Theoretical insight into the hybridization effect of donor and acceptor atoms on the cooperativity of C–H···N hydrogen bonds

2021 ◽  
Vol 27 (5) ◽  
Author(s):  
Mojtaba Ghaffari ◽  
Hamid Reza Masoodi ◽  
Sotoodeh Bagheri
Keyword(s):  
Hydrogen Bonds ◽  
Hybridization Effect ◽  
Donor And Acceptor ◽  
Theoretical Insight ◽  
Insight Into

scholarly journals Sensitivity of Intra- and Intermolecular Interactions of Benzo[h]quinoline from Car–Parrinello Molecular Dynamics and Electronic Structure Inspection

2021 ◽  
Vol 22 (10) ◽  
pp. 5220
Author(s):  
Jarosław J. Panek ◽  
Joanna Zasada ◽  
Bartłomiej M. Szyja ◽  
Beata Kizior ◽  
Aneta Jezierska
Keyword(s):  
Molecular Dynamics ◽  
Electronic Structure ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Quantum Effects ◽  
Potential Of Mean Force ◽  
Probability Density Distribution ◽  
Donor And Acceptor ◽  
Nuclear Quantum Effects ◽  
Vibrational Features

The O-H...N and O-H...O hydrogen bonds were investigated in 10-hydroxybenzo[h]quinoline (HBQ) and benzo[h]quinoline-2-methylresorcinol complex in vacuo, solvent and crystalline phases. The chosen systems contain analogous donor and acceptor moieties but differently coupled (intra- versus intermolecularly). Car–Parrinello molecular dynamics (CPMD) was employed to shed light onto principle components of interactions responsible for the self-assembly. It was applied to study the dynamics of the hydrogen bonds and vibrational features as well as to provide initial geometries for incorporation of quantum effects and electronic structure studies. The vibrational features were revealed using Fourier transformation of the autocorrelation function of atomic velocity and by inclusion of nuclear quantum effects on the O-H stretching solving vibrational Schrödinger equation a posteriori. The potential of mean force (Pmf) was computed for the whole trajectory to derive the probability density distribution and for the O-H stretching mode from the proton vibrational eigenfunctions and eigenvalues incorporating statistical sampling and nuclear quantum effects. The electronic structure changes of the benzo[h]quinoline-2-methylresorcinol dimer and trimers were studied based on Constrained Density Functional Theory (CDFT) whereas the Electron Localization Function (ELF) method was applied for all systems. It was found that the bridged proton is localized on the donor side in both investigated systems in vacuo. The crystalline phase simulations indicated bridged proton-sharing and transfer events in HBQ. These effects are even more pronounced when nuclear quantization is taken into account, and the quantized Pmf allows the proton to sample the acceptor area more efficiently. The CDFT indicated the charge depletion at the bridged proton for the analyzed dimer and trimers in solvent. The ELF analysis showed the presence of the isolated proton (a signature of the strongest hydrogen bonds) only in some parts of the HBQ crystal simulation. The collected data underline the importance of the intramolecular coupling between the donor and acceptor moieties.

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.

Studies on the Toxicity of Aromatic Hydrocarbons on Chorella Vulgaris by 3D-QSAR Using CoMFA and CoMSIA Methods

2012 ◽  
Vol 610-613 ◽  
pp. 3574-3579
Author(s):  
Cui Hua Wang ◽  
Sheng Long Yang ◽  
Chao Lu ◽  
Hong Xia Yu ◽  
Lian Shen Wang ◽  
...  
Keyword(s):  
Benzene Ring ◽  
Aromatic Hydrocarbons ◽  
Common Factor ◽  
3D Qsar ◽  
The Other ◽  
Contour Maps ◽  
Substituent Group ◽  
Donor And Acceptor ◽  
The Common ◽  
Insight Into

By using CoMFA and CoMSIA methods, the new quantitative structures of 25 aromatic hydrocarbons and the 96 hr-EC50 data with C. vulgaris have been investigated to obtain more detailed insight into the relationships between molecular structure and bioactivity. Compared to CoMFA (the average Q2LOO option =0.610), CoMSIA (the average Q2LOO =0.736) has the better results with robustness and stability. CoMSIA analysis using steric, electrostatic, hydrophobic, and H-bond donor and acceptor descriptors show H-bond donor is the common factor for influencing the toxicity, the steric and electrostatic descriptors are next and the hydrophobic descriptor was last. From the contour maps, the number of benzene ring is more crucial for the compound toxicity and the compounds with more benzene ring make toxicity increased. Under the same number of benzene ring, the kind of substituent group and the formed ability of H-bond are the other parameters to influencing the aromatic hydrocarbons toxicity.

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