@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: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 {46375, title = {Tandem catalysis by in-situ generated microporous COF-Pd nanoparticle hybrids}, journal = {Acta Crystallographica A-Foundation and Advances}, volume = {70}, year = {2014}, month = {MAR}, pages = {C1034}, type = {Meeting Abstract}, keywords = {covalent organic frameworks, Pd nanoparticles, tandem catalysis}, issn = {2053-2733}, author = {Bhadra, Mohitosh 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 {46326, title = {Ag nanoparticles supported on a resorcinol-phenylenediamine-based covalent organic framework for chemical fixation of CO2}, journal = {Chemistry-An Asian Journal }, year = {2019}, month = {OCT}, type = {Article; Early Access}, abstract = {

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

}, keywords = {CO2 capture, covalent organic frameworks, cyclic carbonates, Propargyl alcohols, silver nanoparticles}, issn = {1861-4728}, doi = {10.1002/asia.201901157}, author = {Chakraborty, Debanjan and Shekhar, Pragalbh and Singh, Himan Dev and Kushwaha, Rinku and Vinod, C. P. and Vaidhyanathan, Ramanathan} } @article {47158, title = {Nanoparticle size-fractionation through self-standing porous covalent organic framework films}, journal = {Angewandte Chemie-International Edition}, volume = {59}, year = {2020}, month = {JAN}, pages = {1161-1165}, type = {Article}, abstract = {

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.

}, keywords = {covalent organic frameworks, films, nanofilter, Nanoparticles, size-selective separation}, issn = {1433-7851}, doi = {10.1002/anie.201912381, Early Access Date = DEC 2019}, author = {Dey, Kaushik and Kunjattu, Shebeeb H. and Chahande, Anurag M. and Banerjee, Rahul} } @article {47067, title = {Exceptional capacitance enhancement of a non-conducting COF through potential-driven chemical modulation by redox electrolyte}, journal = {Advanced Energy Materials}, volume = {11}, year = {2021}, month = {APR}, pages = {2003626}, type = {Article}, abstract = {

Capacitors are the most practical high-storage and rapid charge-release devices. The number of ions stored per unit area and their interaction strength with the electrode dictates capacitor-performance. Microporous materials provide a high storage surface and optimal interactions. Adsorbing electron-rich and easily polarizable molecules into microporous electrodes is expected to boost Faradaic pseudo-activity. If such electrode-electrolyte interactions can be made as a potential-driven reversible process, the resulting capacitors would be adaptable and device-friendly. A composite covalent organic framework (COF)-carbon electrode with redox-active KI is combined in an H2SO4 electrolyte for the first time. This composite electrode benefits from the redox-functionality of COF and electronic conductivity of carbon, leading to superior capacitative activity. Operando spectro-electrochemical measurements reveal the existence of multiple polyiodide species, although the I-3(-) is the predominantly electroactive species adsorbing on the microporous triazine-phenol COF electrode. A systematic fabrication of the flexible solid-state devices using the COF-redox-electrolyte reveals a high areal capacitance of 270 +/- 11 mF cm(-2) and gravimetric capacitance of 57 +/- 8 F g(-1). The inclusion of KI in H2SO4 (electrolyte) yields an approximately eight-fold enhancement in solid-state gravimetric specific capacitance. The imine-COF retains 89\% of its capacity even after 10 000 cycles.

}, keywords = {covalent organic frameworks, polyiodide, redox electrolytes, solid\&\#8208, state capacitors, Supercapacitors}, issn = {1614-6832}, doi = {10.1002/aenm.202003626, Early Access Date = FEB 2021}, author = {Kushwaha, Rinku and Haldar, Sattwick and Shekhar, Pragalbh and Krishnan, Akshara and Saha, Jayeeta and Hui, Pramiti and Vinod, Chathakudath Prabhakaran and Subramaniam, Chandramouli and Vaidhyanathan, Ramanathan} } @article {48335, title = {2D layered nanomaterials as fillers in polymer composite electrolytes for lithium batteries}, journal = {Advanced Energy Materials}, volume = {13}, year = {2023}, month = {APR}, type = {Review}, abstract = {

Polymer composite electrolytes (PCEs), i.e., materials combining the disciplines of polymer chemistry, inorganic chemistry, and electrochemistry, have received tremendous attention within academia and industry for lithium-based battery applications. While PCEs often comprise 3D micro- or nanoparticles, this review thoroughly summarizes the prospects of 2D layered inorganic, organic, and hybrid nanomaterials as active (ion conductive) or passive (nonion conductive) fillers in PCEs. The synthetic inorganic nanofillers covered here include graphene oxide, boron nitride, transition metal chalcogenides, phosphorene, and MXenes. Furthermore, the use of naturally occurring 2D layered clay minerals, such as layered double hydroxides and silicates, in PCEs is also thoroughly detailed considering their impact on battery cell performance. Despite the dominance of 2D layered inorganic materials, their organic and hybrid counterparts, such as 2D covalent organic frameworks and 2D metal-organic frameworks are also identified as tuneable nanofillers for use in PCE. Hence, this review gives an overview of the plethora of options available for the selective development of both the 2D layered nanofillers and resulting PCEs, which can revolutionize the field of polymer-based solid-state electrolytes and their implementation in lithium and post-lithium batteries.

}, keywords = {2D materials, clay minerals, covalent organic frameworks, metal-organic frameworks, MXene, polymer composite electrolyte, solid-state batteries}, issn = {1614-6832}, doi = {10.1002/aenm.202203326}, author = {Vijayakumar, Vidyanand and Ghosh, Meena and Asokan, Kiran and Sukumaran, Santhosh Babu and Kurungot, Sreekumar and Mindemark, Jonas and Brandell, Daniel and Winter, Martin and Nair, Jijeesh Ravi} } @article {48735, title = {Made to measure squaramide COF cathode for zinc dual-ion battery with enriched storage via redox electrolyte}, journal = {Advanced Energy Materials}, volume = {13}, year = {2023}, month = {SEP}, type = {Article}, abstract = {

Aqueous rechargeable batteries are promising grid-scale energy storage devices because of their affordability, operational safety, and environmental benignity. Among these, Zn-ion batteries (ZIBs) have unfolded new horizons. Designing superior cathodes for ZIBs is crucial. Covalent organic frameworks (COFs) can be made redox active with a high storage surface. Here, for the first time, a chelating COF with redox-active ZnI2 in a ZnSO4(aq) electrolyte is combined. Including iodide harvests an approximately threefold enhancement in capacity from 208 to 690 mAh g(-1) at 1.5 A g(-1), the highest among all the COF-derived ZIBs. Remarkably, a charge-discharge curve at 1.3 V exhibits very limited dropout voltage and super-flat platform, with a remarkable capacity of 600 mAh g(-1) at 5 A g(-1) stable up to 6000 cycles, confirming that the polyiodide generation and storage are sustainable. The COF{\textquoteright}s dual-ion storage (Zn2+ and polyidode) delivers a ZIB with the highest energy density. Spectro-electrochemical measurements coupled with X-ray photoelectron spectroscopy unambiguously unveil the existence of multiple polyiodide species, with I-3(-) and IO3- ions as the prominent species. The latter gets reduced at the COF electrode under an applied potential, leaving I-3(-) as the major species stored on the COF. The prospect of COF-polyiodide((aq)) is a windfall for metal-ion batteries.

}, keywords = {covalent organic frameworks, flexible batteries, polyiodide, redox electrolytes, Zn ion batteries}, issn = {1614-6832}, doi = {10.1002/aenm.202301049}, author = {Kushwaha, Rinku and Jain, Chitvan and Shekhar, Pragalbh and Rase, Deepak and Illathvalappil, Rajith and Mekan, Deep and Camellus, Augastus and Vinod, Chathakudath Prabhakaran and Vaidhyanathan, Ramanathan} } @article {48953, title = {Tailoring COFs: transforming nonconducting 2D layered COF into a conducting quasi-3D architecture via interlayer knitting with polypyrrole}, journal = {Journal of the American Chemical Society}, volume = {146}, year = {2023}, month = {DEC}, pages = {487-499}, type = {Journal Article}, abstract = {

Improving the electronic conductivity and the structural robustness of covalent organic frameworks (COFs) is paramount. Here, we covalently cross-link a 2D COF with polypyrrole (Ppy) chains to form a quasi-3D COF. The 3D COF shows well-defined reflections in the SAED patterns distinctly indexed to its modeled crystal structure. This knitting of 2D COF layers with conjugated polypyrrole units improves electronic conductivity from 10(-9) to 10(-2 )S m(-1). This conductivity boost is affirmed by the presence of density of states near the Fermi level in the 3D COF, and this elevates the COF{\textquoteright}s valence band maximum by 0.52 eV with respect to the parent 2D pyrrole-functionalized COF, which agrees well with the opto-electro band gaps. The extent of HOMO elevation suggests the predominant existence of a polaron state (radical cation), giving rise to a strong EPR signal, most likely sourced from the cross-linking polypyrrole chains. A supercapacitor devised with COF20-Ppy records a high areal capacitance of 377.6 mF cm(-2), higher than that of the COF loaded with noncovalently linked polypyrrole chains. Thus, the polypyrrole acts as a {\textquoteleft}{\textquoteleft}conjugation bridge{\textquoteright}{\textquoteright} across the layers, lowering the band gap and providing polarons and additional conduction pathways. This marks a far-reaching approach to converting many 2D COFs into highly ordered and conducting 3D ones.

}, keywords = {covalent organic frameworks, Electrical conductivity}, issn = {0002-7863}, doi = {10.1021/jacs.3c09937}, author = {Jain, Chitvan and Kushwaha, Rinku and Rase, Deepak and Shekhar, Pragalbh and Shelke, Ankita and Sonwani, Disha and Ajithkumar, Thalasseril G. and Vinod, Chathakudath Prabhakaran and Vaidhyanathan, Ramanathan} }