scholarly journals A DFT Study of the Hexene Hydrogenation Catalysed by the Complex RuH(CO)(Cl)(PCy3): Monophosphine vs Diphosphine Paths

2019 ◽  
Author(s):  
Zied Hosni ◽  
Bahoueddine Tangour ◽  
Sofiene Achour
Keyword(s):  
Hydrogen Transfer ◽  
Direct Consequence ◽  
Dft Study ◽  
Energy Profile ◽  
Enthalpy Of Activation ◽  
Model Complex ◽  
The One ◽  
Phosphine Complex ◽  
H2 Molecule ◽  
Catalyst Model

A DFT study of hexene hydrogenation catalysed by the RuH(CO)(Cl)(PCy3)2 complex is presented. The investigation explores the feasibility of two different mechanisms: the first exploits a single phosphine complex and the second uses a two phosphines complex. The energy barriers involving a hydrogen transfer have a ten kcal.mol-1 higher than the one obtained through the single-phosphine mechanism. These results confirm the experimental hypothesis claiming that the departure of a phosphine is favourable at the beginning of the reaction which is the substitution of the catalyst model RuHCl(CO)(PMe3)2 by the real catalyst RuHCl(CO)(PCy3)2 shows no significant influence on the energetic barriers of hexene hydrogenation mechanism. The most important step of the mechanism is the kinetically determining step. The heterolytic cleavage of ruthenium-complexed H2 molecule leads to the generation of two Ru-H bonds and the oxidation of the ruthenium from Ru(II) to Ru(IV). The energy profile of this step is not relative to an elementary reaction because a shouldering is observed after the transition state. This results in an unusual gradient norm profile with five extrema. This is a direct consequence of the asynchronous nature of the different processes taking place during this step. In the case of the model complex RuHCl(CO)(IMes)(PMe3) with IMes = ( N , N '-bis( mesityl)imidazol-2-ylidene), an increase of the free enthalpy of activation is observed during the kinetically determining step, which is in agreement with the experimental work.

A DFT Study of the Hexene Hydrogenation Catalysed by the Complex RuH(CO)(Cl)(PCy3): Monophosphine vs Diphosphine Paths

2019 ◽  
Author(s):  
Zied Hosni ◽  
Bahoueddine Tangour ◽  
Sofiene Achour
Keyword(s):  
Hydrogen Transfer ◽  
Direct Consequence ◽  
Dft Study ◽  
Energy Profile ◽  
Enthalpy Of Activation ◽  
Model Complex ◽  
The One ◽  
Phosphine Complex ◽  
H2 Molecule ◽  
Catalyst Model

A DFT study of hexene hydrogenation catalysed by the RuH(CO)(Cl)(PCy3)2 complex is presented. The investigation explores the feasibility of two different mechanisms: the first exploits a single phosphine complex and the second uses a two phosphines complex. The energy barriers involving a hydrogen transfer have a ten kcal.mol-1 higher than the one obtained through the single-phosphine mechanism. These results confirm the experimental hypothesis claiming that the departure of a phosphine is favourable at the beginning of the reaction which is the substitution of the catalyst model RuHCl(CO)(PMe3)2 by the real catalyst RuHCl(CO)(PCy3)2 shows no significant influence on the energetic barriers of hexene hydrogenation mechanism. The most important step of the mechanism is the kinetically determining step. The heterolytic cleavage of ruthenium-complexed H2 molecule leads to the generation of two Ru-H bonds and the oxidation of the ruthenium from Ru(II) to Ru(IV). The energy profile of this step is not relative to an elementary reaction because a shouldering is observed after the transition state. This results in an unusual gradient norm profile with five extrema. This is a direct consequence of the asynchronous nature of the different processes taking place during this step. In the case of the model complex RuHCl(CO)(IMes)(PMe3) with IMes = ( N , N '-bis( mesityl)imidazol-2-ylidene), an increase of the free enthalpy of activation is observed during the kinetically determining step, which is in agreement with the experimental work.

Statistical Mechanics of Thermotransport of a Heavy Impurity in an Insulating Solid

1971 ◽  
Vol 26 (1) ◽  
pp. 10-17 ◽  
Author(s):  
A. R. Allnatt
Keyword(s):  
Heat Flux ◽  
Time Correlation ◽  
Three Dimensions ◽  
Time Correlation Functions ◽  
Single Vacancy ◽  
One Dimensional ◽  
Enthalpy Of Activation ◽  
Heavy Impurity ◽  
The One ◽  
Non Equilibrium

AbstractA kinetic equation is derived for the singlet distribution function for a heavy impurity in a lattice of lighter atoms in a temperature gradient. In the one dimensional case the equation can be solved to find formal expressions for the jump probability and hence the heat of transport, q*. for a single vacancy jump of the impurity, q* is the sum of the enthalpy of activation, a term involving only averaging in an equilibrium ensemble, and two non-equilibrium terms in­volving time correlation functions. The most important non-equilibrium term concerns the cor­relation between the force on the impurity and a microscopic heat flux. A plausible extension to three dimensions is suggested and the relation to earlier isothermal and non-isothermal theories is indicated

To what question is the Badiouan notion of the subject an answer? On the dialectical elaboration of the concept in his early work

2016 ◽  
Vol 43 (1) ◽  
pp. 96-120
Author(s):  
Jan-Jasper Persijn
Keyword(s):  
Direct Consequence ◽  
The Other ◽  
The Political ◽  
Academic World ◽  
Systematic Account ◽  
Political Field ◽  
Political Implications ◽  
The Subject ◽  
The One ◽  
Work Up

Alain Badiou’s elaboration of a subject faithful to an event is commonly known today in the academic world and beyond. However, his first systematic account of the subject ( Théorie du Sujet) was already published in 1982 and did not mention the ‘event’ at all. Therefore, this article aims at tracing back both the structural and the historical conditions that directed Badiou’s elaboration of the subject in the early work up until the publication of L’Être et l’Événément in 1988. On the one hand, it investigates to what extent the (early) Badiouan subject can be considered an exceptional product of the formalist project of the Cahiers pour l’Analyse as instigated by psychoanalytical discourse (Lacan) and a certain Marxist discourse (Althusser) insofar as both were centered upon a theory of the subject. On the other hand, this article examines the radical political implications of this subject insofar as Badiou has directed his philosophical aims towards the political field as a direct consequence of the events of May ’68.

scholarly journals Preliminary synthesis of algorithms for automatic control of automobile continuously variable transmissions with flexible links

2020 ◽  
Vol 1 (4) ◽  
pp. 25-37
Author(s):  
A.E. Yesakov ◽  
◽  
A.V. Kretov ◽  
P.A. Krasavin ◽  
◽  
...  
Keyword(s):  
Automatic Control ◽  
Direct Consequence ◽  
Continuously Variable Transmission ◽  
Factors Affecting ◽  
Flexible Links ◽  
Automatic Control Systems ◽  
High Durability ◽  
Continuously Variable Transmissions ◽  
Variable Transmission ◽  
The One

Variators of different operating principles and designs are of interest as components of automatic transmissions for ground transport and traction machines. At the same time, one of the most popular types of variators are the variators built on the basis of continuously variable transmissions with flexible links. The main reasons for the use of such variators in the transmissions of a number of modern passenger vehicles are, on the one hand, the emergence of flexible link designs with high durability, and, on the other hand, the widespread introduction of programmable electronic devices into automatic control systems for continuously variable transmissions. A direct consequence of the latter circumstance was the need for in-depth research aimed at synthesizing such control algorithms that would make it possible to fully use the advantages inherent in continuously variable transmissions with flexible links and minimize the operational consequences of their shortcomings. This paper makes an attempt to solve the problem of synthesizing the algorithm in a preliminary form, based on the goal of providing the vehicle with the best traction and speed properties. The presence of such an attempt will allow, having set the main parameters of a continuously variable transmission for some reason, to develop the hardware of the automatic control system. In turn, this will make it possible to synthesize a refined algorithm that takes into account the dynamics of the system, errors of meters and signal conversion devices, as well as other factors affecting work pro-cesses. When considering the described problem, various variants of the geometry of the contact surfaces of the continuously variable transmission links were taken into account and the corre-sponding mathematical apparatus were formed. The results of calculations, obtained by computer program that implements these devices, are selectively presented in the materials of the paper.

Comment on ‘Energy profile of the one-dimensional Klein–Gordon oscillator’

2011 ◽  
Vol 84 (3) ◽  
pp. 037001 ◽  
Author(s):  
Abdelmalek Boumali ◽  
Abdelhakim Hafdallah ◽  
Amina Toumi
Keyword(s):  
Energy Profile ◽  
One Dimensional ◽  
Klein Gordon ◽  
The One

Research Trends of the Labour Market in 2016

2016 ◽  
Vol 5 (4) ◽  
pp. 71-77
Author(s):  
Захаров ◽  
Dmitriy Zakharov
Keyword(s):  
Labor Market ◽  
Staff Development ◽  
Professional Growth ◽  
Human Resources Management ◽  
Direct Consequence ◽  
Market Participants ◽  
Top Managers ◽  
Market Situation ◽  
The Stability ◽  
The One

This article discusses the current trends, analysis and forecasts of the labor market situation in Russia. Results the effect of the global economic crisis on the labor market. It was revealed that the crisis has forced workers significantly revise their professional requirements. In particular, today the Russian top managers and key specialists emphasize employment is the stability of the company in the market, even the prospects for career and professional growth overshadowed. The recommendations on the adjustment of human resources management strategy of the organization, taking into account trends and forecasts of the labor market. The new targets have to work with the company personnel are performance evaluation and staff development. These strategic priorities, on the one hand — a direct consequence of the difficulties in the economy, dictating the most balanced market participants to expend resources, on the other hand — an attempt to control service personnel to reach a new level of business.

Stereocontrolled synthesis of propionate motifs froml-lactic andl-alanine aldehydes. A DFT study of the hydrogen transfer under endocyclic control

2014 ◽  
Vol 1 (8) ◽  
pp. 974-982 ◽  
Author(s):  
François Godin ◽  
Martin Duplessis ◽  
Cindy Buonomano ◽  
Thao Trinh ◽  
Karine Houde ◽  
...  
Keyword(s):  
Hydrogen Transfer ◽  
Dft Study ◽  
Stereocontrolled Synthesis

scholarly journals Hydrogen transfer reaction: Bond formation and bond cleavage through the eyes of interacting quantum atoms

2019 ◽  
Vol 84 (8) ◽  
pp. 891-900
Author(s):  
Branislav Milovanovic ◽  
Mihajlo Etinski ◽  
Milena Petkovic
Keyword(s):  
Hydrogen Atom ◽  
Density Functional ◽  
Hydrogen Transfer ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Minimum Energy ◽  
Fragment Analysis ◽  
Interacting Quantum Atoms ◽  
Methoxy Radical ◽  
The One

Hydrogen transfer from hydroquinone to the methoxy radical was studied using the density functional theory. The energy decomposition technique, interacting quantum atoms, was employed for a detailed investigation of the changes that the bonds of interest go through along the minimum energy path in the vicinity of the transition state. The whole system was divided either into two or three fragments. The two-fragment analysis enabled investigation of the bond that is formed or the one that is cleaved by defining the fragments as reactants and as products, respectively. The three-fragment analysis (the fragments being semiquinone, hydrogen atom and methoxy radical) was used for the simultaneous analysis of the two phenomena, bond cleavage and bond formation. Additionally, it enabled the interaction between the particle that donates the hydrogen atom and the one that accepts it to be investigated. This interaction is characterized by attractive non-classical and repulsive classical interactions. It was demonstrated that the transferring hydrogen atom undergoes the most pronounced energy changes and gives the largest contribution to the deformation energy.

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