CH2 + O2: Reaction mechanism, biradical and zwitterionic character, and formation of CH2OO, the simplest Criegee Intermediate

2021 ◽  
Author(s):  
Elham Mazarei ◽  
John R. Barker
Keyword(s):  
Reaction Mechanism ◽  
Wave Functions ◽  
Title Reaction ◽  
Potential Surfaces

The singlet and triplet potential surfaces for the title reaction were investigated using the CBS-QB3 level of theory. The wave functions for some species exhibited multireference character and required the...

scholarly journals Heavy baryon production with an instanton interaction

2020 ◽  
Vol 2020 (5) ◽  
Author(s):  
Sang-In Shim ◽  
Atsushi Hosaka ◽  
Hyun-Chul Kim
Keyword(s):  
Reaction Mechanism ◽  
Quark Model ◽  
Heavy Baryon ◽  
Wave Functions ◽  
Baryon Production ◽  
Production Rates ◽  
Charmed Baryons ◽  
Charmed Baryon ◽  
Strange Baryons ◽  
Large Production

Abstract We propose a new reaction mechanism for the study of strange and charmed baryon production. In this mechanism we consider the correlation of two quarks in baryons, so it can be called the two-quark process. As in the previously studied one-quark process, we find large production rates for charmed baryons in comparison with strange baryons. Moreover, the new mechanism causes the excitation of both the $\rho$ mode and the $\lambda$ mode. Using the wave functions for baryons from a quark model, we compute the production rates of various baryon states. We find that the production rates reflect the structure of the wave functions that imply the usefulness of the reactions for the study of baryon structures.

A Multifunctional Reagent Designed for the Site-Selective Amination of Pyridines

2020 ◽  
Author(s):  
Patrick Fier ◽  
Suhong Kim ◽  
Ryan Cohen
Keyword(s):  
Reaction Mechanism ◽  
Direct Conversion ◽  
Single Step ◽  
The Novel ◽  
Title Reaction ◽  
Mild Conditions ◽  
Unique Reaction ◽  
Unexpected Findings ◽  
Site Selective

We report the development of a multifunctional reagent for the direct conversion of pyridines to Boc-protected 2-aminopyridines with exquisite site- and chemoselectivity. The novel reagent was prepared on 200 gram-scale in a single step, reacts in the title reaction under mild conditions without precautions towards air or moisture, and is tolerant of nearly all common functionality. Experimental and <i>in-situ </i>spectroscopic<i> </i>monitoring techniques provide detailed insights and unexpected findings for the unique reaction mechanism.

Study of Cyclization of 1-Benzoyl-3-methyl-3-(2-methoxycarbonylphenyl)thiourea to 1-Methyl-2-thioxo-4-quinazolone

1993 ◽  
Vol 58 (5) ◽  
pp. 1122-1132 ◽  
Author(s):  
Jaromír Kaválek ◽  
Vladimír Macháček ◽  
Miloš Sedlák ◽  
Vojeslav Štěrba
Keyword(s):  
Reaction Mechanism ◽  
Kinetic Study ◽  
Title Reaction ◽  
Initial Substance ◽  
Second Stage ◽  
Rate Determining Step ◽  
Benzoyl Group ◽  
Two Stages ◽  
The Given

The reaction mechanism of the title reaction was proposed on the bases of the kinetic study. The reaction takes place in two stages considerably differing in rates. In the first, faster stage, the anion of initial substance cyclizes to 1-methyl-3-benzoyl-2-thioxo-4-quinazolone. The reaction is reversible, the concentration of 1-methyl-3-benzoyl-2-thioxo-4-quinazolone decreases with increasing concentration of methanolate. In the second stage, the benzoyl group rearrangement in the given substance from nitrogen to sulfur and subsequent methanolysis to 1-methyl-2-thioxo-4-quinazolone take place. The rate-determining step is the methanolysis for [CH3O(-)] < 4 . 10-3 mol l-1 and the benzoyl group rearrangement for higher methanolate concentrations.

RHO PRODUCTION IN PROTON-NUCLEUS COLLISION

1999 ◽  
Vol 08 (03) ◽  
pp. 243-256 ◽  
Author(s):  
SWAPAN DAS ◽  
B. K. JAIN ◽  
A. B. SANTRA
Keyword(s):  
Reaction Mechanism ◽  
Cross Sections ◽  
Target Nucleus ◽  
Beam Energy ◽  
Plane Waves ◽  
Bound State ◽  
Wave Functions ◽  
Decay Probability ◽  
Hadron Masses ◽  
The Continuum

With the final aim to explore the effect of the medium on hadron masses we study the reaction mechanism for the (p,p′ρ0) reaction on nuclei. We focus on the amplitudes which are dominated by the N*(1720)P13 resonance in intermediate state. This resonance has about 80% decay probability to Nρ channel. A nonrelativistic formalism is written for different amplitudes. The theoretical cross sections are presented for the 12 C target nucleus around 3 GeV beam energy. These results are found to be sensitive to the N* as well as ρ mass modifications in the medium. These two effects in the p′ spectrum can be separated experimentally as they are found to occur at different values of the p′ momentum. Because of the exploratory nature of this investigation, simple forms are used for the bound-state wave functions, and the continuum particles are approximated by plane waves.

Mechanism, selectivity, and reactivity of iridium- and rhodium-catalyzed intermolecular ketone α-alkylation with unactivated olefinsviaan enamide directing strategy

2018 ◽  
Vol 8 (9) ◽  
pp. 2417-2426 ◽  
Author(s):  
Xiaojie Li ◽  
Hongli Wu ◽  
Yanmin Lang ◽  
Genping Huang
Keyword(s):  
Reaction Mechanism ◽  
Dft Calculations ◽  
Title Reaction ◽  
Detailed Reaction Mechanism

DFT calculations were performed to investigate the title reaction, focusing on detailed reaction mechanism and origins of selectivity and reactivity.

DOES P-YLIDIC RADICAL FEATURE THE YLIDIC OR RADICAL CHARACTER TOWARD FORMALDEHYDE?

2007 ◽  
Vol 06 (03) ◽  
pp. 531-540
Author(s):  
HONG-BIN XIE ◽  
YI-HONG DING
Keyword(s):  
Reaction Mechanism ◽  
Model Reaction ◽  
Orbital Interaction ◽  
Frontier Orbital ◽  
Orbital Theory ◽  
Title Reaction ◽  
Theoretical Investigations ◽  
Elimination Mechanism ◽  
Radical Character ◽  
Analogical Process

Theoretical investigations are preformed on the model reaction of PH 3 CH + H 2 CO to unravel reactivity of PH 3 CH , so-called Ylide-like radical, at G3MP2 and CCSD(T)/aug-cc-pVDZ//MP2/6-311++G(d,p) level. The results indicate that P -Ylidic radical behaves differently from the P -Ylide or usual unsaturated radical toward formaldehyde. For the entrance channels, [2+2] cycloaddition to form oxaphosphetane radical INT1 is more favorable, which is an analogical process to Witting reaction of P -Ylide. So PH 3 CH shows P -Ylide character in entrance channel, which has found the support from the dual one-center frontier–orbital interaction based on Fukui's frontier–orbital theory. However, due to the radical character of INT1, it can competitively give P2 PH 3 CHCHO + H and INT2, but not Witting-type products of alkene and phosphine oxide. At last, INT2 almost can barrierlessly fragmentate to Corey-type products of ethene oxide radical and phosphine. The present study shows that PH 3 CH , Ylide-like radical, has duplicate reactivity of both P-Ylide and radical, and title reaction presents a completely new reaction mechanism, compared with previous well-known H -abstract or addition–elimination mechanism for radical- H 2 CO reactions.

Interaction of the Vibrational and Electronic Motions in Some Simple Conjugated Hydrocarbons

1961 ◽  
Vol 16 (7) ◽  
pp. 641-668 ◽  
Author(s):  
Andrew D. Liehr
Keyword(s):  
Molecular Conformation ◽  
Power Series Expansion ◽  
Critical Discussion ◽  
Wave Functions ◽  
Computational Techniques ◽  
Potential Surfaces ◽  
Electronic Wave ◽  
Lennard Jones ◽  
Jahn Teller ◽  
Electronic Wave Functions

A semiempirical theory of vibrational and electronic reciprocation, in both degenerate and nondegenerate electronic states, is developed under the assumptions that (1) a molecule may be accurately described by the adiabatic approximation; (2) solutions of the electronic and vibrational SCHRÖ-DINGER equations for some fixed molecular conformation are available; (3) the electronic wave functions may be analytically continued to vicinal geometries; (4) the power series expansion of the electronic wave functions and HAMILTONian operator, in terms of nuclear displacements, may be truncated at degree two; and (5) first order perturbation theory is applicable.The formulae derived for nondegenerate electronic distributions are employed to compute the intensities of the HERZBERG-TELLER (“vibronic”) type absorptions of normal benzene, the cyclopentadienide ion, and the tropylium ion. For convenience in numerically evaluating the requisite phenomenological vibronic constants, the LENNARD-JONES approximation is introduced. The resultant accord of experiment and theory is good.To test the educed mathematical expressions for either essentially or fortuitously degenerate electronic dispositions, extremal energy calculations are performed for the cyclobutadiene and benzene molecules, the cyclopentadienyl radical, and the benzene plus one ion. It is found, in agreement with the JAHN-TELLER theorem, that all these systems are configurationally unstable with respect to some asymmetric nuclear displacement. The utilization of the LENNARD-JONES approximation again permits a numerical specification of the required vibronic parameters. Application is then made to the ultraviolet spectrum of benzene: the second singlet absorption system and the RYDBERG spectrum are theoretically interpreted in the light of the reckoned predictions. An attempt is made to answer the four cogent queries of WILKINSON concerning the nature of JAHN-TELLER interactions in the RYDBERG spectrum of benzene.A mathematical and pictorial description of the nuclear dynamics of JAHN-TELLER and HERZBERG–TELLER molecules is also given, and the portraitures of the underlying potential surfaces are verbally and diagrammatically painted. In addition, a critical discussion of the reality of both the computational techniques and of the emergent algebraic forms is presented, and paths for future progress are indicated. A censorius discourse on the flagrant abuse of the phrase “JAHN-TELLER effect” is appended; it is recommended that its use be restricted to the dynamical manifestations of the theorem of JAHN and TELLER (e. g., forbidden asymmetric vibrational progressions and abnormal paramagnetic behavior). Statical demonstrations of the theorem are better ascribed to intrinsic JAHN-TELLER instability.

A Multifunctional Reagent Designed for the Site-Selective Amination of Pyridines

2020 ◽  
Author(s):  
Patrick Fier ◽  
Suhong Kim ◽  
Ryan Cohen
Keyword(s):  
Reaction Mechanism ◽  
Direct Conversion ◽  
Single Step ◽  
The Novel ◽  
Title Reaction ◽  
Mild Conditions ◽  
Unique Reaction ◽  
Unexpected Findings ◽  
Site Selective

We report the development of a multifunctional reagent for the direct conversion of pyridines to Boc-protected 2-aminopyridines with exquisite site- and chemoselectivity. The novel reagent was prepared on 200 gram-scale in a single step, reacts in the title reaction under mild conditions without precautions towards air or moisture, and is tolerant of nearly all common functionality. Experimental and <i>in-situ </i>spectroscopic<i> </i>monitoring techniques provide detailed insights and unexpected findings for the unique reaction mechanism.

Arylation of enelactams using TIPSOTf: reaction scope and mechanistic insight

2021 ◽  
Author(s):  
Tomasz J. Idzik ◽  
Zofia M. Myk ◽  
Łukasz Struk ◽  
Magdalena Perużyńska ◽  
Gabriela Maciejewska ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Multinuclear Nmr ◽  
Mechanistic Insight ◽  
Nmr Study ◽  
Wide Range

Triisopropylsilyltrifluoromethanesulfonate can be effectively used for the arylation of a wide range of enelactams. The multinuclear NMR study provided deep insights into the reaction mechanism.

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