with surface areas up to 900 m2/g were produced. The surface chemistry of the networks was varied by monomer selection, thus allowing control over physical properties such as hydrophobicity. Additionally, it was shown that the dye sorption behavior of the networks can be controlled by varying the hydrophobicity. This expands significantly on the utility of this approach, allowing high surface area networks to be prepared with properties that can be tailored for applications such as catalysis and separations

Microporous materials have potential applications in areas including molecular separation, gas sorption and catalysis. [1] Materials such as metal-organic frameworks (MOFs), [2] covalent organic frameworks (COFs), [3] microporous organic polymers, [4] and porous organic molecular solids [5] all contain organic functionalities which, in principle, can allow significant synthetic diversification. A particular advantage of microporous organic polymers [4] is the potential to introduce a range of useful chemical functionalities into the pores. [6] This stems from the chemical and thermal stability of these networks which facilitates a variety of chemical transformations.Conjugated microporous polymers (CMPs) [4a] can exhibit extended p-conjugation and have been the subject of much recent interest. A variety of CMPs (and closely related structures) have been developed. [4a, 7] The incorporation of metal sites into CMPs could open up second-generation porous materials with useful combined chemical and physical properties such as catalytic activity, electrical conductivity, or light-absorption/emission.[8] For example, metalated CMP materials might be of interest in heterogeneous catalysis or photocatalysis, where high surface areas would be beneficial. There are, however, few demonstrations of the functionalization of CMP networks with metals at the molecular level. The incorporation of metal nanoparticles into microporous networks has been demonstrated.[4e, 7e, 9a] Also, a lithiated CMP showing very high H 2 sorption was described recently but the precise nature of the metal incorporation at the molecular level was not clear.[9b] Another recent report details a porphyrin-derived microporous organic polymer which shows high catalytic activity for the oxidation of thiols. [10] Beyond this, there are no reports on the purposeful synthesis of metal-functionalized CMPs. Here, we report two versatile strategies for preparing metal-organic CMPs (MO-CMPs). Unlike MOFs, [2] the resulting metal-containing conjugated polymers are amorphous. Another significant difference is that the metal sites need not be nodes in the network but can also be attached pendant to the polymer chains, thus allowing the introduction of vacant metal sites and a range of chemically active functionalities. The introduction of pendant metal sites rather than metal nodes also allows the preparation of materials with unbroken extended conjugation.The MO-CMP networks were prepared either by posttreating a bipyridine-functionalized CMP precursor with a metal complex or by the direct Sonogashira-Hagihara crosscoupling of 1,3,5-triethylbenzene or 1,4-dibromobenzene and a halogenated metal-organic co-monomer. These two strategies can be defined as post-synthetic metalation and direct metal incorporation by copolymerization. The representative structures of the target MO-CMP networks are shown in Scheme 1. These polymers combine conjugation along the main chain with functional units such as bipyridine or phenylpyridine in the backbone in order to provide site...

The choice of reaction solvent has a major influence on the surface area and pore volume in conjugated microporous polymer (CMP) networks synthesized by Sonogashira-Hagihara palladium-catalyzed cross-coupling chemistry of aromatic dibromo monomers with 1,3,5-triethynylbenzene. Four solvents were evaluated for these reactions: N,N-dimethylformamide (DMF), 1,4-dioxane, tetrahydrofuran (THF), and toluene. Networks synthesized in DMF tend to exhibit the highest surface areas (up to 1260 m2/g), whereas those synthesized in toluene have on average significantly lower surface areas and pore volumes. By judicious choice of reaction solvent, microporous materials can be prepared which combine high surface area with a variety of functional groups of interest in applications such as gas storage, molecular separations, and catalysis

Conjugated microporous polymers (CMPs) based on the electron-withdrawing 1,3,5-triazine node (TCMPs) were synthesized by palladium-catalyzed Sonogashira-Hagihara cross-coupling. The porosity in these polymers was found to be comparable to the analogous 1,3,5-connected benzene CMP systems that we reported previously, demonstrating that nodes can be substituted in these amorphous materials in a rational manner, much as for certain crystalline porous metal-organic frameworks. The CO 2 adsorption properties of the TCMPs were measured and compared with the corresponding CMPs, and it was found that the TCMP networks adsorbed more CO 2 than CMP analogues with comparable BET surface areas. Network TNCMP-2 showed the highest surface area (995 m 2 g À1 ) and a CO 2 uptake of 1.45 mmol g À1 at 1 bar at 298 K. The band gap in these triazine-based CMPs could also be engineered through copolymerization with other functional monomers.

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