Search results for "Function"

Closer Investigation of the Kinetics and Mechanism of Spirovinylcyclopropyl Oxindole Reaction with 3Σ–g-O2 by Topological Approaches and Unraveling t…

2021

In this investigation at the MN15L/Def2-TZVP level of theory, we present computational evidence indicating that the reaction of 3Σ-g-O2 with spirovinylcyclopropyl oxindole (2) leads to a product called spiro-1,2-dioxolane (2) in its singlet state; this reaction occurs via a stepwise mechanism and its rate-determining step is catalyzed by iodine radicals, which promotes opening of the three-membered ring under dark conditions. The conversion of 2 to 1-benzylindoline-2,3-dione (3) and 2-vinyloxirane (4) takes place via a concerted and slightly asynchronous reaction. Both electron localization function and AIM topological analysis reveal that the step associated with the attack of the 3Σ-g-O2 …

ChemInform Abstract: Fluorous TBAF: A Convenient and Selective Reagent for Fluoride-Mediated Deprotections.

2010

A fluorous analogue of TBAF has been developed for its use in the clean removal of silicon-derived protecting groups. Purification of the crude mixtures by fluorous solid-phase extractions allowed alcohols, amines, and carboxylic acids to be obtained in high purity, with no need of chromatographic separations. The moderate reactivity of fluorous TBAF was exploited in selective deprotections of several bifunctional molecules.

Synthese von methyl- und methylenosubstituierten p-Oligophenylenen durch cokondensierende ULLMANN-Reaktion. 12. Mitt.

1963

Es wird ein Syntheseverfahren fur p-Oligophenylene beschrieben, das eine Variante der ULLMANNschen Biarylverknupfungsreaktion darstellt. Dabei wird eine bifunktionelle Jodverbindung mit einem groseren Uberschus an einer monofunktionellen Komponente umgesetzt. Dieses als cokondensierende ULLMANN-Reaktion bezeichnete Syntheseprinzip, das Ausbeuten von 40–50% d. Th. ergibt, wird eingehend erlautert und die Leistungsfahigkeit an zahlreichen Beispielen belegt. Neben einer Reihe von methylsubstituierten p-Oligophenylenen, welche Derivate vom p-Terphenyl bis zum p-Septiphenyl einschliest, werden auch Oligophenylene mit endstandigem oder mittelstandigem Fluorenrest als Strukturelement hergestellt. …

Smoking and Oxidative Stress: Vascular Damage

2007

Gold assisted oxygen dissociation on a molybdenum-doped CaO(001) surface

2016

Using density functional theory (DFT) calculations, we address the adsorption of O2 and the coadsorption of gold species and oxygen molecules on a Mo-doped CaO(001) surface with 1.25% impurity concentration. With the help of the Born–Haber thermodynamic cycle, the enhanced binding of an oxygen molecule on Ca(Mo)O is attributed to energy gain owing to simultaneous electron transfer from the dopant to the molecule and lattice relaxations. We consider three coadsorption structures for an Au atom and O2 molecule with different Au–O2 distances. The calculations demonstrate that the coadsorption structures take one electron from the dopant and the O–Au–O chain structure is thermodynamically more …

l-Arabinose Conformers Adsorption on Ruthenium Surfaces: A DFT Study

2012

Adsorption of 5 L-arabinose tautomers – one acyclic and four cyclic (α and β, pyranose and furanose) species – on a ruthenium surface was studied as a precursor-process of the, nowadays more and more, industrially important sugar catalytic hydrogenation on metal surfaces in water medium. The study was mostly referred to a 37-atom metal catalyst fragment, even though border-effects on the adsorption processes were also checked employing a 61-atom metal fragment. In order to figure out conformational effects on the title process the tautomer flexibility was, at first, investigated by the genetic-algorithm based code Balloon, considering the conformational spaces of the different aquo tautomer…

Excited State N−H Tautomer Selectivity in the Singlet Energy Transfer of a Zinc(II)-Porphyrin-Truxene-Corrole Assembly

2017

International audience; An original corrole-containing polyad for S-1 energy transfer, in which one zinc(II)-porphyrin donor is linked to two free-base corrole acceptors by a truxene linker, is reported. This polyad exhibits a rapid zinc(II)-porphyrin*free-base corrole transfer (4.83x10(10)s(-1); 298K), even faster than the tautomerization in the excited state processes taking advantage of the good electronic communication provided by the truxene bridge. Importantly, the energy transfer process shows approximately 3-fold selectivity for one corrole N-H tautomer over the other even at low temperature (77K). This selectivity is due to the difference in the J-integral being effective in both t…

Synthesis of novel fluorinated building blocks via halofluorination and related reactions.

2020

A study exploring halofluorination and fluoroselenation of some cyclic olefins, such as diesters, imides, and lactams with varied functionalization patterns and different structural architectures is described. The synthetic methodologies were based on electrophilic activation through halonium ions of the ring olefin bonds, followed by nucleophilic fluorination with Deoxo-Fluor®. The fluorine-containing products thus obtained were subjected to elimination reactions, yielding various fluorine-containing small-molecular entities.

Ring-opening metathesis of some strained bicyclic systems; stereocontrolled access to diolefinated saturated heterocycles with multiple stereogenic c…

2018

Ring-opening metathesis (ROM) of various unsaturated, constrained bicyclic ring systems has been investigated with the use of commercial ruthenium-based catalysts. Starting from various cyclodienes, the corresponding derived bicyclic lactone, lactam, and isoxazoline derivatives were submitted to ROM under ethenolysis. These functionalized, strained bicyclic systems afforded novel highly-functionalized diolefinated heterocyclic scaffolds in ROM reactions with stereocontrol, through the conservation of the configuration of the stereogenic centers of the starting compounds.

A Functional Analysis of the Finnish 2012 Presidential Elections

2016

This study applied the functional theory of political campaign discourse, developed for political campaigns in the United States to two televised presidential debates in the 2012 presidential elections in Finland. Acclaims were the most preferred statement by the candidates, with agreements being the least preferred. Policy was discussed more than character during the debates. General goals and ideals were used more frequently to acclaim than to attack. Results are generally consistent with the results of previous studies of presidential elections in the US and other countries. However, differences did emerge: the classical functional categories were supplemented by a new category, the role…