scholarly journals Front Cover: On the Stability of Disubstituted Cyclobutenes - A Computational Study (Eur. J. Org. Chem. 2-3/2019)

2018 ◽  
Vol 2019 (2-3) ◽  
pp. 228-228
Author(s):  
Boris Maryasin ◽  
Nuno Maulide
2021 ◽  
Vol 21 (4) ◽  
pp. 2419-2426
Author(s):  
Csaba L. Nagy ◽  
Katalin Nagy

Fullerenes that violate the isolated pentagon rule are too reactive and were obtained only as endoor exohedral derivatives. Density functional theory using the B3LYP hybrid density functional was applied to investigate the electronic and structural properties of the ten smallest tetrahedral (Td or T point group) fullerenes containing four directly fused pentagon-triples. The influence of nitrogen doping and exohedral hydrogenation of the four reactive sites was also analyzed. Nucleus independent chemical shifts values computed using B3LYP/6-31G(d) are used as global and local aromaticity probe. The global strain energy is evaluated in terms of the pyramidalization (POAV) angle. The results show that the stability increases with the elimination of the energetically unfavorable strain.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Saleh S. Alarfaji ◽  
Sajjad Hussain ◽  
Abdullah G. Al-Sehemi ◽  
Shabbir Muhammad ◽  
Islam Ullah Khan ◽  
...  

Abstract In the present study, copper (II) complex of 4, 4′-di-tert-butyl-2,2′-bipyridine [Cu (C18H24N2) (NO3)2], 1 is investigated through its synthesis and characterization using elemental analysis technique, infra-red spectroscopy, and single-crystal analysis. The compound 1 crystallizes in orthorhombic space group P212121. The copper atom in the mononuclear complex is hexa coordinated through two nitrogen and four oxygen atoms from bipyridine ligand and nitrate ligands. The thermal analysis depicts the stability of the entitled compound up to 170 °C, and the decomposition takes place in different steps between 170 and 1000 °C. Furthermore, quantum chemical techniques are used to study optoelectronic, nonlinear optical, and therapeutic bioactivity. The values of isotropic and anisotropic linear polarizabilities of compound 1 are calculated as 41.65 × 10−24 and 23.02 × 10−24 esu, respectively. Likewise, the static hyperpolarizability is calculated as 47.92 × 10−36 esu using M06 functional compared with para-nitroaniline (p-NA) and found several times larger than p-NA. Furthermore, the antiviral potential of compound 1 is studied using molecular docking technique where intermolecular interactions are checked between the entitled compound and two crucial proteins of SARS-CoV-2 (COVID-19). Our investigation indicated that compound 1 interacts more vigorously to spike protein than main protease (MPro) due to its better binding energy of −9.60 kcal/mol compared with −9.10 kcal/mol of MPro. Our current study anticipated that the above-entitled coordination complexes could be potential candidates for optoelectronic properties and their biological activity.


2021 ◽  
Author(s):  
Pushparaj Loganathan ◽  
Renjith S. Pillai ◽  
Velusamy Jeevananthan ◽  
Ezhumalai David ◽  
Nallasamy Palanisami ◽  
...  

Discrete and oligomeric organotin DDSQs have been synthesized and characterized, both experimentally and through computational study. The stability of these compounds remains intrigued with the organization of their structure in the crystal lattice.


2021 ◽  
Vol 23 (36) ◽  
pp. 20553-20559
Author(s):  
Han Wang ◽  
Xiao Wang ◽  
Da Li

We performed a systematic study on the defects in PbI2 of both 1T and 1H phases by DFT calculations. The stability at the neutral and charged states was calculated. The impact of the defects on the electronic properties was also discussed.


2016 ◽  
Vol 22 (43) ◽  
pp. 15501-15507
Author(s):  
Beatrice Fantini ◽  
Francesco Faglioni

ChemCatChem ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 2115-2115
Author(s):  
Michael Dierks ◽  
Zhengwen Cao ◽  
Jinesh C. Manayil ◽  
Jeganathan Akilavasan ◽  
Karen Wilson ◽  
...  
Keyword(s):  

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Juan D. Colmenares ◽  
Omar D. López ◽  
Sergio Preidikman

This paper presents the simulation of a two-rotor aircraft in different geometric configurations during hover flight. The analysis was performed using an implementation of the unsteady vortex-lattice method (UVLM). A description of the UVLM is presented as well as the techniques used to enhance the stability of results for rotors in hover flight. The model is validated for an isolated rotor in hover, comparing numerical results to experimental data (high-Reynolds, low-Mach conditions). Results show that an exclusion of the root vortex generates a more stable wake, without affecting results. Results for the two-rotor aircraft show an important influence of the number of blades on the vertical thrust. Furthermore, the geometric configuration has a considerable influence on the pitching moment.


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