Hasil untuk "Chemistry"

Timothy P. Lodge, P. C. Hiemenz

J. Ryu, P. Messersmith, Haeshin Lee

H. Werner, P. Knowles, F. Manby et al.

Molpro is a general purpose quantum chemistry software package with a long development history. It was originally focused on accurate wavefunction calculations for small molecules but now has many additional distinctive capabilities that include, inter alia, local correlation approximations combined with explicit correlation, highly efficient implementations of single-reference correlation methods, robust and efficient multireference methods for large molecules, projection embedding, and anharmonic vibrational spectra. In addition to conventional input-file specification of calculations, Molpro calculations can now be specified and analyzed via a new graphical user interface and through a Python framework.

B. Bradlyn, L. Elcoro, Jennifer Cano et al.

Since the discovery of topological insulators and semimetals, there has been much research into predicting and experimentally discovering distinct classes of these materials, in which the topology of electronic states leads to robust surface states and electromagnetic responses. This apparent success, however, masks a fundamental shortcoming: topological insulators represent only a few hundred of the 200,000 stoichiometric compounds in material databases. However, it is unclear whether this low number is indicative of the esoteric nature of topological insulators or of a fundamental problem with the current approaches to finding them. Here we propose a complete electronic band theory, which builds on the conventional band theory of electrons, highlighting the link between the topology and local chemical bonding. This theory of topological quantum chemistry provides a description of the universal (across materials), global properties of all possible band structures and (weakly correlated) materials, consisting of a graph-theoretic description of momentum (reciprocal) space and a complementary group-theoretic description in real space. For all 230 crystal symmetry groups, we classify the possible band structures that arise from local atomic orbitals, and show which are topologically non-trivial. Our electronic band theory sheds new light on known topological insulators, and can be used to predict many more.

R. Sheldon, J. Woodley

Matthew B. Plutschack, Bartholomäus Pieber, K. Gilmore et al.

M. H. Shaw, Jack Twilton, D. MacMillan

In recent years, photoredox catalysis has come to the forefront in organic chemistry as a powerful strategy for the activation of small molecules. In a general sense, these approaches rely on the ability of metal complexes and organic dyes to convert visible light into chemical energy by engaging in single-electron transfer with organic substrates, thereby generating reactive intermediates. In this Perspective, we highlight the unique ability of photoredox catalysis to expedite the development of completely new reaction mechanisms, with particular emphasis placed on multicatalytic strategies that enable the construction of challenging carbon–carbon and carbon–heteroatom bonds.

J. Zimmerman, P. Anastas, Hanno C. Erythropel et al.

The material basis of a sustainable society will depend on chemical products and processes that are designed following principles that make them conducive to life. Important inherent properties of molecules need to be considered from the earliest stage—the design stage—to address whether compounds and processes are depleting versus renewable, toxic versus benign, and persistent versus readily degradable. Products, feedstocks, and manufacturing processes will need to integrate the principles of green chemistry and green engineering under an expanded definition of performance that includes sustainability considerations. This transformation will require the best of the traditions of science and innovation coupled with new emerging systems thinking and systems design that begins at the molecular level and results in a positive impact on the global scale.

C. Hoyle, C. Bowman

John A. Keith, V. Vassilev-Galindo, Bingqing Cheng et al.

Machine learning models are poised to make a transformative impact on chemical sciences by dramatically accelerating computational algorithms and amplifying insights available from computational chemistry methods. However, achieving this requires a confluence and coaction of expertise in computer science and physical sciences. This Review is written for new and experienced researchers working at the intersection of both fields. We first provide concise tutorials of computational chemistry and machine learning methods, showing how insights involving both can be achieved. We follow with a critical review of noteworthy applications that demonstrate how computational chemistry and machine learning can be used together to provide insightful (and useful) predictions in molecular and materials modeling, retrosyntheses, catalysis, and drug design.

Muhammad Sajid, J. Płotka-Wasylka

Green analytical chemistry encourages reducing the use of toxic chemicals/reagents, using energy-efficient equipment, and generating minimal waste. The recent trends in analytical method development focus on the miniaturization of the sample preparation devices, the development of solventless or solvent-minimized extraction techniques, and the utilization of less toxic solvents. The twelve principles of GAC serve as a basic guideline for inducing greenness in the analytical procedures. Despite these guidelines, in many conditions, some undesired steps are unavoidable. Therefore, it is important to evaluate the greenness of analytical procedures to assess and, if possible, reduce their impact on the environment and workers. Several metrics have been developed for the evaluation of the greenness of analytical procedures. Analytical Eco-Scale, Green Analytical Procedure Index, and Analytical Greenness Metric are among some important tools for assessing the greenness of analytical procedures. All these metrics take different aspects of the analytical procedure into account to provide the green index of the procedure. This review covered these metrics, their principles, and examples of their application to selected analytical procedures. The advantages and limitations of these metrics with the perspective of common reader/user are presented. We believe that this paper will inspire many new perspectives and developments in this area.

Zhongmin Tang, Peiran Zhao, Han Wang et al.

Since the first connection between Fenton chemistry and biomedicine, numerous studies have been presented in this field. Comprehensive presentation of the guidance from Fenton chemistry and a summary of its representative applications in cancer therapy would help us understand and promote the further development of this field. This comprehensive review first supplies basic information regarding Fenton chemistry, including Fenton reactions and Fenton-like reactions. Subsequently, the current progress of Fenton chemistry is discussed, with some corresponding representative examples presented. Furthermore, the current strategies for further optimizing the performance of chemodynamic therapy guided by Fenton chemistry are highlighted. Most importantly, future perspectives on the combination of biomedicine with Fenton chemistry or a wider range of catalytic chemistry approaches are presented. We hope that this review will attract positive attention in the chemistry, materials science, and biomedicine fields and further tighten their connections.

C. Eaborn

J. Atwood, J. Lehn

N. G. Kampen, William P. Reinhardt

A. Ghose, and Vellarkad N. Viswanadhan, J. Wendoloski

J. March

F. Ponnamperuma

Peter Bellotti, Maximilian Koy, M. Hopkinson et al.