New theoretical insight into the thermal cis–trans isomerization of azo compounds: Protonation lowers the activation barrier

2001 ◽  
Vol 114 (13) ◽  
pp. 5504-5508 ◽  
Author(s):  
W. A. Sokalski ◽  
R. W. Góra ◽  
W. Bartkowiak ◽  
P. Kobyliński ◽  
J. Sworakowski ◽  
...  
Keyword(s):  
Activation Barrier ◽  
Azo Compounds ◽  
Trans Isomerization ◽  
Theoretical Insight ◽  
Insight Into

Theoretical insight into the CdS/FAPbI3 heterostructure: a promising visible-light absorber

2021 ◽  
Author(s):  
Junli Chang ◽  
Liping Jiang ◽  
Guangzhao Wang ◽  
Yuhong Huang ◽  
Hong Chen
Keyword(s):  
Optical Absorption ◽  
Visible Light ◽  
Visible Light Range ◽  
Light Absorber ◽  
Absorption Performance ◽  
Theoretical Insight ◽  
Insight Into

The optical absorption performance of the perovskite FAPbI3 in the visible-light range is significantly improved by constructing a CdS/FAPbI3 heterostructure.

scholarly journals Theoretical Insight into the Reversal of Chemoselectivity in Diels-Alder Reactions of α,β-Unsaturated Aldehydes and Ketones Catalyzed by Brønsted and Lewis Acids

Organics ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 38-49
Author(s):  
Lakhdar Benhamed ◽  
Sidi Mohamed Mekelleche ◽  
Wafaa Benchouk
Keyword(s):  
Lewis Acids ◽  
Major Product ◽  
Diels Alder ◽  
Unsaturated Ketone ◽  
Unsaturated Aldehydes ◽  
Aldehydes And Ketones ◽  
Theoretical Insight ◽  
Insight Into ◽  
Good Agreement

Experimentally, a reversal of chemoselectivity has been observed in catalyzed Diels–Alder reactions of α,β-unsaturated aldehydes (e.g., (2E)-but-2-enal) and ketones (e.g., 2-hexen-4-one) with cyclopentadiene. Indeed, using the triflimidic Brønsted acid Tf2NH as catalyst, the reaction gave a Diels–Alder adduct derived from α,β-unsaturated ketone as a major product. On the other hand, the use of tris(pentafluorophenyl)borane B(C6F5)3 bulky Lewis acid as catalyst gave mainly the cycloadduct of α,β-unsaturated aldehyde as a major product. Our aim in the present work is to put in evidence the role of the catalyst in the reversal of the chemoselectivity of the catalyzed Diels–Alder reactions of (2E)-but-2-enal and 2-Hexen-4-one with cyclopentadiene. The calculations were performed at the ωB97XD/6-311G(d,p) level of theory and the solvent effects of dichloromethane were taken into account using the PCM solvation model. The obtained results are in good agreement with experimental outcomes.

What makes court-referred mediation effective?

2014 ◽  
Vol 25 (1) ◽  
pp. 21-37 ◽  
Author(s):  
Amira Galin
Keyword(s):  
Design Methodology ◽  
Content Type ◽  
Process And Outcome ◽  
Refusal To Participate ◽  
The Impact ◽  
Practical Implications ◽  
Theoretical Insight ◽  
Insight Into ◽  
Low Rate

Purpose – The purpose of this paper is to obtain insight into court-referred mediation in the Israeli Labor Courts, by analyzing its processes and outcomes, as a function of tactics used by both the disputants and the mediator. Design/methodology/approach – Observation of 103 court-referred mediations, for each of which a detailed process and outcome were documented. Data on disputants' refusal to participate in the mediation was also collected. At the end of each mediation case, disputants were given a questionnaire in which they expressed their satisfaction with the outcome and their evaluation of the mediator's contribution. Findings – A low rate of refusal to participate in court-referred mediation was found. Also, the higher the ratio of soft tactics to pressure tactics employed (by all parties involved) during the process, the higher the rate of agreements. Mediators use significantly more soft tactics than disputants, and are more active in using tactics. The two significant variables that predict the mediation's agreement are the ratio between soft tactics to pressure tactics used by all parties, and mediator contribution to the process. Practical implications – The significant role of soft tactics in the process, outcome, and satisfaction of court-referred mediation may serve as a guideline for disputants and mediators. Originality/value – This unique research, which examines the impact of tactics on court-referred mediation, may provide added and significant theoretical insight into its process and outcome, as well as a better understanding of other “hybrid” (compulsory at the beginning, voluntary at the end) mediations.

Mechanistic Study on Gold(I)-Catalyzed Unsaturated Spiroketalization Reaction

2022 ◽  
Vol 19 ◽  
Author(s):  
Kamlesh Sharma
Keyword(s):  
Activation Barrier ◽  
Ring Formation ◽  
Hydroxyl Group ◽  
Mechanistic Study ◽  
Protecting Group ◽  
Wide Range ◽  
Oxocarbenium Ion ◽  
Metal Catalyzed ◽  
Insight Into ◽  
Mechanism Of The Reaction

Abstract: The mechanism of metal-catalyzed spiroketalization of propargyl acetonide is explored by employing DFT with the B3LYP/6-31+G(d) method. Acetonide is used as a regioselective regulator in the formation of monounsaturated spiroketal. The energies of transition states, intermediates, reactants and products are calculated to provide new insight into the mechanism of the reaction. The energetic features, validation of the observed trends in regioselectivity are conferred in terms of electronic indices via FMO analysis. The presence of acetonide facilitates a stepwise spiroketalization as it masks the competing nucleophile, and thus hydroxyl group present, exclusively acts as a nucleophile. The vinyl gold intermediate 3 is formed from 2 via activation barrier TS1. This is the first ring formation, which is 6-exo-dig cyclization. The intermediate 3 is converted into allenyl ether 4, which isomerizes to the intermediate oxocarbenium ion 5 via activation barrier TS2. The intermediate 5 cyclizes to 6 via TS3. This is the second ring formation. The intermediate 6 on protodeauration turns into 6,6-monounsaturated spiroketal 7. It is concluded that acetonide as a protecting group serves the purpose, and thus a wide range of spiroketals can be prepared, regioselectivity.

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