25,428 results match your criteria modification reaction

l-Histidine-Derived Smart Antifouling Biohybrid with Multistimuli Responsivity.

Biomacromolecules 2021 Aug 4. Epub 2021 Aug 4.

Department of Chemistry, Indian Institute of Technology Bhilai, Raipur 492015, Chhattisgarh, India.

A novel dual pH/thermoresponsive amphiphilic poly(histidine methacrylamide)--hydroxyl-terminated polybutadiene--poly(histidine methacrylamide) (PHisMAM--PB--PHisMAM) triblock copolymer biohybrid, composed of hydrophobic PB and ampholytic PHisMAM segments, is developed via direct switching from living anionic polymerization to recyclable nanoparticle catalyst-mediated reversible-deactivation radical polymerization (RDRP). The transformation involved in situ postpolymerization modification of living polybutadiene-based carbanionic species, end-capped with ethylene oxide, into dihydroxyl-terminated polybutadiene and a subsequent reaction with 2-bromo-2-methylpropionyl bromide resulting in a telechelic ATRP macroinitiator (Br-PB-Br). Br-PB-Br was used to mediate RDRP of an l-histidine-derived monomer, HisMAM, yielding a series of PHisMAM--PB--PHisMAM triblock copolymers. Read More

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Chemoselective Copper-Mediated Modification of Selenocysteines in Peptides and Proteins.

J Am Chem Soc 2021 Aug 4. Epub 2021 Aug 4.

Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra, Givat Ram, Jerusalem 9190401, Israel.

Highly valuable bioconjugated molecules must be synthesized through efficient, chemoselective chemical modifications of peptides and proteins. Herein, we report the chemoselective modification of peptides and proteins via a reaction between selenocysteine residues and aryl/alkyl radicals. radical generation from hydrazine substrates and copper ions proceeds rapidly in an aqueous buffer at near neutral pH (5-8), providing a variety of Se-modified linear and cyclic peptides and proteins conjugated to aryl and alkyl molecules, and to affinity label tag (biotin). Read More

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CoSe particles encapsulated in the inner wall of nitrogen-doped carbon matrix nanotubes with rational interfacial bonds for high-performance lithium-ion batteries.

Dalton Trans 2021 Aug 4. Epub 2021 Aug 4.

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.

Cobalt selenides based on the conversion reaction have been widely applied in lithium-ion batteries (LIBs) due to their high conductivity and high specific capacity. However, effectively suppressing the fast capacity fade caused by the irreversible Se/Co dissolution and serious volume change during the cycling process is still a challenge. Herein, a facile and efficient self-generated sacrificial template method is used to prepare Co0. Read More

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Modification of soy protein isolate by Maillard reaction and its application in microencapsulation of Limosilactobacillusreuteri.

J Biosci Bioeng 2021 Jul 31. Epub 2021 Jul 31.

State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, China; College of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, China. Electronic address:

Limosilactobacillusreuteri was encapsulated using Maillard-reaction-products (MRPs) of soy protein isolate (SPI) and α-lactose monohydrate by freeze-drying. The mixed solution of SPI and α-lactose monohydrate was placed in a water bath at 89°C for 160 min for Maillard reaction, and then freeze-dried to obtain MRPs. The effects of Maillard reaction on functional characteristics of MRPs and the properties of MRPs-microcapsules were studied. Read More

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Integrated hand-held electrochemical sensor for multicomponent detection in urine.

Biosens Bioelectron 2021 Jul 27;193:113534. Epub 2021 Jul 27.

Flexible Printed Electronics Technology Center and School of Science, Harbin Institute of Technology, Shenzhen, Guangdong, 518055, China. Electronic address:

Electrochemical sensors have shown great advantage and application potential in point-of-care testing (POCT) related scenarios. However, some fatal problems plague its widespread utilization, which include the susceptibility of sensors to interference in real samples (e.g. Read More

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Jute sticks biomass delignification through laccase-mediator system for enhanced saccharification and sustainable release of fermentable sugar.

Chemosphere 2021 Jul 27;286(Pt 2):131687. Epub 2021 Jul 27.

CSIR-Indian Institute of Petroleum, Mohkampur, Dehradun, 248005, Uttarakhand, India. Electronic address:

Jute sticks obtained after the extraction of jute fiber are an excellent biomass feedstock with a significant amount of carbohydrates that makes it an attractive resource for sustainable energy generation. However, the high lignin content in the jute stick hinders the cellulosic component of the cell wall from enzymatic hydrolysis.This work demonstrates the lignin degradation of jute stick biomass by Trametes maxima laccase in the presence of mediator Hydroxybenzotriazole and improvement in its subsequent saccharification. Read More

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An Advanced 'clickECM' that Can be Modified by the Inverse-Electron Demand Diels-Alder Reaction.

Chembiochem 2021 Aug 3. Epub 2021 Aug 3.

Reutlingen University: Hochschule Reutlingen, School of Applied Chemistry, GERMANY.

The extracellular matrix (ECM) represents the natural environment of the cells in tissue and therefore is a promising biomaterial in a variety of applications. Depending on the purpose it is necessary to equip the ECM with specific addressable functional groups for further modification with bioactive molecules, for controllable cross linking and/or covalent binding to surfaces. Metabolic glycoengineering (MGE) enables the specific modification of the ECM with such functional groups without affecting the native structure of the ECM. Read More

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Rational Design of Highly Stable and Active MXene-Based Bifunctional ORR/OER Double-Atom Catalysts.

Adv Mater 2021 Aug 3:e2102595. Epub 2021 Aug 3.

School of Materials Science and Engineering, Beihang University, Beijing, 100191, P. R. China.

Designing highly active and bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts has attracted great interest toward metal-air batteries. Herein, an efficient solution to the search for MXene-based bifunctional catalysts is proposed by introducing non-noble metals such as Fe/Co/Ni at the surfaces. These results indicate that the ultrahigh activities in Ni1/Ni2- and Fe1/Ni2-modified MXene-based double-atom catalysts (DACs) for bifunctional ORR/OER are better than those of well-known unifunctional catalysts with low overpotentials, such as Pt(111) for the ORR and IrO (110) for the OER. Read More

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Facile Encapsulation of Iridium(III) Complexes in Apoferritin Nanocages as Promising Electrochemiluminescence Nanodots for Immunoassays.

Anal Chem 2021 Aug 3. Epub 2021 Aug 3.

Key Laboratory of Interfacial Reaction & Sensing Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China.

A class of water-soluble electrochemiluminescence (ECL) nanodots were prepared by encapsulating ECL-active iridium complexes into biocompatible horse spleen apoferritin (apoHSF) nanocages for immunoassays. The preparation feasibility was achieved based on the pH-induced disassembly/reassembly nature originated from apoHSF. Two iridium nanodots ( and ) with high ECL efficiency were separately prepared by directing the self-assembly of two water-insoluble luminescent complexes, Ir(ppy) (ppy = 2-phenylpyridine) and Ir(ppy)(acac) (ppy = 2-phenylpyridine and acac = acetylacetonate), in the apoHSF cavity. Read More

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How does the vacancy engineering affect the lignin-derived oxygenates hydrodeoxygenation? Recent advances of vacancy engineering in transition metal sulfide and oxide catalysts.

ChemSusChem 2021 Aug 3. Epub 2021 Aug 3.

Tianjin University, School of Environmental Engineering and Technology, CHINA.

The hydrodeoxygenation (HDO) catalytic conversion of lignin has always been a hot research topic, and vacancy engineering is considered to be a new means to develop more efficient catalysts. Among them, oxygen vacancies and sulfur vacancies are widely used in HDO. Based on the current research status of vacancies in the field of lignin-derived oxygenates, this review discusses in detail the design methods of vacancy engineering, including surface activation, synergistic modification, and morphology control. Read More

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Oxidative deamination of lysine residues by polyphenols generates an equilibrium of aldehyde and 2-piperidinol products.

J Biol Chem 2021 Jul 30:101035. Epub 2021 Jul 30.

Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan; Japan Agency for Medical Research and Development, CREST, Tokyo, Japan. Electronic address:

Polyphenols, especially catechol-type polyphenols, exhibit lysyl oxidase-like activity and mediate oxidative deamination of lysine residues in proteins. Previous studies have shown that polyphenol-mediated oxidative deamination of lysine residues can be associated with altered electrical properties of proteins and increased cross-reactivity with natural IgM antibodies. This interaction suggested that oxidized proteins could act as innate antigens and elicit an innate immune response. Read More

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Low-Level Erbium-Doped Yttrium Aluminum Garnet Laser Irradiation Induced Alteration of Gene Expression in Osteogenic Cells from Rat Calvariae.

Photobiomodul Photomed Laser Surg 2021 Jul 30. Epub 2021 Jul 30.

Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.

The aim of this study was to investigate the effect of low-level erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation on gene expression in osteogenic cells from rat calvariae. Previous studies showed beneficial effects of laser irradiation on bone-related cells. However, few studies have examined the gene expression alteration by laser irradiation on osteogenic cells in a calcified condition. Read More

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Enzyme Catalyzed Copolymerization of Lignosulfonates for Hydrophobic Coatings.

Front Bioeng Biotechnol 2021 14;9:697310. Epub 2021 Jul 14.

Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences, Tulln, Austria.

Enzymatic polymerization of lignin can generate a variety of value-added products concomitantly replacing fossil-based resources. In line with this approach, a laccase from the thermophilic fungus (MtL) was used to couple a hydrophobicity enhancing fluorophenol (FP) molecule, namely 4-[4-(trifluoromethyl)phenoxy]phenol (4,4-F3MPP), as a model substrate onto lignosulfonate (LS). During the coupling reaction changes in fluorescence, phenol content, viscosity and molecular weight (size exclusion chromatography; SEC) were monitored. Read More

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A comprehensive and critical review on key elements to implement enzymatic PET depolymerization for recycling purposes.

Biotechnol Adv 2021 Jul 29:107811. Epub 2021 Jul 29.

Petrobras Research, Development and Innovation Center (Cenpes), Av. Horácio Macedo, n° 950 - Cidade Universitária, Rio de Janeiro, RJ CEP 21941-915, Brazil. Electronic address:

Plastics production and recycling chains must be refitted to a circular economy. Poly(ethylene terephthalate) (PET) is especially suitable for recycling because of its hydrolysable ester bonds and high environmental impact due to employment in single-use packaging, so that recycling processes utilizing enzymes are a promising biotechnological route to monomer recovery. However, enzymatic PET depolymerization still faces challenges to become a competitive route at an industrial level. Read More

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Unprecedented Self-Healing Effect of Li PS Cl-Based All-Solid-State Lithium Battery.

Small 2021 Jul 31:e2101326. Epub 2021 Jul 31.

College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.

Argyrodite Li PS Cl with high Li conductivity is a promising material for solid-state electrolytes (SSEs) in all-solid-state lithium batteries (ASSLBs). However, the narrow electrochemical window of Li PS Cl limits its applications in ASSLBs with high energy densities, and those that consist of high-voltage cathode materials and metallic lithium anodes. Unstable lithium deposition and stripping at interfaces is also a factor that restricts its industrialization. Read More

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Site-specific Umpolung amidation of carboxylic acids via triplet synergistic catalysis.

Nat Commun 2021 07 30;12(1):4637. Epub 2021 Jul 30.

State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.

Development of catalytic amide bond-forming methods is important because they could potentially address the existing limitations of classical methods using superstoichiometric activating reagents. In this paper, we disclose an Umpolung amidation reaction of carboxylic acids with nitroarenes and nitroalkanes enabled by the triplet synergistic catalysis of FeI, P(V)/P(III) and photoredox catalysis, which avoids the production of byproducts from stoichiometric coupling reagents. A wide range of carboxylic acids, including aliphatic, aromatic and alkenyl acids participate smoothly in such reactions, generating structurally diverse amides in good yields (86 examples, up to 97% yield). Read More

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Anti-tumor compounds identification from gossypol Groebke imidazopyridine product.

Bioorg Chem 2021 Jul 5;114:105146. Epub 2021 Jul 5.

Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China. Electronic address:

Series of imidazo[1,2-a]pyridines designed from gossypol modification based on Groebke-Blackburn-Bienaymé reaction were discovered as potent Bcl-2 inhibitors. Compound 4 was found to display good anti-proliferative activities for 7 human cancer cell lines (0.33-1. Read More

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Silinanyl Rhodamines and Silinanyl Fluoresceins for Super-Resolution Microscopy.

J Phys Chem B 2021 Jul 30. Epub 2021 Jul 30.

Central Research Laboratories, Sysmex Corporation, Takatsukadai 4-4-4, Nishi-ku, Kobe, Hyogo 651-2271, Japan.

Single-molecule localization microscopy (SMLM) enables the visualization of biomolecules at unprecedented resolution and requires control of the fluorescent blinking (ON/OFF) states of fluorophores to detect single-molecule fluorescence without overlapping of the signals. Although SMLM probes based on the intramolecular spirocyclization of Si-xanthene fluorophores have been developed, fluorophores with lower ON/OFF ratios are required for SMLM visualization of high-density structures. Here, we describe a silinane structure that lowers the ON/OFF ratio of Si-xanthene fluorophores. Read More

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[Advances of enzymes in the applications of disease treatment and drug preparation].

Sheng Wu Gong Cheng Xue Bao 2021 Jul;37(7):2256-2271

Department of Bioengineering and Biotechnology, College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian, China.

The development of biotechnology and the in-depth research on disease mechanisms have led to increased application of enzymes in the treatment of diseases. In addition, enzymes have shown great potential in drug manufacturing, particularly in production of non-natural organic compounds, due to the advantages of mild reaction conditions, high catalytic efficiency, high specificity, high selectivity and few side reactions. Moreover, the application of genetic engineering, chemical modification of enzymes and immobilization technologies have further improved the function of enzymes. Read More

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Incorporation of backbone modifications in mRNA-displayable peptides.

Methods Enzymol 2021 24;656:521-544. Epub 2021 Jun 24.

Department of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo, Japan. Electronic address:

Here we comprehensively summarize the most recent efforts in our research team, aiming at installing N-methyl and azole backbones into peptides expressed in translation. The genetic code reprogramming using the Flexible In-vitro Translation system (FIT system) has proven to be the most reliable and versatile approach for ribosomally installing various exotic amino acids. However, it had been yet difficult in translating diverse kinds of multiple and consecutive sequences of N-methyl amino acids (AAs). Read More

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Site-Specific Scissors Based on Myeloperoxidase for Phosphorothioate DNA.

J Am Chem Soc 2021 Jul 29. Epub 2021 Jul 29.

Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China.

The tool box of site-specific cleavage for nucleic acid has been an increasingly attractive subject. Especially, the recent emergence of the orthogonally activatable DNA device is closely related to the site-specific scission. However, most of these cleavage strategies are based on exogenous assistance, such as laser irradiation. Read More

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Four component Passerini polymerization of bulky monomers under high shear flow.

Chem Commun (Camb) 2021 Jul 29. Epub 2021 Jul 29.

Centre for Materials Science, School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia.

We introduce a four component Passerini polymerization utilizing sterically bulky isocyanide monomers. Under typical Passerini conditions, bulky isocyanides do not react within standard Passerini reaction timescales (hours). We overcome this challenge via the unique physiochemical conditions present in a vortex fluidic device, reducing the reaction time to 2 h on average. Read More

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Engineering single-atomic ruthenium catalytic sites on defective nickel-iron layered double hydroxide for overall water splitting.

Nat Commun 2021 Jul 28;12(1):4587. Epub 2021 Jul 28.

State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, China.

Rational design of single atom catalyst is critical for efficient sustainable energy conversion. However, the atomic-level control of active sites is essential for electrocatalytic materials in alkaline electrolyte. Moreover, well-defined surface structures lead to in-depth understanding of catalytic mechanisms. Read More

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Programmable DNA Circuits for Flexible and Robust Exciton-Plasmon Interaction-Based Photoelectrochemical Biosensing.

Anal Chem 2021 Jul 28. Epub 2021 Jul 28.

School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng 224051, P. R. China.

DNA circuits as one of the dynamic nanostructures can be rationally designed and show amazing geometrical complexity and nanoscale accuracy, which are becoming increasingly attractive for DNA entropy-driven amplifier design. Herein, a novel and elegant exciton-plasmon interaction (EPI)-based photoelectrochemical (PEC) biosensor was developed with the assistance of a programmable entropy-driven DNA amplifier and superparamagnetic nanostructures. Low-abundance miRNA-let-7a as a model can efficiently initiate the operation of the entropy-driven DNA amplifier, and the released output DNAs can open the partially hybridized double-stranded DNA anchored on [email protected] particles. Read More

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Emerging Cocatalysts on g-C N for Photocatalytic Hydrogen Evolution.

Small 2021 Jul 28:e2101070. Epub 2021 Jul 28.

Shanghai Engineering Research Center for Multi-Media Environmental Catalysis and Resource Utilization, Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai, 200237, China.

Over the past few decades, graphitic carbon nitride (g-C N ) has arisen much attention as a promising candidate for photocatalytic hydrogen evolution reaction (HER) owing to its low cost and visible light response ability. However, the unsatisfied HER performance originated from the strong charge recombination of g-C N severely inhibits the further large-scale application of g-C N . In this case, the utilization of cocatalysts is a novel frontline in the g-C N -based photocatalytic systems due to the positive effects of cocatalysts on supressing charge carrier recombination, reducing the HER overpotential, and improving photocatalytic activity. Read More

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An expedient route to tricyanovinylindoles and indolylmaleimides from -alkynylanilines utilising DMSO as a one-carbon synthon.

Org Biomol Chem 2021 Jul 27. Epub 2021 Jul 27.

Department of Chemistry, Indian Institute of Technology Guwahati, 781039, Assam, India.

A Pd(ii)/Cu(ii) catalysed domino synthesis of tricyanovinylindoles has been achieved using DMSO as a one-carbon synthon. The reaction proceeds via the construction of 2-aryl-3-formyl indole followed by sequential addition of malononitrile and a CN resulting in two C-C, one C[double bond, length as m-dash]C and one C-N bonds in the final product. Furthermore, post-synthetic modification results in the unprecedented formation of 4-cyano-3-indolylmaleimides. Read More

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Structural and spectroscopic characterization of a new series of BaREGeO (RE = Pr, Nd, Gd, and Dy) and BaGdEuGeO tetragermanates.

Dalton Trans 2021 Jul 27. Epub 2021 Jul 27.

Institute of Solid State Chemistry, UB RAS, 620990 Ekaterinburg, Russia.

A new series of Ba2RE2Ge4O13 (RE = Pr, Nd, Gd, Dy) germanates and Ba2Gd2-xEuxGe4O13 (x = 0.1-0.8) solid solutions have been synthesized using the solid-state reaction technique and characterized by X-ray powder diffraction. Read More

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Structural characteristics and improved in vitro hepatoprotective activities of Maillard reaction products of decapeptide IVTNWDDMEK and ribose.

J Food Sci 2021 Jul 27. Epub 2021 Jul 27.

School of Food Science and Technology, Dalian Polytechnic University, Dalian, P.R. China.

Here, a novel decapeptide IVTNWDDMEK with Maillard reactivity derived from scallop Chlamys farreri mantle was identified. The structural characteristics and in vitro hepatoprotective effects of IVTNWDDMEK conjugated with ribose were further investigated. The changes in decapeptide structures were determined by ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR), and atomic force microscopy (AFM), and the modification sites induced by Maillard reaction of IVTNWDDMEK and ribose were monitored by high performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS). Read More

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A hypothesis: Fructosamine-3-Kinase-Related-Protein (FN3KRP) catalyzes deglycation of Maillard intermediates directly downstream from fructosamines.

Rejuvenation Res 2021 Jul 27. Epub 2021 Jul 27.

SeroClear, Research, Englewood, New Jersey, United States;

Non-enzymatic glycation (a.k.a. Read More

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Introducing High Density of Very Active Sites and Stepwise Postmodification for Tailoring the Porosity of Highly Demanding Cr-Based Metal-Organic Frameworks.

Inorg Chem 2021 Jul 27. Epub 2021 Jul 27.

Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications, Jinan University, Guangzhou 510632, China.

Chromium(III)-based metal-organic frameworks (Cr-MOFs) are highly robust and porous and have been very attractive in a wide range of investigations. However, the harsh direct synthetic conditions not only impede the synthesis of new Cr-MOFs but also restrict the introduction of functional groups into them. Postsynthetic modification has somewhat alleviated such difficulties; nevertheless, it still suffered from procedures that are tedious and conditions that are not mild, which often result in low concentration of the functional groups introduced. Read More

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