Copper–organic frameworks assembled from in situ generated 5-(4-pyridyl)tetrazole building blocks: synthesis, structural features, topological analysis and catalytic oxidation of alcohols

2014 ◽  
Vol 43 (26) ◽  
pp. 9944-9954 ◽  
Author(s):  
Rajendar Nasani ◽  
Manideepa Saha ◽  
Shaikh M. Mobin ◽  
Luísa M. D. R. S. Martins ◽  
Armando J. L. Pombeiro ◽  
...  
Keyword(s):  
High Activity ◽  
Catalytic Oxidation ◽  
Topological Analysis ◽  
Secondary Alcohol ◽  
Building Blocks ◽  
Structural Features ◽  
Oxidation Of Alcohols

Two copper based MOFs generated by cycloaddition of nitrile and azide show high activity towards oxidation of secondary alcohol.

scholarly journals Cu3Pt1–Cu2O nanocomposites: synergistic effect-dependent high activity and stability for the gas-phase selective oxidation of alcohols

RSC Advances ◽  
2017 ◽  
Vol 7 (86) ◽  
pp. 54861-54865 ◽  
Author(s):  
Kun Liu ◽  
Houkun Long ◽  
Guangyi Wang ◽  
Yongbin Sun ◽  
Chao Hou ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
High Activity ◽  
Gas Phase ◽  
Selective Oxidation ◽  
Oxidation Of Alcohols

The catalyst Cu3Pt1–Cu2O/SiC was facilely prepared via the in situ reaction of the corresponding compounds supported on SiC in the reaction stream.

Structural consequences of weak interactions in dispirooxindole derivatives

2015 ◽  
Vol 71 (11) ◽  
pp. 1001-1009
Author(s):  
Krishnan Ravikumar ◽  
Balasubramanian Sridhar ◽  
Jagadeesh Babu Nanubolu ◽  
Govindaraju Karthik ◽  
Basi Venkata Subba Reddy
Keyword(s):  
Weak Interactions ◽  
Noncovalent Interactions ◽  
Building Blocks ◽  
Cascade Reactions ◽  
Structural Features ◽  
Molecular Assembly ◽  
Diastereoselective Synthesis ◽  
Structural Variations ◽  
Racemic Mixtures

Spiro scaffolds are being increasingly utilized in drug discovery due to their inherent three-dimensionality and structural variations, resulting in new synthetic routes to introduce spiro building blocks into more pharmaceutically active molecules. Multicomponent cascade reactions, involving thein situgeneration of carbonyl ylides from α-diazocarbonyl compounds and aldehydes, and 1,3-dipolar cycloadditon with 3-arylideneoxindoles gave a novel class of dispirooxindole derivatives, namely 1,1′′-dibenzyl-5′-(4-chlorophenyl)-4′-phenyl-4′,5′-dihydrodispiro[indoline-3,2′-furan-3′,3′′-indoline]-2,2′′-dione, C44H33ClN2O3, (I), 1′′-acetyl-1-benzyl-5′-(4-chlorophenyl)-4′-phenyl-4′,5′-dihydrodispiro[indoline-3,2′-furan-3′,3′′-indoline]-2,2′′-dione, C39H29ClN2O4, (II), 1′′-acetyl-1-benzyl-4′,5′-diphenyl-4′,5′-dihydrodispiro[indoline-3,2′-furan-3′,3′′-indoline]-2,2′′-dione, C39H30N2O4, (III), and 1′′-acetyl-1-benzyl-4′,5′-diphenyl-4′,5′-dihydrodispiro[indoline-3,2′-furan-3′,3′′-indoline]-2,2′′-dione acetonitrile hemisolvate, C39H30N2O4·0.5C2H3N, (IV). All four compounds exist as racemic mixtures of theSSSRandRRRSstereoisomers. In these structures, the two H atoms of the dihydrofuran ring and the two substituted oxindole rings are in atransorientation, facilitating intramolecular C—H...O and π–π interactions. These weak interactions play a prominent role in the structural stability and aid the highly regio- and diastereoselective synthesis. In each of the four structures, the molecular assembly in the crystal is also governed by weak noncovalent interactions. Compound (IV) is the solvated analogue of (III) and the two compounds show similar structural features.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

A Pseudo Five-Fold Symmetrical Ligand Drives Geometric Frustration in Porous Metal-Organic and Hydrogen Bonded Frameworks

2020 ◽  
Author(s):  
Frederik Haase ◽  
Gavin Craig ◽  
Mickaele Bonneau ◽  
kunihisa sugimoto ◽  
Shuhei Furukawa
Keyword(s):  
Topological Defects ◽  
Porous Metal ◽  
Building Blocks ◽  
Structural Features ◽  
Equilibrium Structure ◽  
Sorption Behavior ◽  
Building Unit ◽  
Geometric Frustration ◽  
Secondary Building Units ◽  
Hydrogen Bonded

Reticular framework materials thrive on designability, but unexpected reaction outcomes are crucial in exploring new structures and functionalities. By combining “incompatible” building blocks, we employed geometric frustration in reticular materials leading to emergent structural features. The combination of a pseudo C<sub>5</sub> symmetrical organic building unit based on a pyrrole core, with a C<sub>4</sub> symmetrical copper paddlewheel synthon led to three distinct frameworks by tuning the synthetic conditions. The frameworks show structural features typical for geometric frustration: self-limiting assembly, internally stressed equilibrium structures and topological defects in the equilibrium structure, which manifested in the formation of a hydrogen bonded framework, distorted and broken secondary building units and dangling functional groups, respectively. The influence of geometric frustration on the CO<sub>2</sub> sorption behavior and the discovery of a new secondary building unit shows geometric frustration can serve as a strategy to obtain highly complex porous frameworks.

A Pseudo Five-Fold Symmetrical Ligand Drives Geometric Frustration in Porous Metal-Organic and Hydrogen Bonded Frameworks

2020 ◽  
Author(s):  
Frederik Haase ◽  
Gavin Craig ◽  
Mickaele Bonneau ◽  
kunihisa sugimoto ◽  
Shuhei Furukawa
Keyword(s):  
Topological Defects ◽  
Porous Metal ◽  
Building Blocks ◽  
Structural Features ◽  
Equilibrium Structure ◽  
Sorption Behavior ◽  
Building Unit ◽  
Geometric Frustration ◽  
Secondary Building Units ◽  
Hydrogen Bonded

Reticular framework materials thrive on designability, but unexpected reaction outcomes are crucial in exploring new structures and functionalities. By combining “incompatible” building blocks, we employed geometric frustration in reticular materials leading to emergent structural features. The combination of a pseudo C<sub>5</sub> symmetrical organic building unit based on a pyrrole core, with a C<sub>4</sub> symmetrical copper paddlewheel synthon led to three distinct frameworks by tuning the synthetic conditions. The frameworks show structural features typical for geometric frustration: self-limiting assembly, internally stressed equilibrium structures and topological defects in the equilibrium structure, which manifested in the formation of a hydrogen bonded framework, distorted and broken secondary building units and dangling functional groups, respectively. The influence of geometric frustration on the CO<sub>2</sub> sorption behavior and the discovery of a new secondary building unit shows geometric frustration can serve as a strategy to obtain highly complex porous frameworks.

Application of Nitrogen Heterocyclic Carbenes in Organocatalysis

2020 ◽  
Vol 09 ◽  
Author(s):  
Minita Ojha ◽  
R. K. Bansal
Keyword(s):  
Asymmetric Catalysis ◽  
Building Blocks ◽  
Structural Features ◽  
Heterocyclic Carbenes ◽  
Stetter Reaction ◽  
Metal Pollutants ◽  
Synthetic Strategy ◽  
Wide Range ◽  
Benzoin Condensation ◽  
Nitrogen Heterocyclic

Background: During the last two decades, horizon of research in the field of Nitrogen Heterocyclic Carbenes (NHC) has widened remarkably. NHCs have emerged as ubiquitous species having applications in a broad range of fields, including organocatalysis and organometallic chemistry. The NHC-induced non-asymmetric catalysis has turned out to be a really fruitful area of research in recent years. Methods: By manipulating structural features and selecting appropriate substituent groups, it has been possible to control the kinetic and thermodynamic stability of a wide range of NHCs, which can be tolerant to a variety of functional groups and can be used under mild conditions. NHCs are produced by different methods, such as deprotonation of Nalkylhetrocyclic salt, transmetallation, decarboxylation and electrochemical reduction. Results: The NHCs have been used successfully as catalysts for a wide range of reactions making a large number of building blocks and other useful compounds accessible. Some of these reactions are: benzoin condensation, Stetter reaction, Michael reaction, esterification, activation of esters, activation of isocyanides, polymerization, different cycloaddition reactions, isomerization, etc. The present review includes all these examples published during the last 10 years, i.e. from 2010 till date. Conclusion: The NHCs have emerged as versatile and powerful organocatalysts in synthetic organic chemistry. They provide the synthetic strategy which does not burden the environment with metal pollutants and thus fit in the Green Chemistry.

scholarly journals Exploring Cu/Al cluster growth and reactivity: from embryonic building blocks to intermetalloid, open-shell superatoms

2021 ◽  
Author(s):  
Max Schütz ◽  
Christian Gemel ◽  
Maximilian Muhr ◽  
Christian Jandl ◽  
Samia Kahlal ◽  
...  
Keyword(s):  
Closed Shell ◽  
Building Blocks ◽  
Open Shell ◽  
Cluster Growth ◽  
Powerful Technique

Cu/Al cluster growth reactions leading to open- and closed-shell superatoms are investigated. Therein, LIFDI-MS is presented as a powerful technique for the in situ detection of cluster identities and reactivity patterns.

scholarly journals Data Parallel Hypersweeps for in Situ Topological Analysis

2020 ◽  
Author(s):  
Petar Hristov ◽  
Gunther H. Weber ◽  
Hamish A. Carr ◽  
Oliver Rubel ◽  
James P. Ahrens
Keyword(s):  
Topological Analysis ◽  
Data Parallel
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