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-ullmann02092nas a2200277   4500008004100000245013500041210006900176260000800245300001100253490000700264520112600271100002201397700003701419700001701456700002201473700001701495700001801512700001701530700002701547700002501574700002001599700002601619700001801645700003001663856012101693       2023                        eng d00aCOF-supported zirconium oxyhydroxide as a versatile heterogeneous catalyst for Knoevenagel condensation and nerve agent hydrolysis0 aCOFsupported zirconium oxyhydroxide as a versatile heterogeneous  cNOV  a1080880 v263 a<p>
	A composite of catalytic Lewis acidic zirconium oxyhydroxides (8 wt %) and a covalent organic framework (COF) was synthesized. X-ray diffraction and infrared (IR) spectroscopy reveal that COF's structure is pre-served after loading with zirconium oxyhydroxides. Electron microscopy confirms a homogeneous distri-bution of nano-to sub-micron-sized zirconium clusters in the COF. 3D X-ray tomography captures the micron-sized channels connecting the well-dispersed zirconium clusters on the COF. The crystalline ZrOx(OH)(y)@COF's nanostructure was model-optimized via simulated annealing methods. Using 0.8 mol % of the catalyst yielded a turnover number of 100-120 and a turnover frequency of 160-360 h(-1) for Knoevenagel condensation in aqueous medium. Additionally, 2.2 mol % of catalyst catalyzes the hy-drolysis of dimethyl nitrophenyl phosphate, a simulant of nerve agent Soman, with a conversion rate of 37% in 180 min. The hydrolytic detoxification of the live agent Soman is also achieved. Our study unveils COF-stabilized ZrOx(OH)(y) as a new class of zirconium-based Lewis + Bronsted-acid catalysts.</p>
1 aShekhar, Pragalbh1 aDevulapalli, Venkata, Swaroopa D1 aReji, Reshma1 aSingh, Himan, Dev1 aJose, Aleena1 aSingh, Piyush1 aTorris, Arun1 aVinod, Chatakudath, P.1 aIII, John, A. Tokarz1 aMahle, John, J.1 aPeterson, Gregory, W.1 aBorguet, Eric1 aVaidhyanathan, Ramanathan  uhttps://library.ncl.res.in/content/cof-supported-zirconium-oxyhydroxide-versatile-heterogeneous-catalyst-knoevenagel