Mechanism and Activity of Ruthenium Olefin Metathesis Catalysts:  The Role of Ligands and Substrates from a Theoretical Perspective

2004 ◽  
Vol 126 (11) ◽  
pp. 3496-3510 ◽  
Author(s):  
Christian Adlhart ◽  
Peter Chen
Keyword(s):  
Olefin Metathesis ◽  
Theoretical Perspective ◽  
Metathesis Catalysts

scholarly journals MOF Encapsulation of Ru Olefin Metathesis Catalysts to Block Catalyst Decomposition

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 687
Author(s):  
Gerard Pareras ◽  
Davide Tiana ◽  
Albert Poater
Keyword(s):  
Olefin Metathesis ◽  
Density Functional ◽  
Metal Organic Framework ◽  
Functional Theory ◽  
Ammonium N ◽  
Metathesis Catalyst ◽  
Metal Organic ◽  
Non Covalent Interactions ◽  
Metathesis Catalysts

In the present work, a catalyst variation of the second-generation Hoveyda–Grubbs catalyst, particularly the ammonium-tagged Ru-alkylidene metathesis catalyst AquaMetTM, is under study, not simply to increase the efficiency in olefin metathesis but also the solubility in polar solvents. Moreover, this ionic catalyst was combined with the metal organic framework (MOF) (Cr)MIL-101-SO3−(Na·15-crown-5)+. We started from the experimental results by Grela et al., who increased the performance when the ruthenium catalyst was confined inside the cavities of the MOF, achieving non-covalent interactions between both moieties. Here, using density functional theory (DFT) calculations, the role of the ammonium N-heterocyclic carbene (NHC) tagged and the confinement effects are checked. The kinetics are used to compare reaction profiles, whereas SambVca steric maps and NCI plots are used to characterize the role of the MOF structurally and electronically.

scholarly journals Metathesis access to monocyclic iminocyclitol-based therapeutic agents

2011 ◽  
Vol 7 ◽  
pp. 699-716 ◽  
Author(s):  
Ileana Dragutan ◽  
Valerian Dragutan ◽  
Carmen Mitan ◽  
Hermanus CM Vosloo ◽  
Lionel Delaude ◽  
...  
Keyword(s):  
Olefin Metathesis ◽  
Metabolic Disorders ◽  
Therapeutic Agents ◽  
Comparative Performance ◽  
Common Diseases ◽  
Metathesis Reactions ◽  
Recent Developments ◽  
Metathesis Catalysts ◽  
Steric Control

By focusing on recent developments on natural and non-natural azasugars (iminocyclitols), this review bolsters the case for the role of olefin metathesis reactions (RCM, CM) as key transformations in the multistep syntheses of pyrrolidine-, piperidine- and azepane-based iminocyclitols, as important therapeutic agents against a range of common diseases and as tools for studying metabolic disorders. Considerable improvements brought about by introduction of one or more metathesis steps are outlined, with emphasis on the exquisite steric control and atom-economical outcome of the overall process. The comparative performance of several established metathesis catalysts is also highlighted.

d0Re-Based Olefin Metathesis Catalysts, Re(⋮CR)(CHR)(X)(Y):  The Key Role of X and Y Ligands for Efficient Active Sites

2005 ◽  
Vol 127 (40) ◽  
pp. 14015-14025 ◽  
Author(s):  
Xavier Solans-Monfort ◽  
Eric Clot ◽  
Christophe Copéret ◽  
Odile Eisenstein
Keyword(s):  
Olefin Metathesis ◽  
Active Sites ◽  
Metathesis Catalysts

The role of nursing in the rehabilitation of acute stroke patients: Toward a unified theoretical perspective

Pflege ◽  
1999 ◽  
Vol 12 (1) ◽  
pp. 21-27
Author(s):  
Marit Kirkevold
Keyword(s):  
Acute Stroke ◽  
Theoretical Perspective ◽  
Stroke Patients ◽  
Role Of Nursing ◽  
Rolle Der Pflegenden

Eine Übersicht der bestehenden Literatur weist auf Unsicherheiten bezüglich der spezifischen Rolle der Pflegenden in der Rehabilitation von Hirnschlagpatientinnen und -patienten hin. Es existieren zwei unterschiedliche Begrifflichkeiten für die Rolle der Pflegenden, keine davon bezieht sich auf spezifische Rehabilitationsziele oder Patientenergebnisse. Ein anfänglicher theoretischer Beitrag der Rolle der Pflege in der Genesung vom Hirnschlag wird als Struktur unterbreitet, um die therapeutischen Aspekte der Pflege im Koordinieren, Erhalten und Üben zu vereinen. Bestehende Literatur untermauert diesen Beitrag. Weitere Forschung ist jedoch notwendig, um den spezifischen Inhalt und Fokus der Pflege in der Genesung bei Hirnschlag zu entwickeln.

Democratization in Serbia: An Analysis of Rational Choice and Structuralist Explanations

2015 ◽  
Author(s):  
Dunja Apostolov-Dimitrijevic
Keyword(s):  
Rational Choice ◽  
Path Dependence ◽  
Theoretical Perspective ◽  
Political Leadership ◽  
Decisive Role ◽  
The Other ◽  
Internal Factors ◽  
Transitional Societies ◽  
The Face

This paper explains political democratization in Post-Milosevic Serbia, utilizing two different accounts of the democratization process: one rooted in the rational choice framework and the other in structuralism. While rational choice explains the decisive role of political leadership in overcoming path dependence, the structuralist explanations show the transnational linkages that encourage democratization in the face of domestic setbacks. This particular debate between the two types of explanations represents the larger debate concerning the role of internal factors and external linkages in propelling democratization in transitional societies. The paper concludes by integrating the two sets of explanations offered by each theoretical perspective, in order to develop a coherent understanding of Serbia's democratization.   Full text available at: https://doi.org/10.22215/rera.v9i1.240

Debiasing the Outcome Effect: The Role of Instructions in an Audit Litigation Setting

2002 ◽  
Vol 21 (2) ◽  
pp. 7-20 ◽  
Author(s):  
Peter M. Clarkson ◽  
Craig Emby ◽  
Vanessa W.-S. Watt
Keyword(s):  
Theoretical Perspective ◽  
Cognitive Components ◽  
Audit Judgment ◽  
Outcome Information ◽  
Audit Litigation ◽  
Outcome Bias ◽  
Biasing Effects ◽  
Judgment Setting

The outcome effect occurs where an evaluator, who has knowledge of the outcome of a judge's decision, assesses the quality of the judgment of that decision maker. If the evaluator has knowledge of a negative outcome, then that knowledge negatively influences his or her assessment of the ex ante judgment. For instance, jurors in a lawsuit brought against an auditor for alleged negligence are informed of an undetected fraud, even though an unqualified opinion was issued. This paper reports the results of an experiment in an applied audit judgment setting that examined methods of mitigating the outcome effect by means of instructions. The results showed that simply instructing or warning the evaluator about the potential biasing effects of outcome information was only weakly effective. However, instructions that stressed either (1) the cognitive nonnormativeness of the outcome effect or (2) the seriousness and gravity of the evaluation ameliorated the effect significantly. From a theoretical perspective, the results suggest that there may both motivational and cognitive components to the outcome effect. In all, the findings suggest awareness of the outcome effect and use of relatively nonintrusive instructions to evaluators may effectively counteract the potential for the outcome bias.

Elements of language creativity

Semiotica ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Simone Casini
Keyword(s):  
Theoretical Perspective ◽  
Ancient Philosophy ◽  
Frame Of Reference ◽  
Linguistic Change ◽  
Social Sharing

Abstract This paper proposes a concept of creativity that stems from a semiotic and linguistic theoretical perspective, in which the formal frame of reference for variation and linguistic change considers and evaluates both the process of general interaction and the contact of languages as a global phenomenon. This method proposes an analysis of creativity that ranges from reflections of ancient philosophy to a contemporary linguistic perspective, incorporates international ideologies, and identifies, within the dimensions of use and social sharing, the principle capable of guiding potentially unlimited forms of linguistic creativity that are self-expressive and communicative, far beyond the grammatical patterns of regularity and norm. Interpreting the paradigm of creativity according to this model means placing the semiotic property in a position of prima inter pares, entrusted not only with the “role” of forming signs (words, sentences, texts), but the function of arbitraire, as a phenomenon of language creation. The following reading references the semiotic contribution of Tullio De Mauro, an Italian linguist who has contributed to the systematization of creativity, overcoming and synthesizing both Saussurian structuralism and Chomskyan generativism.

Activated Hoveyda‐Grubbs Olefin Metathesis Catalysts Derived from a Large Scale Produced Pharmaceutical Intermediate—Sildenafil Aldehyde

2021 ◽  
Author(s):  
Louis Monsigny ◽  
Jakub Piątkowski ◽  
Damian Trzybiński ◽  
Krzysztof Wozniak ◽  
Tomasz Nienałtowski ◽  
...  
Keyword(s):  
Olefin Metathesis ◽  
Large Scale ◽  
Metathesis Catalysts

Nitrenium ions and trivalent boron ligands as analogues of N-heterocyclic carbenes in olefin metathesis: a computational study

2015 ◽  
Vol 44 (46) ◽  
pp. 20021-20026 ◽  
Author(s):  
A. Pazio ◽  
K. Woźniak ◽  
K. Grela ◽  
B. Trzaskowski
Keyword(s):  
Olefin Metathesis ◽  
Computational Study ◽  
Heterocyclic Carbenes ◽  
Mechanistic Study ◽  
Nitrenium Ions ◽  
Nitrenium Ion ◽  
Metathesis Catalysts

A DFT mechanistic study reveals that nitrenium ion-modified Hoveyda-like complexes are good candidates for latent metathesis catalysts, while boron-modified systems are candidates for very fast metathesis catalysts.

Sign in / Sign up

Export Citation Format

Share Document