@article { ISI:000309370500004, title = {Carbon dioxide capture by metal organic frameworks}, journal = {Indian Journal of Chemistry Section A-Inorganic Bio-Inorganic Physical Theoretical \& Analytical Chemistry}, volume = {51}, number = {9-10, SI}, year = {2012}, month = {SEP}, pages = {1223-1230}, publisher = {NATL INST SCIENCE COMMUNICATION-NISCAIR}, address = {DR K S KRISHNAN MARG, PUSA CAMPUS, NEW DELHI 110 012, INDIA}, abstract = {

The design and synthesis of functionalized metal organic framework materials (MOFs) for reversible physisorption of CO2 is discussed. This strategy of CO2 adsorption in MOFs requires less energy for regeneration than materials relying on chemisorption. As a result the MOFs have received considerable attention as sorbent materials for strategic gases such as CO2 and H,. In this review, we have discussed different MOFs and hybrid materials containing MOFs which can adsorb CO2 at room temperature. In order to achieve high adsorption capacity, fast CO2 adsorption-desorption and low energy requirement for regeneration are necessary. Several avenues for increasing the CO2 adsorption capacity of such materials, for instance, introduction of open metal sites and the use of ligand molecules with specific functionalities (like -OH or -NH2) have been described. It has been observed that CO2 loading capacity of MOFs increases with functionalization. Herein, we have discussed how N-containing and fluorinated MOFs are designed to achieve higher CO2 loading than their non-functionalized counterparts. Nanocarbons (e.g. carbon nanotubes, carbon nanofibres, etc.) are porous materials and a blend of these porous materials with porous MOFs or porous carbon derived from MOFs may act as a better adsorbate than even the pure materials. Enhancement of CO2 loading by nanocarbon-MOF hybrid material is also discussed.

}, keywords = {Carbon dioxide adsorbents, Carbon dioxide capture, hybrid materials, Metal organic frameworks, Nanocarbons, Porous nanocarbons}, issn = {0376-4710}, author = {Saha, Subhadeep and Chandra, Suman and Garai, Bikash and Banerjee, Rahul} } @article { ISI:000300887700023, title = {Competition between gelation and crystallisation of a peculiar multicomponent liquid system based on ammonium salts}, journal = {Soft Matter}, volume = {8}, number = {12}, year = {2012}, month = {FEB}, pages = {3446-3456}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

An exemplar competition between gelation and crystallisation phenomena was examined with an unusual synergistic multicomponent (organo) gelator solution (MGS), which consists of a well-defined methanolic solution of (1R, 2R)-1,2-diaminocyclohexane L-tartrate containing 2.4 equiv. of concentrated hydrochloric acid. The optimal composition of the MGS was determined through meticulous solubility, gelation and structural studies, which support a transient gelation mechanism based on the kinetic self-assembly of the tartrate salt driven by hydrogen-bonding interactions, involving ammonium nitrogen donors and hydroxyl oxygen acceptors, and electrostatic interactions. The hydrochloric acid is involved in the solubilisation of the salt through an ionic dissociation-exchange process, which ends up with the formation-precipitation of (1R, 2R)-1,2-diaminocyclohexane dihydrochloride. As a consequence, an irreversible destruction of the gel takes place, which indicates the metastable nature of this phase that cannot be accessed from the thermodynamically equilibrated state. Gelation of a variety of oxygenated and nitrogenated solvents with moderate polarity occurred efficiently using extremely low MGS concentrations at low temperatures, and the gel phase was confirmed by dynamic rheological measurements. Several features make the described MGS unique: (1) it is a multicomponent solution where each component and its stoichiometry play a key role in the reproducible formation and stabilization of the gels; (2) it is formed by simple, small, and commercially available chiral building blocks (dissolved in a well-defined solvent system), which are easily amenable for further modifications; (3) the gelation phenomenon takes place efficiently at low temperature upon warming up the isotropic solution, conversely to the typical gel preparation protocol; and (4) the formed organogels are not thermoreversible despite the non-covalent interactions that characterize the 3D-network.

}, issn = {1744-683X}, doi = {10.1039/c2sm07183e}, author = {Kapoor, Iti and Schoen, Eva-Maria and Bachl, Jurgen and Kuehbeck, Dennis and Cativiela, Carlos and Saha, Subhadeep and Banerjee, Rahul and Roelens, Stefano and Juan Marrero-Tellado, Jose and Diaz, David Diaz} } @article { ISI:000308310100032, title = {Control of porosity by using isoreticular zeolitic imidazolate frameworks (IRZIFs) as a template for porous carbon synthesis}, journal = {Chemistry-A European Journal}, volume = {18}, number = {36}, year = {2012}, month = {SEP}, pages = {11399-11408}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Herein, by using isoreticular zeolitic imidazolate frameworks (IRZIFs) as a template, we report the synthesis, morphology, and gas adsorption properties of porous carbon synthesized by a nanocasting method at 1000 degrees C, in which furfuryl alcohol (FA) was used as a carbon source. By using IRZIFs with variable porosity as templates, we could achieve control over the carbon porosity and H-2 and CO2 uptake. The resultant microporous carbon C-70, synthesized by using ZIF-70 as the template, is the most porous (Brunauer-Emmett-Teller (BET) surface area 1510 m(2)g(-1)). Carbon C-68, synthesized by using ZIF-68, has moderate porosity (BET surface area 1311 m(2)g(-1)), and C-69, synthesized by using ZIF-69, has the lowest porosity in this series (BET surface area 1171 m(2)g(-1)). The porous carbons C-70, C-68, and C-69, which have graphitic texture, have promising H2 uptake capacities of 2.37, 2.15, and 1.96 wt\%, respectively, at 77 K and 1 atm. Additionally, C-70, C-68, and C-69 show CO2 uptake capacities of 5.45, 4.98, and 4.54 mmolg(-1), respectively, at 273 K and 1 atm. The gas uptake trends shown by C-70, C-68, and C-69 clearly indicate the dependence of carbon porosity on the host template. Moreover, the as-synthesized carbons C-70, C-68, and C-69 show variable conductivity.

}, keywords = {Carbon, Hydrogen storage, metal-organic frameworks, microporous materials, zinc}, issn = {0947-6539}, doi = {10.1002/chem.201200957}, author = {Pachfule, Pradip and Biswal, Bishnu P. and Banerjee, Rahul} } @article { ISI:000307187300030, title = {Correlation between coordinated water content and proton conductivity in Ca-BTC-based metal-organic frameworks}, journal = {Chemical Communications}, volume = {48}, number = {70}, year = {2012}, month = {JUL}, pages = {8829-8831}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Proton conductivity of five Ca-based MOFs which depends on the amount of water molecules coordinated to the Ca-centres has been reported. These MOFs show high temperature proton conductivity due to the strong hydrogen bonding between the lattice and coordinated water molecules.

}, issn = {1359-7345}, doi = {10.1039/c2cc34006b}, author = {Mallick, Arijit and Kundu, Tanay and Banerjee, Rahul} } @article { ISI:000328099400036, title = {Chemically stable multilayered covalent organic nanosheets from covalent organic frameworks via mechanical delamination}, journal = {Journal of the American Chemical Society}, volume = {135}, number = {47}, year = {2013}, month = {NOV}, pages = {17853-17861}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A series of five thermally and chemically stable functionalized covalent organic frameworks (COFs), namely, TpPa-NO2, TpPa-F-4, TpBD-(NO2)(2), TpBD-Me-2, and TpBD-(OMe)(2) were synthesized by employing the solvothermal aldehyde-amine Schiff base condensation reaction. In order to complete the series, previously reported TpPa-1, TpPa-2, and TpBD have also been synthesized, and altogether, eight COFs were fully characterized through powder X-ray diffraction (PXRD), Fourier transform IR (FT-IR) spectroscopy, C-13 solid-state NMR spectroscopy, and thermogravimetric analysis. These COFs are crystalline, permanently porous, and stable in boiling water, acid (9 N HCl), and base (3 N NaOH). The. synthesized COFs (all eight) were successfully delaminated using a simple, safe, and environmentally friendly mechanical grinding route to transform into covalent organic nanosheets (CONs) and were well characterized via transmission electron microscopy and atomic force microscopy. Further PXRD and FT-IR analyses confirm that these CONs retain their structural integrity throughout the delamination process and also remain stable in aqueous, acidic, and basic media like the parent COFs. These exfoliated CONs have graphene-like layered morphology (delaminated layers), unlike the COFs from which they were synthesized.

}, issn = {0002-7863}, doi = {10.1021/ja408121p}, author = {Chandra, Suman and Kandambeth, Sharath and Biswal, Bishnu P. and Lukose, Binit and Kunjir, Shrikant M. and Chaudhary, Minakshi V. and BabaRao, Ravichandar and Heine, Thomas and Banerjee, Rahul} } @article { ISI:000321012900013, title = {Controlled synthesis of a catalytically active hybrid metal-oxide incorporated zeolitic imidazolate framework (MOZIF)}, journal = {Chemical Communications}, volume = {49}, number = {59}, year = {2013}, month = {JUN}, pages = {6617-6619}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A rare hybrid Metal-Oxide incorporated Zeolitic Imidazolate Framework, MOZIF-1, containing tetrahedral Zn(II) and Mo(VI) centres has been synthesized. MOZIF-1 can degrade methyl orange and orange II dyes under visible light. Na-3[PMo12O40] is the source of Mo(VI) in MOZIF-1.

}, issn = {1359-7345}, doi = {10.1039/c3cc42904k}, author = {Dey, Chandan and Banerjee, Rahul} } @article {46387, title = {Chemically delaminated free standing covalent organic nanosheets (CONs)}, journal = {Acta Crystallographica A-Foundation and Advances}, volume = {70}, year = {2014}, month = {MAY}, pages = {C457}, type = {Meeting Abstract}, keywords = {Covalent organic framework, porous polymers, ultra thin nano sheets}, issn = {2053-2733}, author = {Khayum, Abdul M. and Banerjee, Rahul} } @article {46373, title = {Chemically stable urea based COF for size selective heterogeneous catalysis}, journal = {Acta Crystallographica A-Foundation and Advances}, volume = {70}, year = {2014}, month = {FEB}, pages = {C1146}, type = {Meeting Abstract}, keywords = {chemical stability, Covalent organic framework, heterogeneous catalysis}, issn = {2053-2733}, author = {Basu, Arghya and Banerjee, Rahul} } @article {46386, title = {Construction of highly crystalline ultraporous covalent organic frameworks in seconds}, journal = {Acta Crystallographica A-Foundation and Advances}, volume = {70}, year = {2014}, month = {APR}, pages = {C456}, type = {Meeting Abstract}, keywords = {COFs, Crystalline, Ultraporous}, issn = {2053-2733}, author = {Karak, Suvendu and Banerjee, Rahul} } @article {46381, title = {Covalent organic framework thin-films for molecular separation}, journal = {Acta Crystallographica A-Foundation and Advances}, volume = {70}, year = {2014}, month = {MAY}, pages = {C547}, type = {Meeting Abstract}, keywords = {Covalent organic framework, Separation, Thin-films}, issn = {2053-2733}, author = {Dey, Kaushik and Banerjee, Rahul} } @article { ISI:000345234900039, title = {Covalent organic framework-cadmium sulfide hybrid as a prototype photocatalyst for visible-light-driven hydrogen production}, journal = {Chemistry A-European Journal}, volume = {20}, number = {48}, year = {2014}, month = {NOV}, pages = {15961-15965}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

CdS nanoparticles were deposited on a highly stable, two-dimensional (2D) covalent organic framework (COF) matrix and the hybrid was tested for photocatalytic hydrogen production. The efficiency of CdS-COF hybrid was investigated by varying the COF content. On the introduction of just 1 wt\% of COF, a dramatic tenfold increase in the overall photocatalytic activity of the hybrid was observed. Among the various hybrids synthesized, that with 10 wt\% COF, named CdS-COF (90: 10), was found to exhibit a steep H2 production amounting to 3678 mmolh(-1) g(-1), which is significantly higher than that of bulk CdS particles (124 mmolh(-1)g(-1)). The presence of a p-conjugated backbone, high surface area, and occurrence of abundant 2D hetero-interface highlight the usage of COF as an effective support for stabilizing the generated photoelectrons, thereby resulting in an efficient and high photocatalytic activity.

}, keywords = {charge transfer, covalent organic frameworks, hybrid materials, hydrogen production, Photocatalysis}, issn = {0947-6539}, doi = {10.1002/chem.201403800}, author = {Thote, Jayshri and Aiyappa, Harshitha Barike and Deshpande, Aparna and Diaz, David Diaz and Kurungot, Sreekumar and Banerjee, Rahul} } @article { ISI:000330340200002, title = {Crystalline metal-organic frameworks (MOFs): synthesis, structure and function}, journal = {Acta Crystallographica Section B-Structural Science}, volume = {70}, number = {1, SI}, year = {2014}, month = {FEB}, pages = {3-10}, publisher = {WILEY-BLACKWELL}, type = {Article}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {

Metal-organic frameworks (MOFs) are a class of hybrid network supramolecular solid materials comprised of organized organic linkers and metal cations. They can display enormously high surface areas with tunable pore size and functionality, and can be used as hosts for a range of guest molecules. Since their discovery, MOFs have experienced widespread exploration for their applications in gas storage, drug delivery and sensing. This article covers general and modern synthetic strategies to prepare MOFs, and discusses their structural diversity and properties with respect to application perspectives.

}, issn = {0108-7681}, doi = {10.1107/S2052520613029557}, author = {Dey, Chandan and Kundu, Tanay and Biswal, Bishnu P. and Mallick, Arijit and Banerjee, Rahul} } @article {46394, title = {Crystalline porous materials for gas adsorption}, journal = {Acta Crystallographica A-Foundation and Advances}, volume = {70}, year = {2014}, month = {MAY}, pages = {C463}, type = {Meeting Abstract}, keywords = {Covalent organic framework, gas adsorption}, issn = {2053-2733}, author = {Pal, Tapan Kumar and Banerjee, Rahul} } @article { ISI:000356176200034, title = {Chemical sensing in two dimensional porous covalent organic nanosheets}, journal = {Chemical Science}, volume = {6}, number = {7}, year = {2015}, month = {APR}, pages = {3931-3939}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Two new imide-based crystalline, porous, and chemically stable covalent organic frameworks (COFs) (TpBDH and TfpBDH) have been successfully synthesized employing solvothermal crystallization route. Furthermore, thin layered covalent organic nanosheets (CONs) were derived from these bulk COFs by the simple liquid phase exfoliation method. These 2D CONs showcase increased luminescence intensity compared to their bulk counterparts (COFs). Notably, TfpBDH-CONs showcase good selectivity and prominent, direct visual detection towards different nitroaromatic analytes over TpBDH-CONs. Quite interestingly, TfpBDH-CONs exhibit a superior {\textquoteleft}{\textquoteleft}turn-on{\textquoteright}{\textquoteright} detection capability for 2,4,6-trinitrophenol (TNP) in the solid state, but conversely, they also show a {\textquoteleft}{\textquoteleft}turn-off{\textquoteright}{\textquoteright} detection in the dispersion state. These findings describe a new approach towards developing an efficient, promising fluorescence chemosensor material for both visual and spectroscopic detection of nitroaromatic compounds with very low [10(-5) (M)] analyte concentrations.

}, issn = {2041-6520}, doi = {10.1039/c5sc00512d}, author = {Das, Gobinda and Biswal, Bishnu P. and Kandambeth, Sharath and Venkatesh, V. and Kaur, Gagandeep and Addicoat, Matthew A. and Heine, Thomas and Verma, Sandeep and Banerjee, Rahul} } @article {43415, title = {Chemically delaminated free-standing ultrathin covalent organic nanosheets}, journal = {Angewandte Chemie-International Edition}, volume = {55}, year = {2016}, month = {DEC}, pages = {15604-15608}, abstract = {Covalent organic nanosheets (CONs) are a new class of porous thin two-dimensional (2D) nanostructures that can be easily designed and functionalized and could be useful for separation applications. Poor dispersion, layer restacking, and difficult postsynthetic modifications are the major hurdles that need to be overcome to fabricate scalable CON thin films. Herein, we present a unique approach for the chemical exfoliation of an anthracene-based covalent organic framework (COF) to N-hexylmaleimide-functionalized CONs, to yield centimeter-sized free-standing thin films through layer-by-layer CON assembly at the air-water interface. The thinlayer fabrication technique presented here is simple, scalable, and does not require any surfactants or stabilizing agents.}, doi = {10.1002/anie.201607812}, author = {Khayum, M. Abdul and Kandambeth, Sharath and Mitra, Shouvik and Nair, Sanoop B. and Das, Anuja and Nagane, Samadhan S. and Mukherjee, Rabibrata and Banerjee, Rahul} } @article { ISI:000373163100005, title = {Chemically stable covalent organic framework (COF)-polybenzimidazole hybrid membranes: enhanced gas separation through pore modulation}, journal = {Chemistry-A European Journal}, volume = {22}, number = {14}, year = {2016}, month = {MAR}, pages = {4695-4699}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

Highly flexible, TpPa-1@PBI-BuI and TpBD@PBI-BuI hybrid membranes based on chemically stable covalent organic frameworks (COFs) could be obtained with the polymer. The loading obtained was substantially higher (50\%) than generally observed with MOFs. These hybrid membranes show an exciting enhancement in permeability (about sevenfold) with appreciable separation factors for CO2/N-2 and CO2/CH4. Further, we found that with COF pore modulation, the gas permeability can be systematically enhanced.

}, keywords = {covalent organic frameworks, Gas separation, membranes, microporous materials, pore modulation}, issn = {0947-6539}, doi = {10.1002/chem.201504836}, author = {Biswal, Bishnu P. and Chaudhari, Harshal D. and Banerjee, Rahul and Kharul, Ulhas K.} } @article { ISI:000378973100031, title = {Cobalt-modified covalent organic framework as a robust wateroxidation electrocatalyst}, journal = {Chemistry of Materials}, volume = {28}, number = {12}, year = {2016}, month = {JUN}, pages = {4375-4379}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

The development of stable, efficient oxygen evolution reaction (OER) catalyst capable of oxidizing water is one of the premier challenges in the conversion of solar energy to electrical energy, because of its poor kinetics. Herein, a bipyridine-containing covalent organic framework (TpBpy) is utilized as an OER catalyst by way of engineering active Co(II) ions into its porous framework. The as-obtained Co-TpBpy retains a highly accessible surface area (450 m(2)/g) with exceptional stability, even after 1000 cycles and 24 h of OER activity in phosphate buffer under neutral pH conditions with an overpotential of 400 mV at a current density of 1 mA/cm(2). The unusual catalytic stability of Co-TpBpy arises from the synergetic effect of the inherent porosity and presence of coordinating units in the COF skeleton.

}, issn = {0897-4756}, doi = {10.1021/acs.chemmater.6b01370}, author = {Aiyappa, Harshitha Barike and Thote, Jayshri and Shinde, Digambar Balaji and Banerjee, Rahul and Kurungot, Sreekumar} } @article {43442, title = {Constructing covalent organic frameworks in water via dynamic covalent bonding}, journal = {Iucrj}, volume = {3}, year = {2016}, month = {NOV}, pages = {402-407}, abstract = {The formation of keto-enamine based crystalline, porous polymers in water is investigated for the first time. Facile access to the Schiff base reaction in water has been exploited to synthesize stable porous structures using the principles of Dynamic Covalent Chemistry (DCC). Most credibly, the water-based Covalent Organic Frameworks (COFs) possess chemical as well as physical properties such as crystallinity, surface area and porosity, which is comparable to their solvothermal counterparts. The formation of COFs in water is further investigated by understanding the nature of the monomers formed using hydroxy and non-hydroxy analogues of the aldehyde. This synthetic route paves a new way to synthesize COFs using a viable, greener route by utilization of the DCC principles in conjunction with the keto-enol tautomerism to synthesize useful, stable and porous COFs in water.}, doi = {10.1107/S2052252516013762}, author = {Thote, Jayshri and Aiyappa, Harshitha Barike and Kumar, Raya Rahul and Kandambeth, Sharath and Biswal, Bishnu P. and Shinde, Digambar Balaji and Roy, Neha Chaki and Banerjee, Rahul} } @article {43909, title = {Covalent organic frameworks and organic cage structures}, journal = {CrystEngComm}, volume = {19}, year = {2017}, month = {SEP}, chapter = {4866-4867}, issn = {1466-8033}, doi = {10.1039/c7ce90115a}, author = {Banerjee, Rahul and Champness, Neil R.} } @article {45421, title = {Convergent covalent organic framework thin sheets as flexible supercapacitor electrodes}, journal = {ACS Applied Material \& Interfaces}, volume = {10}, year = {2018}, month = {AUG}, pages = {28139-28146}, type = {Article}, abstract = {Flexible supercapacitors in modern electronic equipment require light-weight electrodes, which have a high surface area, precisely integrated redox moieties, and mechanically strong flexible free-standing nature. However, the incorporation of the aforementioned properties into a single electrode remains a great task. Herein, we could overcome these challenges by a facile and scalable synthesis of the convergent covalent organic framework (COF) free-standing flexible thin sheets through solid-state molecular baking strategy. Here, redox-active anthraquinone (Dq) and pi-electron-rich anthracene (Da) are judiciously selected as two different linkers in a beta-ketoenamine-linked two-dimensional (2D) COF. As a result of precisely integrated anthraquinone moieties, COF thin sheet exhibits redox activity. Meanwhile, pi-electron-rich anthracene linker assists to improve the mechanical property of the free-standing thin sheet through the enhancement of noncovalent interaction between crystallites. This binder-free strategy offers the togetherness of crystallinity and flexibility in 2D COF thin sheets. Also, the synthesized porous crystalline convergent COF thin sheets are benefited with crack-free uniform surface and light-weight nature. Further, to demonstrate the practical utility of the material as an electrode in energy-storage systems, we fabricated a solid-state symmetrical flexible COF supercapacitor device using a GRAFOIL peeled carbon tape as the current collector.}, doi = {10.1021/acsami.8b10486}, author = {Khayum, Abdul M. and Vijayakumar, Vidyanand and Karak, Suvendu and Kandambeth, Sharath and Bhadra, Mohitosh and Suresh, Karthika and Acharambath, Nikhil and Kurungot, Sreekumar and Banerjee, Rahul} } @article {46219, title = { Covalent organic frameworks: chemistry beyond the structure }, journal = {Journal of the American Chemical Society}, volume = {141}, year = {2019}, month = {FEB}, pages = {1807-1822}, type = {Article}, abstract = {

Covalent organic frameworks (COFs) represent a new field of rapidly growing chemical research that takes direct inspiration from diverse covalent bonds existing between atoms. The success of linking atoms in two and three dimensions to construct extended framework structures moved the chemistry of COFs beyond the structures to methodologies, highlighting the possibility of prospective applications. Although structure to property relation in COFs has led to fascinating properties, chemical stability, processability and scalability were some of the important challenges that needed to be overcome for their successful implementation. In this Perspective, we take a closer look at the growth of COFs from mere supramolecular structures to potential industrializable materials.

}, doi = { 10.1021/jacs.8b10334}, author = {Kandambeth, Sharath and Dey, Kaushik and Banerjee, Rahul} } @article {46413, title = {Covalent self-assembly in two dimensions: connecting covalent organic framework nanospheres into crystalline and porous thin films}, journal = {Journal of the American Chemical Society}, volume = {141}, year = {2019}, month = {DEC }, pages = {20379}, type = {Article}, chapter = {20371}, abstract = {

Insolubility of covalent organic frameworks (COFs) in organic solvents is one of the major obstacles for the potential application of these extended networks such as drug delivery, sensing, optoelectronics, and semiconductor device fabrication. The present work proposes a unique way to make uniform, solution-processable, crystalline, and porous COF nanospheres directly from the homogeneous solution of amine and aldehyde via spatial and temporal control of the nucleation and growth. This strategy of direct nucleation simultaneously showcases the caliber to tune the size of the COF nanospheres from 25 to 570 nm. We have also demonstrated the concept of mesoscale covalent self-assembly of those solution-processable COF nanospheres in the liquid-liquid interface (DCM-water bilayer) for the very first time, transmuting them into self-standing COF thin films with long-range ordered arrangements in two dimensions. The crystalline and porous (with TpAzo showing highest S-BET of 1932 m(2) g(-1)) free-standing COF thin films could be fabricated in a wide range of thicknesses from as low as 21 nm to as high as 630 nm. Both beta-ketoenamine (TpAzo, TpDPP) and imine (TpOMeAzo, TpOMeDPP) linked COF thin films have been synthesized via mesoscale covalent self-assembly of the solution-processable COF nanospheres illustrating the generality of this eloquent methodology. Further, the solution processability has been tested and utilized to cast COF thin films uniformly in the inner and outer surface of an alumina hollow fiber membrane. The COF thin film-alumina hollow fiber membrane composites have showcased promising selective molecular separation of He and O-2, He and CO2, and He and N-2.

}, issn = {0002-7863}, doi = {10.1021/jacs.9b10788}, author = {Sasmal, Himadri Sekhar and Halder, Arjun and Kunjattu, Shebeeb and Dey, Kaushik and Nadol, Athulya and Ajithkumar, Thalasseril G. and Bedadur, Prachiti Ravindra and Banerjee, Rahul} } @article {46867, title = {Connecting microscopic structures, mesoscale assemblies, and macroscopic architectures in 3D-printed hierarchical porous covalent organic framework foams}, journal = {Journal of the American Chemical Society}, volume = {142}, year = {2020}, month = {MAY }, pages = {8252-8261}, type = {Article}, abstract = {

The induction of macro and mesopores into two-dimensional porous covalent organic frameworks (COFs) could enhance the exposure of the intrinsic micropores toward the pollutant environment, thereby, improving the performance. However, the challenge is to build a continuous hierarchically porous macro-architecture of crystalline organic materials in the bulk scale. In this regard, we have strategized a novel synthetic method to create hierarchically porous COF foams consisting of ordered micropores (2-2.2 nm) and disordered meso and macropores (50 nm to 200 mu m) as well as ordered macropores (1.5 mm to 2 cm). Herein, graphene oxide was used for creating disordered macro and mesopores in COF-GO foams. Considering the rheological features of the precursor hydrogel, we could integrate crystalline and porous COF-GO foams into self-supported three-dimensional (3D)-printed objects with the desired shapes and sizes. Therefore, we have engineered the 3D macro-architecture of COF-GO foams into complex geometries keeping their structural order and continuous porosity intact over a range of more than a million (10(-9) m to 10(-3) m). The interconnected 3D openings in these COF-GO foams further enhance the rapid and efficient uptake of organic and inorganic pollutants from water (\>95\% removal within 30 s). The abundant distribution of interconnected macroporous volume (55\%) throughout the COF-GO foam matrix enhances the flow of water (1.13 x 10(-3) m.s(-1)) which results in efficient mass transport and adsorption.

}, issn = {0002-7863}, doi = {10.1021/jacs.0c00555}, author = {Mohammed, Abdul Khayum and Usgaonkar, Saurabh and Kanheerampockil, Fayis and Karak, Suvendu and Halder, Arjun and Tharkar, Minakshi and Addicoat, Matthew and Ajithkumar, Thalasseril G. and Banerjee, Rahul} } @article {48745, title = {Covalent organic framework cladding on peptide-amphiphile-based biomimetic catalysts}, journal = {Journal of the American Chemical Society}, volume = {145}, year = {2023}, month = {JUN }, pages = {12793-12801}, type = {Article}, abstract = {

Peptide-based biomimetic catalysts are promising materialsforefficient catalytic activity in various biochemical transformations.However, their lack of operational stability and fragile nature innon-aqueous media limit their practical applications. In this study,we have developed a cladding technique to stabilize biomimetic catalystswithin porous covalent organic framework (COF) scaffolds. This methodologyallows for the homogeneous distribution of peptide nanotubes insidethe COF (TpAzo and TpDPP) backbone, creating strong noncovalent interactionsthat prevent leaching. We synthesized two different peptide-amphiphiles,C10FFVK and C10FFVR, with lysine (K) and arginine(R) at the C-termini, respectively, which formed nanotubular morphologies.The C10FFVK peptide-amphiphile nanotubes exhibit enzyme-likebehavior and efficiently catalyze C-C bond cleavage in a buffermedium (pH 7.5). We produced nanotubular structures of TpAzo-C10FFVK and TpDPP-C10FFVK through COF claddingby using interfacial crystallization (IC). The peptide nanotubes encasedin the COF catalyze C-C bond cleavage in a buffer medium aswell as in different organic solvents (such as acetonitrile, acetone,and dichloromethane). The TpAzo-C10FFVK catalyst,being heterogeneous, is easily recoverable, enabling the reactionto be performed for multiple cycles. Additionally, the synthesis ofTpAzo-C10FFVK thin films facilitates catalysis inflow. As control, we synthesized another peptide-amphiphile, C10FFVR, which also forms tubular assemblies. By depositingTpAzo COF crystallites on C10FFVR nanotubes through IC,we produced TpAzo-C10FFVR nanotubular structuresthat expectedly did not show catalysis, suggesting the critical roleof the lysines in the TpAzo-C10FFVK.

}, issn = {0002-7863}, doi = {10.1021/jacs.3c03562}, author = {Kumar Mahato, Ashok and Pal, Sumit and Dey, Kaushik and Reja, Antara and Paul, Satyadip and Shelke, Ankita and Ajithkumar, Thalasseril G. and Das, Dibyendu and Banerjee, Rahul} } @article {48833, title = {Covalent organic framework thin-film photodetectors from solution-processable porous nanospheres}, journal = {Journal of the American Chemical Society}, volume = {145}, year = {2023}, month = {JAN}, pages = {1649-1659}, type = {Article}, abstract = {

The synthesis of homogeneous covalent organic framework (COF) thin films on a desired substrate with decent crystallinity, porosity, and uniform thickness has great potential for optoelectronic applications. We have used a solution-processable sphere transmutation process to synthesize 300 +/- 20 nm uniform COF thin films on a 2 x 2 cm2 TiO2-coated fluorine-doped tin oxide (FTO) surface. This process controls the nucleation of COF crystallites and molecular morphology that helps the nanospheres to arrange periodically to form homogeneous COF thin films. We have synthesized four COF thin films (TpDPP, TpEtBt, TpTab, and TpTta) with different functional backbones. In a close agreement between the experiment and density functional theory, the TpEtBr COF film showed the lowest optical band gap (2.26 eV) and highest excited-state lifetime (8.52 ns) among all four COF films. Hence, the TpEtBr COF film can participate in efficient charge generation and separation. We constructed optoelectronic devices having a glass/FTO/TiO2/COF-film/Au architecture, which serves as a model system to study the optoelectronic charge transport properties of COF thin films under dark and illuminated conditions. Visible light with a calibrated intensity of 100 mW cm-2 was used for the excitation of COF thin films. All of the COF thin films exhibit significant photocurrent after illumination with visible light in comparison to the dark. Hence, all of the COF films behave as good photoactive substrates with minimal pinhole defects. The fabricated out-of-plane photodetector device based on the TpEtBr COF thin film exhibits high photocurrent density (2.65 +/- 0.24 mA cm-2 at 0.5 V) and hole mobility (8.15 +/- 0.64 x10-3 cm2 V-1 S-1) compared to other as synthesized films, indicating the best photoactive characteristics.

}, issn = {0002-7863}, doi = {10.1021/jacs.2c09838}, author = {Bag, Saikat and Sasmal, Himadri Sekhar and Chaudhary, Sonu Pratap and Dey, Kaushik and Blaette, Dominic and Guntermann, Roman and Zhang, Yingying and Poloz, Miroslav and Kuc, Agnieszka and Shelke, Ankita and Vijayaraghavan, Ratheesh K. and Ajithkumar, Thalasseril G. and Bhattacharyya, Sayan and Heine, Thomas and Bein, Thomas and Banerjee, Rahul} }