Room temperature generation of reactive intermediates Cp*Zr:O and Cp*2Zr:S: trapping reactions with unsaturated organic molecules and dative ligands

1990 ◽  
Vol 112 (17) ◽  
pp. 6426-6428 ◽  
Author(s):  
Michael J. Carney ◽  
Patrick J. Walsh ◽  
Robert G. Bergman
Keyword(s):  
Room Temperature ◽  
Organic Molecules ◽  
Reactive Intermediates ◽  
Trapping Reactions

Catch It If You Can: Copper-Catalyzed (Transfer) Hydrogenation Reactions and Coupling Reactions by Intercepting Reactive Intermediates Thereof

Synthesis ◽  
2020 ◽  
Vol 52 (17) ◽  
pp. 2483-2496
Author(s):  
Johannes F. Teichert ◽  
Lea T. Brechmann
Keyword(s):  
Coupling Reaction ◽  
Reactive Intermediates ◽  
Transfer Hydrogenation ◽  
Coupling Reactions ◽  
Bond Forming ◽  
Starting Point ◽  
Bond Forming Reactions ◽  
Hydrogenation Reactions ◽  
Multicomponent Coupling Reactions ◽  
Trapping Reactions

The key reactive intermediate of copper(I)-catalyzed alkyne semihydrogenations is a vinylcopper(I) complex. This intermediate can be exploited as a starting point for a variety of trapping reactions. In this manner, an alkyne semihydrogenation can be turned into a dihydrogen­-mediated coupling reaction. Therefore, the development of copper-catalyzed (transfer) hydrogenation reactions is closely intertwined with the corresponding reductive trapping reactions. This short review highlights and conceptualizes the results in this area so far, with H2-mediated carbon–carbon and carbon–heteroatom bond-forming reactions emerging under both a transfer hydrogenation setting as well as with the direct use of H2. In all cases, highly selective catalysts are required that give rise to atom-economic multicomponent coupling reactions with rapidly rising molecular complexity. The coupling reactions are put into perspective by presenting the corresponding (transfer) hydrogenation processes first.1 Introduction: H2-Mediated C–C Bond-Forming Reactions2 Accessing Copper(I) Hydride Complexes as Key Reagents for Coupling Reactions; Requirements for Successful Trapping Reactions 3 Homogeneous Copper-Catalyzed Transfer Hydrogenations4 Trapping of Reactive Intermediates of Alkyne Transfer Semi­hydrogenation Reactions: First Steps Towards Hydrogenative Alkyne Functionalizations 5 Copper(I)-Catalyzed Alkyne Semihydrogenations6 Copper(I)-Catalyzed H2-Mediated Alkyne Functionalizations; Trapping of Reactive Intermediates from Catalytic Hydrogenations6.1 A Detour: Copper(I)-Catalyzed Allylic Reductions, Catalytic Generation of Hydride Nucleophiles from H2 6.2 Trapping with Allylic Electrophiles: A Copper(I)-Catalyzed Hydro­allylation Reaction of Alkynes 6.3 Trapping with Aryl Iodides7 Conclusion

Can an ammonium-based room temperature ionic liquid counteract the urea-induced denaturation of a small peptide?

2017 ◽  
Vol 19 (11) ◽  
pp. 7772-7787 ◽  
Author(s):  
Soumadwip Ghosh ◽  
Souvik Dey ◽  
Mahendra Patel ◽  
Rajarshi Chakrabarti
Keyword(s):  
Ionic Liquid ◽  
Aqueous Medium ◽  
Room Temperature ◽  
Organic Molecules ◽  
Room Temperature Ionic Liquid ◽  
Small Peptide ◽  
Small Organic Molecules

The folding/unfolding equilibrium of proteins in aqueous medium can be altered by adding small organic molecules generally termed as co-solvents.

Room-Temperature Ceramic Nanocoating Using Nanosheet Deposition Technique

2013 ◽  
Vol 2013 (CICMT) ◽  
pp. 000014-000018 ◽  
Author(s):  
M. Osada ◽  
T. Sasaki
Keyword(s):  
Room Temperature ◽  
Organic Molecules ◽  
Structural Diversity ◽  
Layer By Layer ◽  
Precise Control ◽  
Langmuir Blodgett ◽  
Wide Range ◽  
Potential Applications ◽  
Layer Assembly ◽  
Selection Of

We present a novel procedure for ceramic nanocoating using oxide nanosheet as a building block. A variety of oxide nanosheets (such as Ti1−δO2, MnO2 and perovsites) were synthesized by delaminating appropriate layered precursors into their molecular single sheets. These nanosheets are exceptionally rich in both structural diversity and electronic properties, with potential applications including conductors, semiconductors, insulators, and ferromagnets. Another attractive aspect is that nanosheets can be organized into various nanoarchitectures by applying solution-based synthetic techniques involving electrostatic layer-by-layer assembly and Langmuir-Blodgett deposition. It is even possible to tailor superlattice assemblies, incorporating into the nanosheet galleries with a wide range of materials such as organic molecules, polymers, and inorganic/metal nanoparticles. Sophisticated functionalities or paper-like devices can be designed through the selection of nanosheets and combining materials, and precise control over their arrangement at the molecular scale.

scholarly journals Complex Uranyl Dichromates Templated by Aza-Crowns

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 462 ◽  
Author(s):  
Oleg Siidra ◽  
Evgeny Nazarchuk ◽  
Dmitry Charkin ◽  
Stepan Kalmykov ◽  
Anastasiya Zadoya
Keyword(s):  
Aqueous Solutions ◽  
Crown Ethers ◽  
Room Temperature ◽  
Organic Molecules ◽  
Negative Charge ◽  
Uranyl Compounds ◽  
One Dimensional ◽  
Chain Complexes ◽  
Aza Crown Ethers

Three new uranyl dichromate compounds templated by aza-crown templates were obtained at room temperature by evaporation from aqueous solutions: (H2diaza-18-crown-6)2[(UO2)2(Cr2O7)4(H2O)2](H2O)3 (1), (H4[15]aneN4)[(UO2)2(CrO4)2(Cr2O7)2(H2O)] (H2O)3.5 (2) and (H4Cyclam)(H4[15]aneN4)2[(UO2)6(CrO4)8(Cr2O7)4](H2O)4 (3). The use of aza-crown templates made it possible to isolate unprecedented and complex one-dimensional units in 2 and 3, whereas the structure of 1 is based on simple uranyl-dichromate chains. It is very likely that the presence of relatively large organic molecules of aza-crown ethers does not allow uranyl chromate chain complexes to condense into the units of higher dimensionality (layers or frameworks). In general, the formation of 1, 2, and 3 is in agreement with the general principles elaborated for organically templated uranyl compounds. The negative charge of the [(UO2)(Cr2O7)2(H2O)]2−, [(UO2)2(CrO4)2(Cr2O7)2(H2O)]4− and [(UO2)3(CrO4)4(Cr2O7)2]6− one-dimensional inorganic motifs is compensated by the protonation of all nitrogen atoms in the molecules of aza-crowns.

Bose–Einstein Condensation of Exciton-Polaritons in Organic Microcavities

2020 ◽  
Vol 71 (1) ◽  
pp. 435-459 ◽  
Author(s):  
Jonathan Keeling ◽  
Stéphane Kéna-Cohen
Keyword(s):  
Room Temperature ◽  
Organic Molecules ◽  
Einstein Condensation ◽  
Electronic Excitations ◽  
Optical Mode ◽  
Optical Cavities ◽  
Bose Einstein Condensation ◽  
Exciton Polaritons ◽  
Basic Physics ◽  
Bose Einstein

Bose–Einstein condensation describes the macroscopic occupation of a single-particle mode: the condensate. This state can in principle be realized for any particles obeying Bose–Einstein statistics; this includes hybrid light-matter excitations known as polaritons. Some of the unique optoelectronic properties of organic molecules make them especially well suited for the realization of polariton condensates. Exciton-polaritons form in optical cavities when electronic excitations couple collectively to the optical mode supported by the cavity. These polaritons obey bosonic statistics at moderate densities, are stable at room temperature, and have been observed to form a condensed or lasing state. Understanding the optimal conditions for polariton condensation requires careful modeling of the complex photophysics of organic molecules. In this article, we introduce the basic physics of exciton-polaritons and condensation and review experiments demonstrating polariton condensation in molecular materials.

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