Search
Now showing items 2501-2510 of 3701
Mechanistic Insights in the Mode of Action of Bifunctional Pyrrolidine-Squaramide-derived Organocatalysts
(Wiley-VCH, 2016)
The modes of catalytic action of three squaramide-derived
bifunctional organocatalysts have been investigated using DFT
methods. The [5+2] cycloaddition between oxidopyrilium ylides and
enals has been used as model ...
Organocatalytically Generated Donor − Acceptor Cyclopropanes in Domino Reactions. One-Step Enantioselective Synthesis of Pyrrolo[1,2 ‑ a ]quinolines
(American Chemical Society, 2016-03-18)
An easy and straightforward procedure has been developed for the synthesis of highly enantioenriched pyrrolo-[1,2-a]quinolines through a one-pot process that comprises a domino cyclopropane ring opening/aza-Michael/aldol ...
Organocatalytic Transannular Approach to Stereodefined Bicyclo[3.1.0]hexanes
(American Chemical Society, 2018-03-12)
A diastereodivergent approach to highly substituted bicyclo[3.1.0]hexanes has been developed through a transannular alkylation reaction that builds up the bicyclic core employing asymmetric organocatalysis as the tool for ...
Racemic hemiacetals as oxygen-centered pronucleophiles triggering cascade 1,4-addition/ Michael reaction through dynamic kinetic resolution under iminium catalysis. Development and mechanistic insights
(Royal Society of Chemistry, 2017-04-01)
2-Hydroxydihydropyran-5-ones behave as excellent polyfunctional reagents able to react with enals through oxa-Michael/Michael process cascade under the combination of iminium and enamine catalysis. These racemic hemiacetalic ...
Palladium(II)-catalyzed Intramolecular C-H Alkenylation for the Synthesis of Chromanes
(American Chemical Society, 2019-01-14)
The intramolecular Pd(II)-catalyzed alkenylation of aryl homoallyl ethers constitutes a mild,
versatile, and efficient procedure for the synthesis of highly and diversely substituted chromanes, and
2H-chromenes. The use ...
Magnetocaloric effect enhancement driven by intrinsic defects in Ni-Mn-Sn- Co alloys
(Elsevier, 2019-02-05)
[EN] The influence of mechanically-induced defects on the magnetostructural properties is analyzed in a Ni-Co-Mn-Sn alloy subjected to soft milling and subsequent annealing treatments. It is found that, opposite to what ...
119Sn Mössbauer Spectroscopy for assessing the local stress and defect state towards the tuning of Ni-Mn-Sn alloys
(AIP, 2017-05-02)
[EN] The influence of defects and local stresses on the magnetic properties and martensitic transformation in Ni50Mn35Sn15 is studied at macroscopic and atomic scale levels. We show that both the structural and magnetic ...
Identification of Ni-vacancy defect in Ni-Mn-Z (Z = Ga, Sn, In): An experimental and DFT positron annihilation study
(APS, 2019-02-21)
[EN] By means of experimental positron-annihilation-lifetime measurements and theoretical density functional theory (DFT) positron-lifetime calculations, vacancy-type defects in Ni50Mn50−xSnx (x=25, 20,15,13,10) and ...
Observation of a charge delocalization from Se vacancies in Bi2Se3: A positron annihilation study of native defects
(APS, 2016-07-27)
[EN] By means of positron annihilation lifetime spectroscopy, we have investigated the native defects present in Bi2Se3, which belongs to the family of topological insulators. We experimentally demonstrate that selenium ...
Experimental observation of vacancy assisted martensitic transformation shift in Ni-Fe-Ga alloys
(APS, 2019-04-23)
[EN] Positron annihilation lifetime spectroscopy is used to experimentally demonstrate the direct relationship between vacancies and the shift of the martensitic transformation temperature in a Ni55Fe17Ga28 alloy. The ...