01783nas a2200229 4500008004100000245009500041210006900136260000800205300001700213490000800230520100100238100001801239700001701257700002201274700001701296700002201313700002801335700001901363700002401382700002001406856012701426 2018 eng d00aInterlayer hydrogen-bonded covalent organic frameworks as high-performance supercapacitors0 aInterlayer hydrogenbonded covalent organic frameworks as highper cSEP a 10941-109450 v1403 aCovalent organic frameworks (COFs) have emerged as promising electrode materials in supercapacitors (SCs). However, their insoluble powder-like nature, poor capacitive performance in pristine form, integrated with inferior electrochemical stability is a primary concern for their long-term use in electrochemical devices. Keeping this in perspective, herein we report a redox active and hydrogen bonded COF with ultrahigh stability in conc. H2SO4 (18 M), conc. HCl (12 M) and NaOH (9 M). The as-synthesized COF fabricated as thin sheets were efficiently employed as a free-standing supercapacitor electrode material using 3 M aq. H2SO4 as an electrolyte. Moreover, the pristine COF sheet showcased outstanding areal capacitance 1600 mF cm(-2) (gravimetric 169 F g(-1)) and excellent cyclic stability (>100 000) without compromising its capacitive performance or Coulombic efficiency. Moreover, as a proof-of-concept, a solid-state supercapacitor device was also assembled and subsequently tested.1 aHalder, Arjun1 aGhosh, Meena1 aKhayum, Abdul, M.1 aBera, Saibal1 aAddicoat, Matthew1 aSasmal, Himadri, Sekhar1 aKarak, Suvendu1 aKurungot, Sreekumar1 aBanerjee, Rahul uhttps://library.ncl.res.in/content/interlayer-hydrogen-bonded-covalent-organic-frameworks-high-performance-supercapacitors01713nas a2200229 4500008004100000245012500041210006900166260000800235300001400243490000700257520090400264100001801168700001901186700002201205700001701227700002201244700002601266700002101292700001801313700002001331856013201351 2018 eng d00aUltrastable imine-based covalent organic frameworks for sulfuric acid recovery: an effect of interlayer hydrogen bonding0 aUltrastable iminebased covalent organic frameworks for sulfuric  cMAY a5797-58020 v573 aA rapid and scalable synthesis of six new imine-linked highly porous and crystalline COFs is presented that feature exceptionally high chemical stability in harsh environments including conc. H2SO4 (18M), conc. HCl (12M), and NaOH (9M). This is because of the presence of strong interlayer C-H center dot center dot center dot N hydrogen bonding among the individual layers, which provides significant steric hindrance and a hydrophobic environment around the imine (-C=N-) bonds, thus preventing their hydrolysis in such an abrasive environment. These COFs were further converted into porous, crystalline, self-standing, and crack-free COF membranes (COFMs) with extremely high chemical stability for their potential applications for sulfuric acid recovery. The as-synthesized COFMs exhibit unprecedented permeance for acetonitrile (280 Lm(-2) h(-1) bar(-1)) and acetone (260 Lm(-2) h(-1) bar(-1)).1 aHalder, Arjun1 aKarak, Suvendu1 aAddicoat, Matthew1 aBera, Saibal1 aChakraborty, Amit1 aKunjattu, Shebeeb, H.1 aPachfule, Pradip1 aHeine, Thomas1 aBanerjee, Rahul uhttps://library.ncl.res.in/content/ultrastable-imine-based-covalent-organic-frameworks-sulfuric-acid-recovery-effect-interlayer02417nas a2200289 4500008004100000022001400041245009500055210006900150260000800219300001400227490000700241520151000248653002301758653001501781653001801796653001701814653002301831100001701854700001701871700001901888700001801907700001901925700001901944700002201963700002001985856012202005 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 uhttps://library.ncl.res.in/content/porosity-switching-polymorphic-porous-organic-cages-exceptional-chemical-stability01493nas a2200205 4500008004100000022001400041245011700055210006900172260000900241300001400250490000800264520075900272100002101031700002401052700002101076700002201097700002501119700002001144856012301164 2019 eng d a0002-786300aTriazine functionalized porous covalent organic framework for photo-organocatalytic E-Z isomerization of olefins0 aTriazine functionalized porous covalent organic framework for ph cAPR  a6152-61560 v1413 a

Visible light-mediated photocatalytic organic transformation has drawn significant attention as an alternative process for replacing thermal reactions. Although precious metal/organic dyes based homogeneous photocatalysts have been developed, their toxic and nonreusable nature makes them inappropriate for large-scale production. Therefore, we have synthesized a triazine and a keto functionalized nonmetal based covalent organic framework (TpTt) for heterogeneous photo catalysis. As the catalyst shows significant absorption of visible light, it has been applied for the photocatalytic uphill conversion of trans-stilbene to cis-stilbene in the presence of blue light-emitting diodes with broad substrate scope via an energy transfer process.

1 aBhadra, Mohitosh1 aKandambeth, Sharath1 aSahoo, Manoj, K.1 aAddicoat, Matthew1 aBalaraman, Ekambaram1 aBanerjee, Rahul uhttps://library.ncl.res.in/content/triazine-functionalized-porous-covalent-organic-framework-photo-organocatalytic-e-z06517nas a2200205 4500008004100000245012300041210006900164260000800233490000700241520576600248100002806014700002706042700001806069700001706087700002206104700001906126700002406145700002006169856012206189 2019 eng d00aWeak intermolecular interactions in covalent organic framework-carbon nanofiber based crystalline yet flexible devices0 aWeak intermolecular interactions in covalent organic frameworkca cAUG0 v113 a

The redox-active and porous structural backbone of covalent organic frameworks (COFs) can facilitate high-performance electrochemical energy storage devices. However, the utilities of such 2D materials as supercapacitor electrodes in advanced self-charging power-pack systems have been obstructed due to the poor electrical conductivity and subsequent indigent performance. Herein, we report an effective strategy to enhance the electrical conductivity of COF thin sheets through the in situ solid-state inclusion of carbon nanofibers (CNF) into the COF precursor matrix. The obtained COF-CNF hybrids possess a significant intermolecular π···π interaction between COF and the graphene layers of the CNF. As a result, these COF-CNF hybrids (DqTp-CNF and DqDaTp-CNF) exhibit good electrical conductivity (0.25 × 10–3 S cm–1), as well as high performance in electrochemical energy storage (DqTp-CNF: 464 mF cm–2 at 0.25 mA cm–2). Also, the fabricated, mechanically strong quasi-solid-state supercapacitor (DqDaTp-CNF SC) delivered an ultrahigh device capacitance of 167 mF cm–2 at 0.5 mA cm–2. Furthermore, we integrated a monolithic photovoltaic self-charging power pack by assembling DqDaTp-CNF SC with a perovskite solar cell. The fabricated self-charging power pack delivered excellent performance in the areal capacitance (42 mF cm–2) at 0.25 mA cm–2 after photocharging for 300 s.

1 aMohammed, Abdul, Khayum1 aVijayakumar, Vidyanand1 aHalder, Arjun1 aGhosh, Meena1 aAddicoat, Matthew1 aBansode, Umesh1 aKurungot, Sreekumar1 aBanerjee, Rahul uhttps://library.ncl.res.in/content/weak-intermolecular-interactions-covalent-organic-framework-carbon-nanofiber-based06784nas a2200205 4500008004100000245010500041210006900146260000800215520603400223100002806257700001706285700002706302700001806329700002006347700001806367700002206385700002406407700002006431856012706451 2019 eng d00aZinc ion interactions in a two-dimensional covalent organic framework based aqueous zinc ion battery0 aZinc ion interactions in a twodimensional covalent organic frame cAUG3 a

The two-dimensional structural features of covalent organic frameworks (COFs) can promote the electrochemical storage of cations like H+, Li+, and Na+ through both faradaic and non-faradaic processes. However, the electrochemical storage of cations like Zn2+ ion is still unexplored although it bears a promising divalent charge. Herein, for the first time, we have utilized hydroquinone linked β-ketoenamine COF acting as a Zn2+ anchor in an aqueous rechargeable zinc ion battery. The charge-storage mechanism comprises of an efficient reversible interlayer interaction of Zn2+ ions with the functional moieties in the adjacent layers of COF (−182.0 kcal mol−1). Notably, due to the well-defined nanopores and structural organization, a constructed full cell, displays a discharge capacity as high as 276 mA h g−1 at a current rate of 125 mA g−1.

1 aMohammed, Abdul, Khayum1 aGhosh, Meena1 aVijayakumar, Vidyanand1 aHalder, Arjun1 aNurhuda, Maryam1 aKumar, Sushil1 aAddicoat, Matthew1 aKurungot, Sreekumar1 aBanerjee, Rahul uhttps://library.ncl.res.in/content/zinc-ion-interactions-two-dimensional-covalent-organic-framework-based-aqueous-zinc-ion02436nas a2200241 4500008004100000022001400041245015800055210006900213260000900282300001400291490000800305520154300313100002801856700002301884700002701907700001901934700001801953700002201971700002201993700003202015700002002047856012702067 2020 eng d a0002-786300aConnecting microscopic structures, mesoscale assemblies, and macroscopic architectures in 3D-printed hierarchical porous covalent organic framework foams0 aConnecting microscopic structures mesoscale assemblies and macro cMAY  a8252-82610 v1423 a

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.

1 aMohammed, Abdul, Khayum1 aUsgaonkar, Saurabh1 aKanheerampockil, Fayis1 aKarak, Suvendu1 aHalder, Arjun1 aTharkar, Minakshi1 aAddicoat, Matthew1 aAjithkumar, Thalasseril, G.1 aBanerjee, Rahul uhttps://library.ncl.res.in/content/connecting-microscopic-structures-mesoscale-assemblies-and-macroscopic-architectures-3d01808nas a2200253 4500008004100000022001400041245008800055210006900143260000900212300001600221490000700237520096600244653001901210653002501229653003801254653002601292653001801318100001901336700002001355700001701375700002201392700002001414856012001434 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 uhttps://library.ncl.res.in/content/morphological-evolution-two-dimensional-porous-hexagonal-trimesic-acid-framework