Query: Chemistry

Candidate papers:

abstract: Ultrathin two dimensional nanosheets of layered transition metal dichalcogenides (TMDs) are fundamentally and technologically intriguing. In contrast to the graphene sheet, they are chemically versatile. Mono or few layered TMDs obtained either through exfoliation of bulk materials or bottom up syntheses are direct gap semiconductors whose bandgap energy, as well as carrier type (n or p type) varies between compounds depending on their composition, structure and dimensionality. In this Review, we describe how the tunable electronic structure of TMDs makes them attractive for a variety of applications. They have been investigated as chemically active electrocatalysts for hydrogen evolution and hydrosulfurization, as well as electrically active materials in opto electronics. Their morphologies and properties are also useful for energy storage applications such as electrodes for Li ion batteries and supercapacitors.
author_names: Manish Chhowalla

Hyeon Suk Shin

Goki Eda

Lain-Jong Li

Kian Ping Loh

Hua Zhang
title: The chemistry of two dimensional layered transition metal dichalcogenide nanosheets.
venue: Nature chemistry
year: 2013

abstract: Supervised learning on molecules has incredible potential to be useful in chemistry, drug discovery, and materials science. Luckily, several promising and closely related neural network models invariant to molecular symmetries have already been described in the literature. These models learn a message passing algorithm and aggregation procedure to compute a function of their entire input graph. At this point, the next step is to find a particularly effective variant of this general approach and apply it to chemical prediction benchmarks until we either solve them or reach the limits of the approach. In this paper, we reformulate existing models into a single common framework we call Message Passing Neural Networks (MPNNs) and explore additional novel variations within this framework. Using MPNNs we demonstrate state of the art results on an important molecular property prediction benchmark; these results are strong enough that we believe future work should focus on datasets with larger molecules or more accurate ground truth labels.
author_names: Justin Gilmer

Samuel S Schoenholz

Patrick F Riley

Oriol Vinyals

George E Dahl
title: Neural Message Passing for Quantum Chemistry
venue: ICML
year: 2017

author_names: John R Rumble
title: CRC Handbook of Chemistry and Physics
year: 2019

abstract: Background Metal organic frameworks (MOFs) are made by linking inorganic and organic units by strong bonds (reticular synthesis) The flexibility with which the constituents' geometry, size, and functionality can be varied has led to more than 20,000 different MOFs being reported and studied within the past decade. The organic units are ditopic or polytopic organic carboxylates (and other similar negatively charged molecules) which, when linked to metal containing units, yield architecturally robust crystalline MOF structures with a typical porosity of greater than 50% of the MOF crystal volume. The surface area values of such MOFs typically range from 1000 to 10,000 m2/g, thus exceeding those of traditional porous materials such as zeolites and carbons. To date, MOFs with permanent porosity are more extensive in their variety and multiplicity than any other class of porous materials. These aspects have made MOFs ideal candidates for storage of fuels (hydrogen and methane) capture of carbon dioxide, and catalysis applications, to mention a few. Metal organic framework (MOF) structures are amenable to expansion and incorporation of multiple functional groups within their interiors. (A) The isoreticular expansion of MOFs maintains the network's topology by using an expanded version of the parent organic linker. Examples of catalysis in MOFs are shown in the large space created by IRMOF 74 XI; Me is a methyl group. (B) Conceptual illustration of a multivariate MOF (MTV MOF) whose pores are decorated by heterogeneous mixtures of functionalities that arrange in specific sequences. (Background) Optical image of zeolitic imidazolate framework (ZIF) crystals. Advances The ability to vary the size and nature of MOF structures without changing their underlying topology gave rise to the isoreticular principle and its application in making MOFs with the largest pore aperture (98 A) and lowest density (0.13 g/cm3) This has allowed for the selective inclusion of large molecules (e.g. vitamin B12) and proteins (e.g. green fluorescent protein) and the exploitation of the pores as reaction vessels. Along these lines, the thermal and chemical stability of many MOFs has made them amenable to postsynthetic covalent organic and metal complex functionalization. These capabilities enable substantial enhancement of gas storage in MOFs and have led to their extensive study in the catalysis of organic reactions, activation of small molecules (hydrogen, methane, and water) gas separation, biomedical imaging, and proton, electron, and ion conduction. At present, methods are being developed for making nanocrystals and supercrystals of MOFs for their incorporation into devices. Outlook The precise control over the assembly of MOFs is expected to propel this field further into new realms of synthetic chemistry in which far more sophisticated materials may be accessed. For example, materials can be envisaged as having (i) compartments linked together to operate separately, yet function synergistically; (ii) dexterity to carry out parallel operations; (iii) ability to count, sort, and code information; and (iv) capability of dynamics with high fidelity. Efforts in this direction are already being undertaken through the introduction of a large number of different functional groups within the pores of MOFs. This yields multivariate frameworks in which the varying arrangement of functionalities gives rise to materials that offer a synergistic combination of properties. Future work will involve the assembly of chemical structures from many different types of building unit, such that the structures' function is dictated by the heterogeneity of the specific arrangement of their constituents. Strategies for Metal Organic Frameworks Metal organic frameworks are porous materials that can exhibit very high surface areas that have potential for applications such as gas storage and separation, as well as catalysis. Furukawa et al. (1230444) review the structures devised so far and discuss the design strategies that allow families of materials to be synthesized and modified with similar framework topology but vary in pore size and type of functional groups present on the linkers. Crystalline metal organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.
author_names: Hiroyasu Furukawa

Kyle E Cordova

M O'keeffe

Omar M Yaghi
title: The Chemistry and Applications of Metal Organic Frameworks
venue: Science
year: 2013

abstract: 1 The Atmosphere. 2 Atmospheric Trace Constituents. 3 Chemical Kinetics. 4 Atmospheric Radiation and Photochemistry. 5 Chemistry of the Stratosphere. 6 Chemistry of the Troposphere. 7 Chemistry of the Atmospheric Aqueous Phase. 8 Properties of the Atmospheric Aerosol. 9 Dynamics of Single Aerosol Particles. 10 Thermodynamics of Aerosols. 11 Nucleation. 12 Mass Transfer Aspects of Atmospheric Chemistry. 13 Dynamics of Aerosol Populations. 14 Organic Atmospheric Aerosols. 15 Interaction of Aerosols with Radiation. 16 Meteorology of the Local Scale. 17 Cloud Physics. 18 Atmospheric Diffusion. 19 Dry Deposition. 20 Wet Deposition. 21 General Circulation of the Atmosphere. 22 Global Cycles: Sulfur and Carbon. 23 Climate and Chemical Composition of the Atmosphere. 24 Aerosols and Climate. 25 Atmospheric Chemical Transport Models. 26 Statistical Models.
author_names: John H Seinfeld

Spyros N Pandis
title: Atmospheric Chemistry and Physics: From Air Pollution to Climate Change
year: 1997

abstract: The chemistry of graphene oxide is discussed in this critical review. Particular emphasis is directed toward the synthesis of graphene oxide, as well as its structure. Graphene oxide as a substrate for a variety of chemical transformations, including its reduction to graphene like materials, is also discussed. This review will be of value to synthetic chemists interested in this emerging field of materials science, as well as those investigating applications of graphene who would find a more thorough treatment of the chemistry of graphene oxide useful in understanding the scope and limitations of current approaches which utilize this material (91 references)
author_names: Daniel R Dreyer

Sungjin Park

Christopher W Bielawski

Rodney S Ruoff
title: The chemistry of graphene oxide.
venue: Chemical Society reviews
year: 2010

abstract: CRC handbook of chemistry and physics CRC handbook of chemistry and physics khtbkhnh mrkhzy dnshgh `lwm pzshkhy thrn
author_names: William M Haynes
title: CRC Handbook of Chemistry and Physics
year: 1990

author_names: Paul J Flory
title: Principles of polymer chemistry
year: 1953

abstract: Cyclooxygenase 2 isozyme is a promising anti inflammatory drug target, and overexpression of this enzyme is also associated with several cancers and neurodegenerative diseases. The amino acid sequence and structural similarity between inducible cyclooxygenase 2 and housekeeping cyclooxygenase 1 isoforms present a significant challenge to design selective cyclooxygenase 2 inhibitors. Herein, we describe the use of the cyclooxygenase 2 active site as a reaction vessel for the in situ generation of its own highly specific inhibitors. Multi component competitive binding studies confirmed that the cyclooxygenase 2 isozyme can judiciously select most appropriate chemical building blocks from a pool of chemicals to build its own highly potent inhibitor. Herein, with the use of kinetic target guided synthesis, also termed as in situ click chemistry, we describe the discovery of two highly potent and selective cyclooxygenase 2 isozyme inhibitors. The in vivo anti inflammatory activity of these two novel small molecules is significantly higher than that of widely used selective cyclooxygenase 2 inhibitors.Traditional inflammation and pain relief drugs target both cyclooxygenase 1 and 2 (COX 1 and COX 2) causing severe side effects. Here, the authors use in situ click chemistry to develop COX 2 specific inhibitors with high in vivo anti inflammatory activity.
author_names: Atul Bhardwaj

Jatinder Kaur

Melinda Wuest

Frank Wuest
title: In situ click chemistry generation of cyclooxygenase 2 inhibitors
venue: Nature Communications
year: 2016

author_names: David R Lide
title: Handbook of Chemistry and Physics
year: 1992