02813nas a2200229   4500008004100000022001400041245013100055210006900186260000800255300001600263490000700279520198000286100002302266700002202289700001802311700002202329700001702351700002602368700002802394700003002422856013102452       2022                        eng d  a2050-748800aCovalent organic framework with electrodeposited copper nanoparticles - a desirable catalyst for the Ullmann coupling reaction0 aCovalent organic framework with electrodeposited copper nanopart  cJUL  a15647-156560 v103 a<p>
	A covalent organic framework is a porous covalently-linked polymeric assembly built from molecular lego blocks, the monomers. A COF's high surface area, ordered pores, and intrinsic low density makes it a perfect heterogeneous catalyst component. Dispersing catalytic metal nanoparticles into the porous COF matrix in a `capping-agent-free' manner can aid the maximal utilization of the active sites. To generate single-site catalysts, metals have been anchored to dense supports, or metal ions have been coordinated to the porous organic framework. The latter has superior atom efficiency and a substrate diffusion advantage. Stably nestling neutral metallic clusters into open-framework supports with no specifically strong binding groups requires a different approach. If infused from extremely dilute electrolytes, metal clusters can be nanoconfined into electrically activated COFs. At low-loadings, it can resemble a single-site catalyst with high atom efficiency. Herein, we report the larger scale synthesis of IISERP-COF15 and electrochemical loading of copper nanoparticles into its pores at loadings as low as 3.34 wt%. We employed classical Ullmann reactions to adjudge its activity. Typical turnover numbers for the catalysts reported in the literature are approximately 50-100. A Cu@COF shows high activity with a very low catalyst loading of 0.25 mol% (TON around similar to 300-350 vs. 4 for neat CuCl2 center dot 2H(2)O (homogeneous catalyst) and turnover frequency (similar to 15-17 h(-1))). We recycled it for up to 3 cycles. Furthermore, we report a multi-fold Ullmann reaction producing an unreported hexaaldehyde to demonstrate the latitude of the catalyst. Our work points to the potential of a dilutely loaded metal@COF as a mimic of the single-site catalyst for synthesizing valuable C-O linked molecules. Our findings from computational modeling shed light on the role of the COF as an active nanoporous support for Ullmann C-O coupling.</p>
1 aChandran, Chandana1 aSingh, Himan, Dev1 aLeo, Liya, S.1 aShekhar, Pragalbh1 aRase, Deepak1 aChakraborty, Debanjan1 aVinod, Chathakudath, P.1 aVaidhyanathan, Ramanathan  uhttps://library.ncl.res.in/content/covalent-organic-framework-electrodeposited-copper-nanoparticles-desirable-catalyst-ullmann03138nas a2200253   4500008004100000022001400041245012100055210006900176260000900245300001200254490000600266520224700272100001702519700002702536700002202563700002202585700001802607700002602625700002102651700001902672700003202691700003002723856013102753       2023                        eng d  a2055-675600aHydroxide ion-conducting viologen-bakelite organic frameworks for flexible solid-state zinc-air battery applications0 aHydroxide ionconducting viologenbakelite organic frameworks for   cJAN   a224-2340 v83 a<p>
	Adaptable polymer-based solid-state electrolytes can be a game-changer toward safe, lightweight flexible batteries. We present a robust Bakelite-type organic polymer covalently decked with viologen, triazine, and phenolic moieties. Its flexible structure with cationic viologen centers incorporates counter-balancing free hydroxide ions into the polymeric framework. By design, the aromatic groups and heteroatoms in the framework can be activated under an applied potential to prompt a push-pull drive, setting off the towing of hydroxide ions via weak electrostatic, van der Waals, and hydrogen-bond interactions. The frontier orbitals from a DFT-modeled structure certify this. The hydroxyl-polymer requires minimal KOH wetting to maintain a humid environment for Grotthuss-type transport. The hydroxide ion conductivity reaches a value of 1.4 x 10(-2) S cm(-1) at 80 degrees C and 95% RH, which is retained for over 15 h. We enhanced its practical utility by coating it as a thin solid-state separator-cum-electrolyte on readily available filter paper. The composite exhibits a conductivity of 4.5 x 10(-3) S cm(-1) at 80 degrees C and 95% RH. A zinc-air battery (ZAB) constructed using this polymer-coated paper as electrolyte yields a maximum power density of 115 mW cm(-2) and high specific capacitance of 435 mA h g(-1). The power density recorded for our ZAB is among the best reported for polymer electrolyte-based batteries. Subsequently, the flexible battery fabricated with IISERP-POF11_OH@FilterPaper exhibits an OCV of 1.44 V, and three batteries in series power a demo traffic signal. To underscore the efficiency of hydroxide ion transport through the complex multifunctional backbone of the polymer, we calculated the diffusion coefficient for OH- (Exp: 2.9 x 10(-5) cm(2) s(-1); Comp. 5.2 x 10(-6) cm(2) s(-1)) using electrochemical methods and MD simulations. Climbing-edge NEB calculations reveal a large energy barrier of 2.11 eV for Zn2+ to penetrate the polymer and identify hydroxide ions within the polymer, suggesting no undesirable Zn2+ crossover. Our findings assert the readily accessible C-C-linked cationic polymer's capacity as a solid-state electrolyte for ZABs and any anion-conducting membrane.</p>
1 aRase, Deepak1 aIllathvalappil, Rajith1 aSingh, Himan, Dev1 aShekhar, Pragalbh1 aLeo, Liya, S.1 aChakraborty, Debanjan1 aHaldar, Sattwick1 aShelke, Ankita1 aAjithkumar, Thalasseril, G.1 aVaidhyanathan, Ramanathan  uhttps://library.ncl.res.in/content/hydroxide-ion-conducting-viologen-bakelite-organic-frameworks-flexible-solid-state-zinc-air