Understanding room-temperature π-dimerisation of radical ions: intramolecular π-[TTF]22+ in functionalised calix[4]arenes

2017 ◽  
Vol 19 (5) ◽  
pp. 3807-3819 ◽  
Author(s):  
Maria Fumanal ◽  
Marçal Capdevila-Cortada ◽  
Juan J. Novoa
Keyword(s):  
Dft Calculations ◽  
Room Temperature ◽  
Radical Ions

Room-temperature π-[TTF]22+ dimers in calix[4]arene derivatives unravelled by means of DFT calculations.

Atomistic prediction on the configuration- and temperature-dependent dielectric constant of Be0.25Mg0.75O superlattice as a high-κ dielectric layer

2021 ◽  
Author(s):  
Gyuseung Han ◽  
In Won Yeu ◽  
Kun Hee Ye ◽  
Seung-Cheol Lee ◽  
Cheol Seong Hwang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dft Calculations ◽  
Bond Length ◽  
Dielectric Layer ◽  
Room Temperature ◽  
High Dielectric Constant ◽  
Temperature Dependent ◽  
High Dielectric

Through DFT calculations, a Be0.25Mg0.75O superlattice having long apical Be–O bond length is proposed to have a high bandgap (>7.3 eV) and high dielectric constant (∼18) at room temperature and above.

scholarly journals Investigations on non-classical silylium ions leading to a cyclobutenyl cation

2019 ◽  
Vol 10 (9) ◽  
pp. 2821-2829 ◽  
Author(s):  
Arthur Martens ◽  
Marvin Kreuzer ◽  
Alexander Ripp ◽  
Marius Schneider ◽  
Daniel Himmel ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Room Temperature ◽  
The Way

The formation of simple non-classical silylium ions from [Me3Si]+ sources and alkenes or alkynes was investigated, but mainly oligomerization was observed. Yet, the reaction with MeCCMe led to a room temperature stable cyclobutenyl cation. DFT calculations suggest that a non-classical silylium ion intermediate was formed on the way to this product.

Schwefelradikale S3– in Natriumtetrasulfid bei erhöhter Temperatur.

1976 ◽  
Vol 31 (4) ◽  
pp. 411-414 ◽  
Author(s):  
Hans Hermann Eysel ◽  
Dietrich Nöthe
Keyword(s):  
Solid State ◽  
Absorption Spectra ◽  
Strong Evidence ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Radical Ions ◽  
Visible Absorption ◽  
Electrode Processes ◽  
Sodium Sulfur

Raman EPR and visible absorption spectra of sodium tetrasulfide in the solid state and melts have been studied from room temperature up to 300°C. The above techniques provide strong evidence for breaking of the polysulfide chains resulting in the production of S3-radical ions. The existence of the radical ions in polysulfides at elevated temperatures is important for understanding the electrode processes in sodium sulfur batteries.

Surface-assisted cis–trans isomerization of an alkene molecule on Cu(110)

2014 ◽  
Vol 50 (14) ◽  
pp. 1728-1730 ◽  
Author(s):  
Qiang Sun ◽  
Chi Zhang ◽  
Likun Wang ◽  
Zhiwen Li ◽  
Aiguo Hu ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Room Temperature ◽  
Ultrahigh Vacuum ◽  
Trans Isomerization ◽  
Isomerization Process

Interplay of STM imaging and DFT calculations demonstrates the isomerization of an alkene molecule on Cu(110) under ultrahigh vacuum conditions. We show that the on-surfacecis–transisomerization could efficiently occur well below room temperature, in which the surface is speculated to play a key role in assisting this isomerization process.

scholarly journals Synthesis of 5-arylacetylene 1,2,4-oxadiazoles and their transformations under superelectrophilic activation conditions

2021 ◽  
Author(s):  
Andrey I Puzanov ◽  
Dmitry S Ryabukhin ◽  
Anna S Zalivatskaya ◽  
Dmitriy N Zakusilo ◽  
Darya S Mikson ◽  
...  
Keyword(s):  
Double Bond ◽  
Dft Calculations ◽  
Reaction Mechanisms ◽  
Room Temperature ◽  
Triflic Acid ◽  
Activation Conditions ◽  
First Time ◽  
Vinyl Triflates ◽  
Derivatives Of ◽  
Acetylene Derivatives

Acetylene derivatives of 1,2,4-oxadiazoles, 5-(2-arylethynyl)-3-aryl-1,2,4-oxadiazoles, have been obtained, for the first time, from 5-(2-arylethenyl)-3-aryl-1,2,4-oxadiazoles by their bromination at the carbon-carbon double bond followed by di-dehydrobromination with NaNH2 in liquid NH3.  Reaction of the acetylene 1,2,4-oxadiazoles with arenes in neat triflic acid TfOH (CF3SO3H) at room temperature for 1 h result in the formation of E-/Z-5-(2,2-diarylethenyl)-3-aryl-1,2,4-oxadiazoles as products of regioselective hydroarylation of the acetylene bond. Addition of TfOH to acetylene bond of these oxadiazoles gives rise quantitatively to E-/Z-vinyl triflates. Reaction cationic intermediates have been studied by DFT calculations. The reaction mechanisms have been discussed.

Hydroarylation of olefins catalysed by a dimeric ytterbium(II) alkyl

2021 ◽  
Author(s):  
GM Richardson ◽  
I Douair ◽  
Scott Cameron ◽  
Joe Bracegirdle ◽  
Robert Keyzers ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Density Functional ◽  
Room Temperature ◽  
Main Group ◽  
Functional Theory

Although the nucleophilic alkylation of aromatics has recently been achieved with a variety of potent main group reagents, all of this reactivity is limited to a stoichiometric regime. We now report that the ytterbium(II) hydride, [BDI YbH] (BDI = CH[C(CH )NDipp] , Dipp = 2,6-diisopropylphenyl), reacts with ethene and propene to provide the ytterbium(II) n-alkyls, [BDI YbR] (R = Et or Pr), both of which alkylate benzene at room temperature. Density functional theory (DFT) calculations indicate that this latter process operates through the nucleophilic (S 2) displacement of hydride, while the resultant regeneration of [BDI YbH] facilitates further reaction with ethene or propene and enables the direct catalytic (anti-Markovnikov) hydroarylation of both alkenes with a benzene C-H bond. Dipp Dipp Dipp Dipp 2 3 2 2 N 2

On-surface construction of a metal–organic Sierpiński triangle

2015 ◽  
Vol 51 (75) ◽  
pp. 14164-14166 ◽  
Author(s):  
Qiang Sun ◽  
Liangliang Cai ◽  
Honghong Ma ◽  
Chunxue Yuan ◽  
Wei Xu
Keyword(s):  
High Resolution ◽  
Dft Calculations ◽  
Room Temperature ◽  
Sierpinski Triangle ◽  
Metal Organic ◽  
Surface Construction

From the interplay of high-resolution STM imaging and DFT calculations we demonstrate the first example of a metal–organic fractal (Sierpiński triangle) on the surface, and also the first room-temperature stable 2D supramolecular Sierpiński triangle.

scholarly journals Dipolar addition to cyclic vinyl sulfones leading to dual conformation tricycles

2013 ◽  
Vol 9 ◽  
pp. 1419-1425 ◽  
Author(s):  
Steven S Y Wong ◽  
Michael G Brant ◽  
Christopher Barr ◽  
Allen G Oliver ◽  
Jeremy E Wulff
Keyword(s):  
Dft Calculations ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Synthetic Methodology ◽  
Nitrogen Center ◽  
Azomethine Imines ◽  
Nmr Methods

Dipolar addition of cyclic azomethine imines with cyclic vinyl sulfones gave rise to functionalized tricycles that exhibited fluxional behavior in solution at room temperature. The scope of the synthetic methodology was explored, and the origin of the fluxional behavior was probed by NMR methods together with DFT calculations. This behavior was ultimately attributed to stereochemical inversion at one of two nitrogen centers embedded in the tricyclic framework. Two tetracycles were also synthesized, and the degree of signal-broadening in the NMR spectra was found to depend on the presence of substitution next to the inverting nitrogen center.

scholarly journals Superelectrophilic activation of 5-hydroxymethylfurfural and 2,5-diformylfuran: organic synthesis based on biomass-derived products

2016 ◽  
Vol 12 ◽  
pp. 2125-2135 ◽  
Author(s):  
Dmitry S Ryabukhin ◽  
Dmitry N Zakusilo ◽  
Mikhail O Kompanets ◽  
Anton A.Tarakanov ◽  
Irina A Boyarskaya ◽  
...  
Keyword(s):  
High Pressure ◽  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Organic Synthesis ◽  
Room Temperature ◽  
Trifluoromethanesulfonic Acid ◽  
Reaction Products ◽  
Triflic Acid ◽  
Pressure Tubes ◽  
Acidic Zeolites

The reaction of 5-hydroxymethylfurfural (5-HMF) with arenes in superacidic trifluoromethanesulfonic acid (triflic acid, TfOH) as the solvent at room temperature for 1–24 h gives rise to 5-arylmethylfurfurals (yields of 17–91%) and 2-arylmethyl-5-(diarylmethyl)furans (yields of 10–37%). The formation of these two types of reaction products depends on the nucleophilicity of the arene. The same reactions under the action of acidic zeolites H-USY in high pressure tubes at 130 °C for 1 h result in the formation of only 5-arylmethylfurfurals (yields of 45–79%). 2,5-Diformylfuran (2,5-DFF) in the reaction with arenes under the action of AlBr3 at room temperature for 1 h leads to 5-(diarylmethyl)furfurals (yields of 51–90%). The reactive protonated species of 5-HMF and 2,5-DFF were characterized by NMR spectroscopy in TfOH and studied by DFT calculations. These reactions show possibilities of organic synthesis based on biomass-derived 5-HMF and 2,5-DFF.

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