@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:000327410300055, title = {Enhancement of chemical stability and crystallinity in porphyrin-containing covalent organic frameworks by intramolecular hydrogen bonds}, journal = {Angewandte Chemie-International Edition}, volume = {52}, number = {49}, year = {2013}, month = {DEC}, pages = {13052-13056}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, keywords = {covalent organic frameworks, hydrogen bonds, mesoporous materials, porphyrinoids, tautomerism}, issn = {1433-7851}, doi = {10.1002/anie.201306775}, author = {Kandambeth, Sharath and Shinde, Digambar Balaji and Panda, Manas K. and Lukose, Binit and Heine, Thomas and Banerjee, Rahul} } @article { ISI:000317548400026, title = {Mechanochemical synthesis of chemically stable isoreticular covalent organic frameworks}, journal = {Journal of the American Chemical Society}, volume = {135}, number = {14}, year = {2013}, month = {APR}, pages = {5328-5331}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Three thermally and chemically stable isoreticular covalent organic frameworks (COFs) were synthesized via room-temperature solvent-free mechanochemical grinding. These COFs were successfully compared with their solvothermally synthesized counterparts in all aspects. These solvent-free mechanochemically synthesized COFs have moderate crystallinity with remarkable stability in boiling water, acid (9 N HCl), and base [TpBD (MC) in 3 N NaOH and TpPa-2 (MC) in 9 N NaOH]. Exfoliation of COF layers was simultaneously observed with COF formation during mechanochemical synthesis. The structures thus obtained seemed to have a graphene-like layered morphology (exfoliated layers), unlike the parent COFs synthesized solvothermally.

}, issn = {0002-7863}, doi = {10.1021/ja4017842}, author = {Biswal, Bishnu P. and Chandra, Suman and Kandambeth, Sharath and Lukose, Binit and Heine, Thomas and Banerjeet, Rahul} } @article { ISI:000313263300022, title = {Porous-organic-framework-templated nitrogen-rich porous carbon as a more proficient electrocatalyst than Pt/C for the electrochemical reduction of oxygen}, journal = {Chemistry-A European Journal}, volume = {19}, number = {3}, year = {2013}, month = {JAN}, pages = {974-980}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Porous nitrogen-rich carbon (POF-C-1000) that was synthesized by using a porous organic framework (POF) as a self-sacrificing host template in a nanocasting process possessed a high degree of graphitization in an ordered structural arrangement with large domains and well-ordered arrays of carbon sheets. POF-C-1000 exhibits favorable electrocatalytic activity for the oxygen-reduction reaction (ORR) with a clear positive shift of about 40 mV in the onset potential compared to that of a traditional, commercially available Pt/C catalyst. In addition, irrespective of its moderate surface area (785 m2?g-1), POF-C-1000 showed a reasonable H2 adsorption of 1.6 wt?\% (77 K) and a CO2 uptake of 3.5 mmol?g-1 (273 K).

}, keywords = {Adsorption, Electrochemistry, fuel cells, oxygen-reduction reaction, porous organic frameworks}, issn = {0947-6539}, doi = {10.1002/chem.201202940}, author = {Pachfule, Pradip and Dhavale, Vishal M. and Kandambeth, Sharath and Kurungot, Sreekumar and Banerjee, Rahul} } @article {PACHFULE, title = {Highly stable covalent organic framework-Au nanoparticles hybrids for enhanced activity for nitrophenol reduction}, journal = {Chemical Communications}, volume = {50}, number = {24}, year = {2014}, month = {JAN}, pages = {3169-3172}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

{Gold [

}, issn = {1359-7345}, doi = {10.1039/c3cc49176e}, author = {Pachfule, Pradip and Kandambeth, Sharath and Diaz, David Diaz and Banerjee, Rahul} } @article { ISI:000342990400003, title = {Mechanosynthesis of imine, beta-ketoenamine, and hydrogen-bonded imine-linked covalent organic frameworks using liquid-assisted grinding}, journal = {Chemical Communications}, volume = {50}, number = {84}, year = {2014}, month = {JUL}, pages = {12615-12618}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A variety of aromatic amines/hydrazides and aldehydes have been utilized for the construction of crystalline COFs at a faster rate and in high yield, irrespective of their reactivity and solubility using the Liquid-Assisted Grinding (LAG) method.

}, issn = {1359-7345}, doi = {10.1039/c4cc03389b}, author = {Das, Gobinda and Shinde, Digambar Balaji and Kandambeth, Sharath and Biswal, Bishnu P. and Banerjee, Rahul} } @article { ISI:000335924100043, title = {Multifunctional and robust covalent organic framework-nanoparticle hybrids}, journal = {Journal of Materials Chemistry A}, volume = {2}, number = {21}, year = {2014}, month = {MAR}, pages = {7944-7952}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Highly dispersed Pd(0) nanoparticles were successfully immobilized into a stable, crystalline and porous covalent organic framework (COF), TpPa-1, by a solution infiltration method using NABH(4) as a reducing agent. High resolution and dark field TEM images confirmed the uniform loading of the Pd(0) nanoparticles into the TpPa-1 matrix without aggregation. This hybrid material exhibited excellent catalytic activity towards the Cu free Sonogashira, Heck and sequential one pot Heck-Sonogashira cross-coupling reactions under basic conditions, and with superior performance compared to commercially available Pd supported on activated charcoal (i.e., 1, 5 and 10 wt\%). Additionally, the precursor Pd(II)-doped COF also displayed competitive catalytic activity for the intramolecular oxidative biaryl synthesis under acidic conditions. Both catalysts were found to be highly stable under the reaction conditions showing negligible metal leaching, non-sintering behavior, and good recyclability. To the best of our knowledge, the organic support used in this work, TpPa-1, constitutes the first COF matrix that can hold both Pd(0) nanoparticles and Pd(II) complex without aggregation for catalytic purposes under both highly acidic and basic conditions.

}, issn = {2050-7488}, doi = {10.1039/c4ta00284a}, author = {Pachfule, Pradip and Panda, Manas K. and Kandambeth, Sharath and Shivaprasad, S. M. and Diaz, David Diaz and Banerjee, Rahul} } @article { ISI:000335720200011, title = {Phosphoric acid loaded azo (-N=N-) based covalent organic framework for proton conduction}, journal = {Journal of the American Chemical Society}, volume = {136}, number = {18}, year = {2014}, month = {MAY}, pages = {6570-6573}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Two new chemically stable functional crystalline covalent organic frameworkds (COFs) (Tp-Azo and Tp-Stb) were synthesized using the Schiff base reaction between triformylphloroglucinol (Tp) and 4,4{\textquoteright}-azodianiline (Azo) or 4,4{\textquoteright}-diaminostilbene (Stb), respectively. Both COFs show the expected keto-enamine form, and high stability toward boiling water, strong acidic, and basic media. H3PO4 doping in Tp-Azo leads to immobilization of the acid within the porous framework, which facilitates proton conduction in both the hydrous (sigma = 9.9 X 10(-4) S cm(-1)) and anhydrous state (sigma = 6.7 X 10(-5) S cm-1). This report constitutes the first emergence of COFs as proton conducting materials.

}, issn = {0002-7863}, doi = {10.1021/ja502212v}, author = {Chandra, Suman and Kundu, Tanay and Kandambeth, Sharath and BabaRao, Ravichandar and Marathe, Yogesh N. and Kunjir, Shrikant M. and Banerjee, Rahul} } @article { ISI:000345975000014, title = {Bifunctional covalent organic frameworks with two dimensional organocatalytic micropores}, journal = {Chemical Communications}, volume = {51}, number = {2}, year = {2015}, month = {NOV}, pages = {310-313}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

We report the successful incorporation of bifunctional (acid/base) catalytic sites in the crystalline organocatalytic porous COF (2,3-DhaTph). Due to the presence of acidic (catachol) and basic (porphyrin) sites, 2,3-DhaTph shows significant selectivity, reusability, and excellent ability to perform the cascade reaction.

}, issn = {1359-7345}, doi = {10.1039/c4cc07104b}, author = {Shinde, Digambar Balaji and Kandambeth, Sharath and Pachfule, Pradip and Kumar, Raya Rahul 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 { ISI:000365205000004, title = {Pore surface engineering in porous, chemically stable covalent organic frameworks for water adsorption}, journal = {Journal of Materials Chemistry A}, volume = {3}, number = {47}, year = {2015}, month = {NOV}, pages = {23664-23669}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Herein, we have explored the possibility of a class of covalent organic frameworks (COFs) as water adsorbing materials. We have selected, synthesized 12 chemically stable functionalized Schiff base COFs and thoroughly studied their water uptake behaviour. Further, a deep understanding was developed with these COFs towards the effects of condensation pressure of water and hydrophilic/hydrophobic groups present in the COF pores on water absorption capacity and ultimately, their recyclability. Among all reported COFs, TpPa-1 shows the highest water uptake of 30 wt\% (368 cm(3) g(-1); 17 mmol g(-1)) at P/P-0 = 0.3, which is also comparable with the recently reported carbon materials and few well known MOFs. This study also reveals that the overall water uptake of COFs can be tuned systematically based on chemical functionality and pore size in a wider window of relative pressures.

}, issn = {2050-7488}, doi = {10.1039/c5ta07998e}, author = {Biswal, Bishnu P. and Kandambeth, Sharath and Chandra, Suman and Shinde, Digambar Balaji and Bera, Saibal and Karak, Suvendu and Garai, Bikash and Kharul, Ulhas K. and Banerjee, Rahul} } @article { ISI:000353702500026, title = {Self-templated chemically stable hollow spherical covalent organic framework}, journal = {Nature Communications}, volume = {6}, year = {2015}, month = {APR}, pages = {6786}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {

Covalent organic frameworks are a family of crystalline porous materials with promising applications. Although active research on the design and synthesis of covalent organic frameworks has been ongoing for almost a decade, the mechanisms of formation of covalent organic frameworks crystallites remain poorly understood. Here we report the synthesis of a hollow spherical covalent organic framework with mesoporous walls in a single-step template-free method. A detailed time-dependent study of hollow sphere formation reveals that an inside-out Ostwald ripening process is responsible for the hollow sphere formation. The synthesized covalent organic framework hollow spheres are highly porous (surface area similar to 1,500m(2) g(-1)), crystalline and chemically stable, due to the presence of strong intramolecular hydrogen bonding. These mesoporous hollow sphere covalent organic frameworks are used for a trypsin immobilization study, which shows an uptake of 15.5 mu mol g(-1) of trypsin.

}, issn = {2041-1723}, doi = {10.1038/ncomms7786}, author = {Kandambeth, Sharath and Venkatesh, V. and Shinde, Digambar B. and Kumari, Sushma and Halder, Arjun 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 {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 {43030, title = {Decoding the morphological diversity in two dimensional crystalline porous polymers by core planarity modulation}, journal = {Angewandte Chemie - International Edition}, volume = {55}, year = {2016}, month = {JUN}, pages = {7806-7810}, doi = {10.1002/anie.201600087}, author = {Halder, Arjun and Kandambeth, Sharath and Biswal, Bishnu P. and Kaur, Gagandeep and Roy, Neha Chaki and Addicoat, Matthew A. and Salunke, Jagadish K. and Banerjee, Subhrashis and Vanka, Kumar and Heine, Thomas and Verma, Sandeep and Banerjee, Rahul} } @article { ISI:000369665800035, title = {Mechanochemically synthesized covalent organic framework as a proton-conducting solid electrolyte}, journal = {Journal of Materials Chemistry A}, volume = {4}, number = {7}, year = {2016}, month = {JAN}, pages = {2682-2690}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Mechanochemistry has become an increasingly important synthetic tool for a waste-free environment. However, the poor quality of the so-derived materials in terms of their crystallinity and porosity has been their major drawback for any practical applications. In this report, we have for the first time successfully leveraged such characteristics to show that the mechanochemically synthesized bipyridine based covalent organic framework (COF) outperforms its conventional solvothermal counterpart as an efficient solid-state electrolyte in PEM fuel cells. Marking the first such attempt in COFs, a Membrane Electrode Assembly (MEA) fabricated using the mechanochemically synthesized COF was observed to inhibit the fuel crossover and build up a stable Open Circuit Voltage (OCV = 0.93 V at 50 degrees C), thereby establishing itself as an effective solid electrolyte material (with a proton conductivity of 1.4 x 10(-2) S cm(-1)), while the solvothermally synthesized COF proved ineffective under similar conditions.

}, issn = {2050-7488}, doi = {10.1039/c5ta10521h}, author = {Shinde, Digambar Balaji and Aiyappa, Harshitha Barike and Bhadra, Mohitosh and Biswal, Bishnu P. and Wadge, Pritish and Kandambeth, Sharath and Garai, Bikash and Kundu, Tanay and Kurungot, Sreekumar and Banerjee, Rahul} } @article {43721, title = {Porous porphyrin organic polymer (PPOP) for visible light triggered hydrogen production}, journal = {Chemical Communications}, volume = {53}, year = {2017}, month = {APR}, pages = {4461-4464}, type = {Article}, chapter = {4461-4464}, abstract = {A visible light active porphyrin-based porous organic polymer having high chemical stability and surface area has been synthesized and its ability to influence the photocatalytic activity of large band gap-TiO2 nanoparticles has been tested. The resultant composite shows improved photocatalytic activity as compared to the parent precursors. This study provides insights into the photosensitizing ability of the polymer in addition to its ability to firmly harbor nanoparticles onto its surface.}, doi = {10.1039/c7cc00879a}, author = {Mukherjee, Gargi and Thote, Jayshri and Aiyappa, Harshitha Barike and Kandambeth, Sharath and Banerjee, Subhrashis and Vanka, Kumar and Banerjee, Rahul} } @article {43732, title = {Predesigned metal-anchored building block for in situ generation of Pd nanoparticles in porous covalent organic framework: application in heterogeneous tandem catalysis}, journal = {ACS Applied Materials \& Interfaces}, volume = {9}, year = {2017}, month = {APR}, pages = {13785-13792}, type = {Article}, abstract = {The development of nanoparticle-polymer-hybrid-based heterogeneous catalysts with high reactivity and good recyclability is highly desired for their applications in the chemical and pharmaceutical industries: Herein, we have developed a novel synthetic strategy by choosing a predesigned metal-anchored building block for in situ generation of metal (Pd) nanoparticles in the stable, porous, and crystalline covalent organic framework (COF), without using conventional reducing agents. In situ generation of Pd nanoparticles in the COF Skeleton is explicitly confirmed{\textquoteright} from PXRD, XPS, TEM images, and N-15 NMR spectral analysis. This hybrid material is found to be an excellent reusable heterogeneous catalyst for the synthesis of biologically and pharmaceutically important 2-substituted benzofurans from 2-bromophencils and terminal alkynes via a tandem process with the turnover number up to 1101. The heterogeneity of the catalytic process is unambiguously verified by a mercury poisoning experiment and leaching test. This hybrid material shows superior catalytic performance compared to commercially available homogeneous as well as heterogeneous Pd catalysts.}, doi = {10.1021/acsami.7b02355}, author = {Bhadra, Mohitosh and Sasmal, Himadri Sekhar and Basu, Arghya and Midya, Siba P. and Kandambeth, Sharath and Pachfule, Pradip and Balaraman, Ekambaram and Banerjee, Rahul} } @article { ISI:000371453700057, title = {Self-exfoliated guanidinium-based ionic covalent organic nanosheets (iCONs)}, journal = {Journal of the American Chemical Society}, volume = {138}, number = {8}, year = {2017}, month = {MAR}, pages = {2823-2828}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Covalent organic nanosheets (CONs) have emerged as functional two-dimensional materials for versatile applications. Although pi-pi stacking between layers, hydrolytic instability, possible restacking prevents their exfoliation on to few thin layered CONs from crystalline porous polymers. We anticipated rational designing of a structure by intrinsic ionic linker could be the solution to produce self-exfoliated CONs without external stimuli. In an attempt to address this issue, we have synthesized three self-exfoliated guanidinium halide based ionic covalent organic nanosheets (iCONs) with antimicrobial property. Self-exfoliation phenomenon has been supported by molecular dynamics (MD) simulation as well. Intrinsic ionic guanidinium unit plays the pivotal role for both self-exfoliation and antibacterial property against both Gram-positive and Gram-negative bacteria. Using such iCONs, we have devised a Mixed matrix membrane which could be useful for antimicrobial coatings with plausible medical benefits.

}, issn = {0002-7863}, doi = {10.1021/jacs.5b13533}, author = {Mitra, Shouvik and Kandambeth, Sharath and Biswal, Bishnu P. and Khayum, Abdul M. and Choudhury, Chandan Kumar and Mehta, Mihir R. and Kaur, Gagandeep and Banerjee, Subhrashis and Prabhune, Asmita and Verma, Sandeep and Roy, Sudip and Kharul, Ulhas K. and Banerjee, Rahul} } @article {43533, title = {Targeted drug delivery in covalent organic nanosheets (CONs) via sequential postsynthetic modification}, journal = {Journal of the American Chemical Society}, volume = {139}, year = {2017}, month = {MAR}, pages = {4513-4520}, abstract = {Covalent organic nanosheets (CONs) have emerged as a new class of functional two-dimensional (2D) porous organic polymeric materials with a high accessible surface, diverse functionality, and chemical stability. They could become versatile candidates for targeted drug delivery. Despite their many advantages, there are limitations to their use for target specific drug delivery. We anticipated that these drawbacks could be overturned by judicious postsynthetic modification steps to use CONs for targeted drug delivery. The postsynthetic modification would not only produce the desired functionality, it would also help to exfoliate to CONs as well. In order to meet this requirement, we have developed a facile, salt-mediated synthesis of covalent organic frameworks (COFs) in the presence of p-toluenesulfonic acid (PTSA). The COFs were subjected to sequential postsynthetic modifications to yield functionalized targeted CONs for targeted delivery of 5-fluorouracil to breast cancer cells. This postsynthetic modification resulted in simultaneous chemical delamination and functionalization to targeted CONs. Targeted CONs showed sustained release of the drug to the cancer cells through receptor mediated endocytosis, which led to cancer cell death via apoptosis. Considering the easy and facile COF synthesis, functionality based postsynthetic modifications, and chemical delamination to CONs for potential advantageous targeted drug delivery, this process can have a significant impact in biomedical applications.}, doi = {10.1021/jacs.7b00925}, author = {Mitra, Shouvik and Sasmal, Himadri Sekhar and Kundu, Tanay and Kandambeth, Sharath and Math, Kavya and Diaz Diaz, David and Banerjee, Rahul} } @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 {46134, title = {Triazine functionalized porous covalent organic framework for photo-organocatalytic E-Z isomerization of olefins}, journal = {Journal of the American Chemical Society}, volume = {141}, year = {2019}, month = {APR }, pages = {6152-6156}, type = {Article}, abstract = {

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.

}, issn = {0002-7863}, doi = {10.1021/jacs.9b01891}, author = {Bhadra, Mohitosh and Kandambeth, Sharath and Sahoo, Manoj K. and Addicoat, Matthew and Balaraman, Ekambaram and Banerjee, Rahul} } @article {48209, title = {Porous covalent organic nanotubes and their assembly in loops and toroids}, journal = {Nature Chemistry}, volume = {14}, year = {2022}, month = {MAY}, pages = {507+}, type = {Article}, abstract = {

Carbon nanotubes, and synthetic organic nanotubes more generally, have in recent decades been widely explored for application in electronic devices, energy storage, catalysis and biosensors. Despite noteworthy progress made in the synthesis of nanotubular architectures with well-defined lengths and diameters, purely covalently bonded organic nanotubes have remained somewhat challenging to prepare. Here we report the synthesis of covalently bonded porous organic nanotubes (CONTs) by Schiff base reaction between a tetratopic amine-functionalized triptycene and a linear dialdehyde. The spatial orientation of the functional groups promotes the growth of the framework in one dimension, and the strong covalent bonds between carbon, nitrogen and oxygen impart the resulting CONTs with high thermal and chemical stability. Upon ultrasonication, the CONTs form intertwined structures that go on to coil and form toroidal superstructures. Computational studies give some insight into the effect of the solvent in this assembly process.

}, issn = {1755-4330}, doi = {10.1038/s41557-022-00908-1}, author = {Koner, Kalipada and Karak, Shayan and Kandambeth, Sharath and Karak, Suvendu and Thomas, Neethu and Leanza, Luigi and Perego, Claudio and Pesce, Luca and Capelli, Riccardo and Moun, Monika and Bhakar, Monika and Ajithkumar, Thalasseril G. and Pavan, Giovanni M. and Banerjee, Rahul} } @article {48416, title = {Viscoelastic covalent organic nanotube fabric via macroscopic entanglement}, journal = {Journal of the American Chemical Society}, volume = {144}, year = {2022}, month = {SEP }, pages = {16052-16059}, type = {Article}, abstract = {

Covalent organic nanotubes (CONTs) are one-dimensional porous frameworks constructed from organic building blocks via dynamic covalent chemistry. CONTs are synthesized as insoluble powder that restricts their potential applications. The judicious selection of 2,2{\textquoteright}-bipyridine-5,5{\textquoteright}-dicarbaldehyde and tetraaminotriptycene as building blocks for TAT-BPy CONTs has led to constructing flexible yet robust and self-standing fabric up to 3 mu m thickness. The TAT-BPy CONTs and TAT-BPy CONT fabric have been characterized by solid-state one-dimensional (1D) C-13 CP-MAS, two-dimensional (2D) C-13-H-1 correlation NMR, 2D H-1-H-1 DQ-SQ NMR, and 2D N-14-H-1 correlation NMR spectroscopy. The mechanism of fabric formation has been established by using high-resolution transmission electron microscopy and scanning electron microscopy techniques. The as-synthesized viscoelastic TAT-BPy CONT fabric exhibits high mechanical strength with a reduced modulus (E-r) of 8 (+/- 3) GPa and hardness (H) of 0.6 (+/- 0.3) GPa. Interestingly, the viscoelastic fabric shows time-dependent elastic depth recovery up to 50-70\%.

}, issn = {0002-7863}, doi = {10.1021/jacs.2c06133}, author = {Koner, Kalipada and Das, Susobhan and Mohata, Shibani and Duong, Nghia Tuan and Nishiyama, Yusuke and Kandambeth, Sharath and Karak, Suvendu and Reddy, C. Malla and Banerjee, Rahul} }