We have demonstrated a hydroquinone stitched β-ketoenamine COF acting as an efficient organic cathode in an aqueous rechargeable zinc ion battery.

Covalent organic frameworks (COFs) have attracted surging interest lately due to their wide potential in several frontline application areas like gas storage, sensing, photovoltaics, fuel cells, active catalyst supports, and so on. However, only very few reports are available for the metal-free electrocatalysis over COFs. Herein, we developed a new thiadiazole-based COF, C4-SHz COF, through the reaction between 1,3,5-tris(4-formylphenyl)benzene and 2,5-dihydrazinyl-1,3,4-thiadiazole that possesses a very high specific surface area of 1224 m 2 g −1 , unique molecular architecture, high porosity, and abundant active sites. The as-synthesized C4-SHz COF displayed superior electrocatalytic oxygen evolution reaction (OER) activity and excellent long-term durability. The electrocatalytic performance of the C4-SHz COF achieved a current density of 10 mA/cm 2 at an overpotential of 320 mV. The higher activity of the C4-SHz COF could be attributed to the high Brunauer−Emmett−Teller surface area, porosity, and network structure of the π-conjugated organic building blocks, which allowed fast charge and mass transport processes. This work validates the promising potential of a metal-free COF electrocatalyst toward the OER and its capability to replace carbon-based electrocatalysts.

Covalent organic frameworks (COFs) are promising hosts in heterogeneous catalysis. Herein, we report a dual metalation strategy in a single two-dimensional-COF TpBpy for performing a variety of C–N cross-coupling reactions. [Ir­(ppy)2(CH3CN)2]­PF6 [ppy = 2-phenylpyridine], containing two labile CH3CN groups, and NiCl2 are used as iridium and nickel-metal precursors, respectively, for postsynthetic decoration of the TpBpy COF. Moving from the traditional approach, we focus on the COF-backbone host for visible-light-mediated nickel-catalyzed C–N coupling reactions. The controlled metalation and recyclability without deactivation of both catalytic centers are unique with respect to previously reported coupling strategies. We performed various photoluminescence, electrochemical, kinetic, and Hammett correlation studies to understand the salient features of the catalyst and reaction mechanism. Furthermore, theoretical calculations delineated the feasibility of electron transfer from the Ir center to the Ni center inside the confined pore of the TpBpy COF. The dual metal anchoring within the COF backbone prevented nickel-black formation. The developed protocol enables selective and reproducible coupling of a diverse range of amines (aryl, heteroaryl, and alkyl), carbamides, and sulfonamides with electron-rich, neutral, and poor (hetero) aryl iodides up to 94% isolated yield. The reaction can also be performed on a gram scale. Furthermore, to establish the practical implementation of this approach, we have applied the synthetic strategy for the late-stage diversification of the derivatives of ibuprofen, naproxen, gemfibrozil, helional, and amino acids. The methodology could also be applied to synthesize pharmacophore N,5-diphenyloxazol-2-amine and Food and Drug Administration-approved drugs, including flufenamic acid, flibanserin, and tripelennamine.

Tight-binding approaches bridge the gap between force field methods and Density Functional Theory (DFT). Density Functional Tight Binding (DFTB) has been employed for a wide range of systems containing up...

Hydrogen from water is an alternative energy source that can replace fossil fuels and is environmentally friendly. Various methods have been developed in producing hydrogen from water, including the process of photocatalysis and electrolysis. Photocatalysis is a water splitting event to produce hydrogen from water that utilizes photon energy. Most photocatalyst materials are made of semiconductor material because they have an energy gap that allows them to produce electron-holes if they are subjected to photon energy from a particular source that causes a water splitting event. Water electrolysis is the decomposition of water compounds (H2O) into oxygen gas (O2) and hydrogen gas (H2) by using an electric current through the water. Some of the obstacles of the two methods above are 1) photocatalysis: most of the photocatalyst materials that have been developed to date only work efficiently in the ultra violet light range and the amount of hydrogen production has not been maximized, 2) electrolysis: to produce hydrogen on a large scale, requires electricity in large quantities as a trigger for a reaction, so it requires high production costs. In this paper, through a literature review, a method of separating hydrogen and oxygen from water through a photocatalysis process that utilizes the energy of photons from visible light is combined with the electrolysis process to increase hydrogen production with a fairly small current.