scholarly journals Mono BN-substituted analogues of naphthalene: a theoretical analysis of the effect of BN position on stability, aromaticity and frontier orbital energies

2018 ◽  
Vol 42 (15) ◽  
pp. 12968-12976 ◽  
Author(s):  
Milovan Stojanović ◽  
Marija Baranac-Stojanović

An insight into the electronic structure changes driven by CC → BN substitution in a naphthalene system has been given by quantum chemical calculations.

1997 ◽  
Vol 75 (12) ◽  
pp. 1851-1861 ◽  
Author(s):  
Heidi M. Muchall ◽  
Nick H. Werstiuk ◽  
Jiangong Ma ◽  
Thomas T. Tidwell ◽  
Kuangsen Sung

The He(I) photoelectron spectra of silylketenes (Me3Si)2C=C=O (1), Me5Si2CH=C=O (2), Me2Si(CH=C=O)2 (3), MeSi(CH=C=O)3 (4), (SiMe2CH=C=O)2 (5), and (CH2SiMe2CH=C=O)2 (6) have been recorded and their structures and orbital energies have been calculated by ab initio methods. Orbital energies for disilanes 2 and 5 are strongly dependent on a Si-Si-C-C torsional angle due to σ–π orbital interaction. Comparisons between experimental and simulated spectra show that 2 and 5 prefer conformations in which the Si—Si bond and ketene group(s) are approximately orthogonal (113° and 111°, respectively). Silylalkenes Me5Si2CH=CH2 (7) and (SiMe2CH=CH2)2 (8), which have been included in the computational study, show the same behavior as their corresponding silylketenes. Silylbis- and trisketenes 3–6 do not exhibit π–π interaction of any significance. For Si—Si containing compounds, the best agreement between experimental and computed data was obtained when Becke3LYP/6-31G*//HF/3-21G* was employed. Keywords: conformational behavior, electronic structure, photoelectron spectroscopy, quantum chemical calculations, silylketenes.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Olha Zhak ◽  
Oksana Karychort ◽  
Volodymyr Babizhetskyy ◽  
Chong Zheng

Abstract The title compound was prepared from the pure elements by sintering. The crystal structure was investigated by means of powder X-ray diffraction data. Ho5Pd19P12 exhibits the hexagonal Ho5Ni19P12-type structure with space group P 6 ‾ 2 m $P‾{6}2m$ , a = 13.1342(2), c = 3.9839(1) Å, R I = 0.060, R p = 0.080. The crystal structure can be described as a combination of two types of the structural units, [HoPd6P3] and [Ho3Pd10P6], respectively, mutually displaced by 1/2 along the crystallographic c axis. Quantum chemical calculations have been performed to analyze the electronic structure and provide deeper insight into the structure-property relationships. The results of the quantum chemical calculations indicate that the material features metallic bonding between Ho and Pd and covalent bonding between Pd and P.


2021 ◽  
Author(s):  
Soichi Shirai ◽  
Shinji Inagaki

Practical strategies for suppressing Si–C cleavage during the polycondensation of organosilanes were presented based on ab initio quantum chemical calculations of model compounds.


2016 ◽  
Vol 39 (3-4) ◽  
Author(s):  
Sandeep Pokharia ◽  
Rachana Joshi ◽  
Mamta Pokharia ◽  
Swatantra Kumar Yadav ◽  
Hirdyesh Mishra

AbstractThe quantum-chemical calculations based on density functional theory (DFT) have been performed on the diphenyltin(IV) derivative of glycyl-phenylalanine (H


1997 ◽  
Vol 488 ◽  
Author(s):  
J. L. Bredas ◽  
J. Cornil ◽  
D. Beljonne ◽  
D. A. Dos Santos ◽  
Z. Shuaiv ◽  
...  

AbstractIn this contribution, we investigate by means of correlated quantum-chemical calculations the influence of intermolecular interactions on the absorption and emission properties of conjugated chains. Various strategies are suggested to avoid a substantial decrease in fluorescence quantum yield in condensed media. Finally, the reliability of our theoretical approach is validated by showing the remarkable agreement obtained between the experimental data and the calculated optical properties of clusters formed by sexithienyl molecules.


2020 ◽  
Vol 22 (18) ◽  
pp. 9974-9981
Author(s):  
Manuel Hodecker ◽  
Alexis M. Driscoll ◽  
Uwe H. F. Bunz ◽  
Andreas Dreuw

Phenylethynylbenzenes exhibit a rich photochemistry changing dramatically with different ring orientation, as quantum-chemical calculations reveal for 1,4-bis(phenylethynyl)benzene showing different optical properties than its smaller relative tolan.


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