02312nas a2200241 4500008004100000022001400041245012600055210006900181260000800250520143000258653001601688653003201704653002201736653002301758653002501781100002601806700002201832700002201854700002001876700001801896700003001914856012601944 2019 eng d a1861-472800aAg nanoparticles supported on a resorcinol-phenylenediamine-based covalent organic framework for chemical fixation of CO20 aAg nanoparticles supported on a resorcinolphenylenediaminebased  cOCT3 a

Covalent organic frameworks are a new class of crystalline organic polymers possessing a high surface area and ordered pores. Judicious selection of building blocks leads to strategic heteroatom inclusion into the COF structure. Owing to their high surface area, exceptional stability and molecular tunability, COFs are adopted for various potential applications. The heteroatoms lining in the pores of COF favor synergistic host-guest interaction to enhance a targeted property. In this report, we have synthesized a resorcinol-phenylenediamine-based COF which selectively adsorbs CO2 into its micropores (12 angstrom). The heat of adsorption value (32 kJ mol(-1)) obtained from the virial model at zero-loading of CO2 indicates its favorable interaction with the framework. Furthermore, we have anchored small-sized Ag nanoparticles (approximate to 4-5 nm) on the COF and used the composite for chemical fixation of CO2 to alkylidene cyclic carbonates by reacting with propargyl alcohols under ambient conditions. Ag@COF catalyzes the reaction selectively with an excellent yield of 90 %. Recyclability of the catalyst has been demonstrated up to five consecutive cycles. The post-catalysis characterizations reveal the integrity of the catalyst even after five reaction cycles. This study emphasizes the ability of COF for simultaneous adsorption and chemical fixation of CO2 into corresponding cyclic carbonates.

10aCO2 capture10acovalent organic frameworks10acyclic carbonates10aPropargyl alcohols10asilver nanoparticles1 aChakraborty, Debanjan1 aShekhar, Pragalbh1 aSingh, Himan, Dev1 aKushwaha, Rinku1 aVinod, C., P.1 aVaidhyanathan, Ramanathan uhttp://library.ncl.res.in/content/ag-nanoparticles-supported-resorcinol-phenylenediamine-based-covalent-organic-framework02164nas a2200253 4500008004100000022001400041245008400055210006900139260000800208300001500216490000700231520135000238653001601588653001701604653001101621653001701632100002201649700002201671700002601693700002101719700002801740700003001768856011201798 2022 eng d a1861-472800aCoordination flexibility aided CO2-specific gating in an iron isonicotinate MOF0 aCoordination flexibility aided CO2specific gating in an iron iso cFEB ae2021013050 v173 a

Coordination flexibility assisted porosity has been introduced into an Iron-isonicotinate metal-organic framework (MOF), (Fe(4-PyC)(2) . (OH). The framework showed CO2-specific gate opening behavior, which gets tuned as a function of temperature and pressure. The MOF ` s physisorptive porosity towards CO2, CH4, and N-2 was investigated; it adsorbed only CO2 via a gate opening phenomenon. The isonicotinate, representing a borderline soft base, is bound to the hard Fe3+ centre through monodentate carboxylate and pyridyl nitrogen. This moderately weak binding enables isonicotinate to spin like a spindle under the CO2 pressure opening the gate for a sharp increase in CO2 uptake at 333 mmHg (At 298 K, the CO2 uptake increases from 0.70 to 1.57 mmol/g). We investigated the MOF ` s potential for CO2/N-2 and CO2/CH4 gas separation aided by this gating. IAST model reveals that the CO2/N-2 selectivity jumps from 325 to 3131 when the gate opens, while the CO2/CH4 selectivity increases three times. Interestingly, this Fe-isonicotinate MOF did not follow the trend set by our earlier reported Hard-Soft Gate Control (established for isostructural M2+-isonicotinate MOFs (M=Mg, Mn)). However, we account for this discrepancy using the different oxidation state of metals confirmed by X-ray photoelectron spectroscopy and magnetism.

10aCO2 capture10aflexible MOF10agating10aIsonicotinic1 aSingh, Himan, Dev1 aNandi, Shyamapada1 aChakraborty, Debanjan1 aSingh, Kirandeep1 aVinod, Chathakudath, P.1 aVaidhyanathan, Ramanathan uhttp://library.ncl.res.in/content/coordination-flexibility-aided-co2-specific-gating-iron-isonicotinate-mof02812nas a2200229 4500008004100000022001400041245013100055210006900186260000800255300001600263490000700279520198000286100002302266700002202289700001802311700002202329700001702351700002602368700002802394700003002422856013002452 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

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.

1 aChandran, Chandana1 aSingh, Himan, Dev1 aLeo, Liya, S.1 aShekhar, Pragalbh1 aRase, Deepak1 aChakraborty, Debanjan1 aVinod, Chathakudath, P.1 aVaidhyanathan, Ramanathan uhttp://library.ncl.res.in/content/covalent-organic-framework-electrodeposited-copper-nanoparticles-desirable-catalyst-ullmann02843nas a2200301 4500008004100000245017400041210006900215260000900284300001400293490000600307520174100313653001202054653001402066653003102080653002802111653001802139653002402157100003702181700002002218700001802238700002202256700002202278700002602300700003602326700003002362700001802392856013102410 2022 eng d00aSynergistic electronic effects in AuCo nanoparticles stabilized in a triazine-based covalent organic framework: a catalyst for methyl orange and methylene blue reduction0 aSynergistic electronic effects in AuCo nanoparticles stabilized  cAPR  a4744-47530 v53 a

Developing stable active catalysts for reducing water-soluble pollutants is a desirable target. In this pursuit, we have functionalized covalent organic frameworks (COFs) with gold (Au) and cobalt (Co) nanoparticles via a one-step aqueous synthesis process, and their catalytic activity in reducing methyl orange and methylene blue is examined. Operando absorbance measurements of methyl orange (anionic dye) reduction revealed AuCoCOF (1.3 Au/1.0 Co) to have superior kinetics over many other catalysts, which typically require additional external stimuli (e.g., photons) and higher catalyst loadings. After confirming the homogeneous dispersion of the nanoparticles on the COF support using three-dimensional (3D) tomography and material stability through powder X-ray diffraction (PXRD), infrared (IR), and thermal studies, we investigated their redox activity. Cyclic voltammetry (CV) confirmed the involvement of both metals in the redox process, while spectroelectrochemical measurements show that their activity and kinetics remain unaltered by an applied potential. Solid-state UV measurements reveal that the neat COF is a semiconductor with a large band gap (2.8 eV), which is substantially lowered when loaded with cobalt nanoparticles (2.2 eV for CoCOF). The electronic synergy between Au and Co nanoparticles further reduces the band gap of AuCoCOF (1.9 eV). Thus, there is a definite advantage in doping non-noble metal nanoparticles into a noble metal lattice and nanoconfining them into a porous COF support. Our study highlights the significance of bimetallic COF-supported nanocatalysts, wherein one can engage each component toward targeted applications that demand redox activity with favorable kinetics.

10aAuCoCOF10aband gaps10aCovalent organic framework10amethyl orange reduction10aNanoparticles10aUV-vis spectroscopy1 aDevulapalli, Venkata, Swaroopa D1 aKushwaha, Rinku1 aOvalle, Edwin1 aSingh, Himan, Dev1 aShekhar, Pragalbh1 aChakraborty, Debanjan1 aVinod, Chathakudath, Prabhakara1 aVaidhyanathan, Ramanathan1 aBorguet, Eric uhttp://library.ncl.res.in/content/synergistic-electronic-effects-auco-nanoparticles-stabilized-triazine-based-covalent-organic02091nas a2200277 4500008004100000245013500041210006900176260000800245300001100253490000700264520112600271100002201397700003701419700001701456700002201473700001701495700001801512700001701530700002701547700002501574700002001599700002601619700001801645700003001663856012001693 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

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.

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 uhttp://library.ncl.res.in/content/cof-supported-zirconium-oxyhydroxide-versatile-heterogeneous-catalyst-knoevenagel03137nas a2200253 4500008004100000022001400041245012100055210006900176260000900245300001200254490000600266520224700272100001702519700002702536700002202563700002202585700001802607700002602625700002102651700001902672700003202691700003002723856013002753 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

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.

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 uhttp://library.ncl.res.in/content/hydroxide-ion-conducting-viologen-bakelite-organic-frameworks-flexible-solid-state-zinc-air