00589nas a2200181 4500008004100000022001400041245006700055210006600122260000800188300000900196490000700205653003100212653001500243653001500258100001700273700002000290856009700310 2014 eng d a2053-273300aCovalent organic framework thin-films for molecular separation0 aCovalent organic framework thinfilms for molecular separation cMAY aC5470 v7010aCovalent organic framework10aSeparation10aThin-films1 aDey, Kaushik1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/covalent-organic-framework-thin-films-molecular-separation01777nas a2200205 4500008004100000022001400041245009400055210006900149260007100218300001400289490000700303520101700310100001901327700001701346700001701363700002601380700001801406700002001424856012701444 2016 eng d a0897-475600aInterplaying intrinsic and extrinsic proton conductivities in covalent organic frameworks0 aInterplaying intrinsic and extrinsic proton conductivities in co a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR a1489-14940 v283 a

A sulfonic-acid-based covalent organic framework (TpPa-SO3H) has been synthesized that exhibits intrinsic proton conductivity under anhydrous conditions. The sulfonic acid groups are aligned on the two-dimensional (2D) layers at periodic intervals and promote the proton hopping inside the hexagonal one-dimensional channel. The intrinsic proton conductivity of TpPa-SO3H was measured as 1.7 X 10(-5) S cm(-1) at 120 degrees C under anhydrous conditions. To enhance the proton conductivity, we have synthesized a hybrid COF TpPa(SO3H-Py) by a ligand-based solid-solution approach that contains sulfonic acid as the acidic site, as well as pyridine as the basic site, in order to immobilize acidic proton carrier molecules. Impregnation of phytic acid molecules inside the framework increases the anhydrous proton conductivity up to 5 x 10(-4) S cm(-1) at 120 degrees C. Such an approach highlights the advantage and first-time use of hybrid COF for interplaying intrinsic to extrinsic proton conductivity.

1 aChandra, Suman1 aKundu, Tanay1 aDey, Kaushik1 aAddicoat, Matthew, A.1 aHeine, Thomas1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/interplaying-intrinsic-and-extrinsic-proton-conductivities-covalent-organic-frameworks-002051nas a2200157 4500008004100000245006600041210006300107260000800170300001400178490000800192520153700200100002401737700001701761700002001778856009501798 2019 eng d00a Covalent organic frameworks: chemistry beyond the structure 0 aCovalent organic frameworks chemistry beyond the structure cFEB a1807-18220 v1413 a

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.

1 aKandambeth, Sharath1 aDey, Kaushik1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/covalent-organic-frameworks-chemistry-beyond-structure-002544nas a2200229 4500008004100000022001400041245013500055210006900190260000900259300001000268490000800278520171400286100002802000700001802028700002202046700001702068700001902085700003202104700003202136700002002168856012602188 2019 eng d a0002-786300aCovalent self-assembly in two dimensions: connecting covalent organic framework nanospheres into crystalline and porous thin films0 aCovalent selfassembly in two dimensions connecting covalent orga cDEC  a203790 v1413 a

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.

1 aSasmal, Himadri, Sekhar1 aHalder, Arjun1 aKunjattu, Shebeeb1 aDey, Kaushik1 aNadol, Athulya1 aAjithkumar, Thalasseril, G.1 aBedadur, Prachiti, Ravindra1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/covalent-self-assembly-two-dimensions-connecting-covalent-organic-framework-nanospheres02492nas a2200217 4500008004100000022001400041245014700055210006900202260000900271300001400280490000800294520171100302100001902013700001702032700001702049700001802066700001702084700002702101700002002128856012602148 2019 eng d a0002-786300aInducing disorder in order: hierarchically porous covalent organic framework nanostructures for rapid removal of persistent organic pollutants0 aInducing disorder in order hierarchically porous covalent organi cMAY  a7572-75810 v1413 a

The key factor responsible for fast diffusion and mass transfer through a porous material is the availability of a widely open pore interior having complete accessibility from their surface. However, because of their highly stacked nature, ordered two-dimensional (2D) materials fail to find real-world applicability, as it is difficult to take advantage of their complete structure, especially the inner cores. In this regard, three-dimensional (3D) nanostructures constructed from layered two-dimensional crystallites could prove to be advantageous. However, the real challenge is to cultivate a porous nanostructure with ordered pores where the pores are surrounded by crystalline walls. Herein, a simple yet versatile in situ gas-phase foaming technique has been employed to address these cardinal issues. The use of baking soda leads to the continuous effervescence of CO2 during the crystallization of foam, which creates ripples and fluctuations on the surface of the 2D crystallites. The induction of ordered micropores within the disordered 3D architecture synergistically renders fast diffusion of various guests through the interconnected pore network. The high-density defects in the hierarchically porous structure help in ultrafast adsorption (<10 s) of various pollutants (removal efficiency of 99%) from water, all of which would lead to significant environmental benefit. The pseudo-second-order rate constant for the BPA pollutant is 182.3 g mg(-1) min(-1), which is the highest among all the literature reports to date. The high removal efficiency (highest efficiency of 94% and average efficiency of 70%) of a persistent organic pollutant has been attended for the first time.

1 aKarak, Suvendu1 aDey, Kaushik1 aTorris, Arun1 aHalder, Arjun1 aBera, Saibal1 aKanheerampockil, Fayis1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/inducing-disorder-order-hierarchically-porous-covalent-organic-framework-nanostructures02416nas a2200289 4500008004100000022001400041245009500055210006900150260000800219300001400227490000700241520151000248653002301758653001501781653001801796653001701814653002301831100001701854700001701871700001901888700001801907700001901925700001901944700002201963700002001985856012102005 2019 eng d a1433-785100aPorosity switching in polymorphic porous organic cages with exceptional chemical stability0 aPorosity switching in polymorphic porous organic cages with exce cMAR a4243-42470 v583 a

Porous solids that can be switched between different forms with distinct physical properties are appealing candidates for separation, catalysis, and host-guest chemistry. In this regard, porous organic cages (POCs) are of profound interest because of their solution-state accessibility. However, the application of POCs is limited by poor chemical stability. Synthesis of an exceptionally stable imine-linked (4+6) porous organic cage (TpOMe-CDA) is reported using 2,4,6-trimethoxy-1,3,5-triformyl benzene (TpOMe) as a precursor aldehyde. Introduction of the -OMe functional group to the aldehyde creates significant steric and hydrophobic characteristics in the environment around the imine bonds that protects the cage molecules from hydrolysis in the presence of acids or bases. The electronic effect of the -OMe group also plays an important role in enhancing the stability of the reported POCs. As a consequence, TpOMe-CDA reveals exceptional chemical stability in neutral, acidic and basic conditions, even in 12m NaOH. Interestingly, TpOMe-CDA exists in three different porous and non-porous polymorphic forms (, , and ) with respect to differences in crystallographic packing and the orientation of the flexible methoxy groups. All of the polymorphs retain their crystallinity even after treatment with acids and bases. All the polymorphs of TpOMe-CDA differ significantly in their properties as well as morphology and could be reversibly switched in the presence of an external stimulus.

10achemical stability10aMorphology10aorganic cages10apolymorphism10aporosity switching1 aBera, Saibal1 aDey, Kaushik1 aPal, Tapan, K.1 aHalder, Arjun1 aTothadi, Srinu1 aKarak, Suvendu1 aAddicoat, Matthew1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/porosity-switching-polymorphic-porous-organic-cages-exceptional-chemical-stability01807nas a2200253 4500008004100000022001400041245008800055210006900143260000900212300001600221490000700237520096600244653001901210653002501229653003801254653002601292653001801318100001901336700002001355700001701375700002201392700002001414856011901434 2020 eng d a1944-824400aMorphological evolution of two-dimensional porous hexagonal trimesic acid framework0 aMorphological evolution of twodimensional porous hexagonal trime cAPR  a15588-155940 v123 a

Hexagonal single crystal structure (Form II) of trimesic acid (TMA) has been isolated by dissolving the interpenetrated Form I of TMA in tetrahydrofuran. Form II (hexagonal) was converted to Form I (interpenetrated) at room temperature through some intermediate structures. A detailed time-dependent FESEM study shows that the external morphology of Form II (hexagonal) is a hollow hexagonal tube that mimics its crystal structure. The block-shaped (morphology) of Form I (interpenetrated) was converted to the hollow hexagonal tube through some intermediate morphologies which are corresponding to particular crystal structures. Here, we have established a strong correlation between crystal structures with the morphology. These hollow tubes have been employed for Rhodamine B dye adsorption studies and showed an uptake of 82%, much more significant than Form I (interpenetrated) (39%) due to the presence of a pore channel in the crystal structure.

10adye adsorption10ahollow hexagonal rod10ahydrogen-bonded organic framework10amorphology evaluation10atrimesic acid1 aTothadi, Srinu1 aKoner, Kalipada1 aDey, Kaushik1 aAddicoat, Matthew1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/morphological-evolution-two-dimensional-porous-hexagonal-trimesic-acid-framework01826nas a2200241 4500008004100000022001400041245009800055210006900153260000800222300001400230490000700244520101400251653003201265653001001297653001501307653001801322653003001340100001701370700002601387700002501413700002001438856012601458 2020 eng d a1433-785100aNanoparticle size-fractionation through self-standing porous covalent organic framework films0 aNanoparticle sizefractionation through selfstanding porous coval cJAN a1161-11650 v593 a

Covalent organic frameworks (COFs) have attracted attention due to their ordered pores leading to important industrial applications like storage and separation. Combined with their modular synthesis and pore engineering, COFs could become ideal candidates for nanoseparations. However, the fabrication of these microcrystalline powders as continuous, crack-free, robust films remains a challenge. Herein, we report a simple, slow annealing strategy to construct centimeter-scale COF films (Tp-Azo and Tp-TTA) with micrometer thickness. The as-synthesized films are porous (SA(BET)=2033 m(2) g(-1) for Tp-Azo) and chemically stable. These COFs have distinct size cut-offs (ca. 2.7 and ca. 1.6 nm for Tp-Azo and Tp-TTA, respectively), which allow the size-selective separation of gold nanoparticles. Unlike, other conventional membranes, the durable structure of the COF films allow for excellent recyclability (up to 4 consecutive cycles) and easy recovery of the gold nanoparticles from the solution.

10acovalent organic frameworks10afilms10ananofilter10aNanoparticles10asize-selective separation1 aDey, Kaushik1 aKunjattu, Shebeeb, H.1 aChahande, Anurag, M.1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/nanoparticle-size-fractionation-through-self-standing-porous-covalent-organic-framework02470nas a2200229 4500008004100000022001400041245009400055210006900149260000800218300001200226490000800238520170800246100002001954700001701974700002001991700001902011700001602030700003202046700001702078700002002095856012502115 2022 eng d a0002-786300aDual nanomechanics in anisotropic porous covalent organic framework janus-type thin films0 aDual nanomechanics in anisotropic porous covalent organic framew cJAN a400-4090 v1443 a

Empowered by crystalline ordered structures and homogeneous fabrication techniques, covalent organic frameworks (COFs) have been realized with uniform morphologies and isotropic properties. However, such homogeneity often hinders various surface-dependent properties observed in asymmetric nanostructures. The challenge remains to induce heterogeneity in COFs by creating an asymmetric superstructure such as a Janus thin film. In this regard, we propose a versatile yet straightforward interfacial layer-grafting strategy to fabricate free-standing Janus-type COF-graphene thin films. Herein, two-dimensional graphene sheets were utilized as the suitable grafter due to the possibility of noncovalent interactions between the layers. The versatility of the approach was demonstrated by fabricating two distinct Janus-type films, with the COF surface interwoven with nanofibers and nanospheres. The Janus-type films showcase opposing surface morphologies originating from graphene sheets and COF nanofibers or nanospheres, preserving the porosity (552-600 m(2) g(-1)). The unique surface chemistries of the constituent layers further endow the films with orthogonal mechanical properties, as confirmed by the nanoindentation technique. Interestingly, the graphene sheets favor the Janus-type assembly of COF nanofibers over the nanospheres. This is reflected in the better nanomechanical properties of COFfiber-graphene films (E-gra(phene) = 300-1200 MPa; E-COF( )= 15-60 MPa) compared to the COFsphere-graphene films (E-gra(phe)ne = 11-14 MPa; E-CO(F )= 2-5 MPa). These results indicate a direct relationship between the mechanical properties and homo/heterogeneity of Janus-type COF films.

1 aMohata, Shibani1 aDey, Kaushik1 aBhunia, Surojit1 aThomas, Neethu1 aGowd, Bhoje1 aAjithkumar, Thalasseril, G.1 aReddy, Malla1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/dual-nanomechanics-anisotropic-porous-covalent-organic-framework-janus-type-thin-films02541nas a2200241 4500008004100000022001400041245008900055210006900144260000900213300001600222490000800238520175100246100002501997700001502022700001702037700001702054700001902071700001902090700003202109700001802141700002002159856012002179 2023 eng d a0002-786300aCovalent organic framework cladding on peptide-amphiphile-based biomimetic catalysts0 aCovalent organic framework cladding on peptideamphiphilebased bi cJUN  a12793-128010 v1453 a

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.

1 aMahato, Ashok, Kumar1 aPal, Sumit1 aDey, Kaushik1 aReja, Antara1 aPaul, Satyadip1 aShelke, Ankita1 aAjithkumar, Thalasseril, G.1 aDas, Dibyendu1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/covalent-organic-framework-cladding-peptide-amphiphile-based-biomimetic-catalysts02902nas a2200325 4500008004100000022001400041245010100055210006900156260000800225300001400233490000800247520183600255100001602091700002802107700002802135700001702163700002102180700002202201700002002223700002002243700001902263700001902282700003302301700003202334700002502366700001802391700001702409700002002426856013002446 2023 eng d a0002-786300aCovalent organic framework thin-film photodetectors from solution-processable porous nanospheres0 aCovalent organic framework thinfilm photodetectors from solution cJAN a1649-16590 v1453 a

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.

1 aBag, Saikat1 aSasmal, Himadri, Sekhar1 aChaudhary, Sonu, Pratap1 aDey, Kaushik1 aBlaette, Dominic1 aGuntermann, Roman1 aZhang, Yingying1 aPoloz, Miroslav1 aKuc, Agnieszka1 aShelke, Ankita1 aVijayaraghavan, Ratheesh, K.1 aAjithkumar, Thalasseril, G.1 aBhattacharyya, Sayan1 aHeine, Thomas1 aBein, Thomas1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/covalent-organic-framework-thin-film-photodetectors-solution-processable-porous-nanospheres02676nas a2200265 4500008004100000022001400041245008300055210006900138260000900207300001400216490000700230520184900237100001902086700001602105700001702121700002502138700001602163700001702179700001602196700001902212700002602231700002002257700002002277856011302297 2023 eng d a2041-652000aHierarchical covalent organic framework-foam for multi-enzyme tandem catalysis0 aHierarchical covalent organic frameworkfoam for multienzyme tand cJUN  a6643-66530 v143 a

Covalent organic frameworks (COFs) are ideal host matrices for biomolecule immobilization and biocatalysis due to their high porosity, various functionalities, and structural robustness. However, the porosity of COFs is limited to the micropore dimension, which restricts the immobilization of enzymes with large volumes and obstructs substrate flow during enzyme catalysis. A hierarchical 3D nanostructure possessing micro-, meso-, and macroporosity could be a beneficial host matrix for such enzyme catalysis. In this study, we employed an in situ CO2 gas effervescence technique to induce disordered macropores in the ordered 2D COF nanostructure, synthesizing hierarchical TpAzo COF-foam. The resulting TpAzo foam matrix facilitates the immobilization of multiple enzymes with higher immobilization efficiency (approximately 1.5 to 4-fold) than the COF. The immobilized cellulolytic enzymes, namely beta-glucosidase (BGL), cellobiohydrolase (CBH), and endoglucanase (EG), remain active inside the TpAzo foam. The immobilized BGL exhibited activity in organic solvents and stability at room temperature (25 degrees C). The enzyme-immobilized TpAzo foam exhibited significant activity towards the hydrolysis of p-nitrophenyl-beta-d-glucopyranoside (BGL@TpAzo-foam: K-m and V-max = 23.5 +/- 3.5 mM and 497.7 +/- 28.0 mu M min(-1)) and carboxymethylcellulose (CBH@TpAzo-foam: K-m and V-max = 18.3 +/- 4.0 mg mL(-1) and 85.2 +/- 9.6 mu M min(-1) and EG@TpAzo-foam: K-m and V-max = 13.2 +/- 2.0 mg mL(-1) and 102.2 +/- 7.1 mu M min(-1)). Subsequently, the multi-enzyme immobilized TpAzo foams were utilized to perform a one-pot tandem conversion from carboxymethylcellulose (CMC) to glucose with high recyclability (10 cycles). This work opens up the possibility of synthesizing enzymes immobilized in TpAzo foam for tandem catalysis.

1 aPaul, Satyadip1 aGupta, Mani1 aDey, Kaushik1 aMahato, Ashok, Kumar1 aBag, Saikat1 aTorris, Arun1 aGowd, Bhoje1 aSajid, Hasnain1 aAddicoat, Matthew, A.1 aDatta, Supratim1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/hierarchical-covalent-organic-framework-foam-multi-enzyme-tandem-catalysis