scholarly journals Photoelectron Spectroscopic and ab Initio Computational Studies of the Anion, HThO–

2021 ◽  
Author(s):  
Mary Marshall ◽  
Zhaoguo Zhu ◽  
Junzi Liu ◽  
Lan Cheng ◽  
Kit H. Bowen
Keyword(s):  
Ab Initio ◽  
Computational Studies

Anomalous stabilizing and destabilizing effects in some cyclic π-electron systems

1993 ◽  
Vol 71 (8) ◽  
pp. 1123-1127 ◽  
Author(s):  
Peter Politzer ◽  
M. Edward Grice ◽  
Jane S. Murray ◽  
Jorge M. Seminario
Keyword(s):  
Ab Initio ◽  
Lone Pair ◽  
Electrostatic Potentials ◽  
Electron Delocalization ◽  
Isodesmic Reaction ◽  
Computational Studies ◽  
Electron Systems ◽  
Molecular Electrostatic Potentials ◽  
Lone Pairs

Ab initio computational studies have been carried out for three molecules that are commonly classed as antiaromatic: cyclobutadiene (1), 1,3-diazacyclobutadiene (7), and 1,4-dihydropyrazine (6). Their dinitro and diamino derivatives were also investigated. Stabilizing or destabilizing energetic effects were quantified by means of the isodesmic reaction procedure at the MP2/6-31G*//HF/3-21G level, and calculated molecular electrostatic potentials (HF/STO-5G//HF/3-21G) were used as a probe of electron delocalization. Our results do not show extensive delocalization in the π systems of any one of the three parent molecules. The destabilization found for 1 and 7 is attributed primarily to strain and to repulsion between the localized π electrons in the C=C and C=N bonds, respectively. However, 6 is significantly stabilized, presumably due to limited delocalization of the nitrogen lone pairs. NH2 groups are highly stabilizing, apparently because of lone pair delocalization. NO2 is neither uniformly stabilizing nor destabilizing.

[3,3] Sigmatropic Rearrangement of Some Fluorinated 1,5-Hexadienes

2002 ◽  
Vol 67 (10) ◽  
pp. 1517-1532 ◽  
Author(s):  
William R. Dolbier ◽  
Keith W. Palmer ◽  
Feng Tian ◽  
Piotr Fiedorow ◽  
Andrzej Zaganiaczyk ◽  
...  
Keyword(s):  
Experimental Data ◽  
Ab Initio ◽  
Transition States ◽  
Activation Parameters ◽  
Sigmatropic Rearrangement ◽  
Semiempirical Methods ◽  
Cope Rearrangement ◽  
Computational Studies ◽  
Stepwise Mechanism ◽  
Radical Intermediates

Fluorine atoms incorporated into 1,5-hexadiene molecule should influence the kinetic as well as the thermodynamic parameters of [3,3] sigmatropic rearrangement (Cope rearrangement). Within few decades is has been documented that this transformation proceeds in a concerted manner, rather than stepwise with some radical intermediates involved. Few new terminally fluorinated 1,5-hexadienes (compounds 3, 5A, 7, 9 and 5B) have been synthesized. The activation parameters of rearrangement have been determined and compared with those known for hydrocarbon analogues. While systems developing chair-like transition states (compounds 3 and 5) showed close similarity with hydrocarbon analogues (compound 1), those developing boat-like transition states (compounds 7, 9 and 5B) may proceed through radical stepwise mechanism. Computational studies of the transition states were carried out, showing that only ab initio methods (MP2 and especially DFT) can give approximate correlation with experimental data, whereas in the case of hydrocarbon analogues even simple semiempirical methods (AM1) were reliable enough to reproduce experimental results.

scholarly journals Experimental and ab initio computational studies on 5-(4-aminophenyl)-4-(3-methyl-3-phenylcyclobutyl)thiazol-2-amine

2008 ◽  
Author(s):  
Muharrem Dinçer ◽  
Namık Özdemir ◽  
Alaaddin Çukurovalı ◽  
Orhan Büyükgüngör
Keyword(s):  
Ab Initio ◽  
Computational Studies

Experimental and Ab Initio Computational Studies on 4-(Benzhydryloxy)phthalonitrile

2011 ◽  
Vol 537 (1) ◽  
pp. 111-127 ◽  
Author(s):  
Hanife Saraçoğlu ◽  
Feyizan Güntepe ◽  
Çiğdem Yüksektepe ◽  
Nezihe Çalışkan ◽  
Sinan Saydam
Keyword(s):  
Ab Initio ◽  
Computational Studies

scholarly journals Experimental and ab initio Computational Studies on Dimethyl-(4-{4-{3-methyl-3-phenyl-cyclobutyl)-thiazol-2-yl]-hydrazonomethyl}-phenyl)-amine

2010 ◽  
Vol 31 (12) ◽  
pp. 3553-3560 ◽  
Author(s):  
Cigdem Yuksektepe ◽  
Hanife Saracoglu ◽  
Nezihe Caliskan ◽  
Ibrahim Yilmaz ◽  
Alaaddin Cukurovali
Keyword(s):  
Ab Initio ◽  
Computational Studies

Positive electrospray ionization ion trap mass spectrometry and ab initio computational studies of the multi-pathway fragmentation of oxoaporphine alkaloids

2017 ◽  
Vol 418 ◽  
pp. 30-36 ◽  
Author(s):  
Felipe M.A. da Silva ◽  
Giovana A. Bataglion ◽  
Richardson A. de Almeida ◽  
Gabriel Heerdt ◽  
Iran L. Sousa ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Ab Initio ◽  
Electrospray Ionization ◽  
Ion Trap ◽  
Ion Trap Mass Spectrometry ◽  
Computational Studies

scholarly journals How ab initio Molecular Dynamics Can Change the Understanding on Transition Metal Catalysed Water Oxidation

2021 ◽  
Vol 75 (3) ◽  
pp. 195-201
Author(s):  
Mauro Schilling ◽  
Rangsiman Ketkaew ◽  
Sandra Luber
Keyword(s):  
Transition Metal ◽  
Ab Initio ◽  
Water Oxidation ◽  
Ab Initio Molecular Dynamics ◽  
Computational Studies ◽  
Chemical Complexity ◽  
Oxygen Oxygen ◽  
Wide Range ◽  
Solvent Environment

Artificial water splitting is a promising technology that allows the storage of renewable energy in the form of energy-rich compounds. This mini-review showcases how theoretical studies contribute to the under-standing of existing water oxidation catalysts (WOCs) as well as inspiring the development of novel WOCs. In order to understand the chemical complexity of transition metal complexes and their interaction with the solvent environment, the use of sophisticated simulation protocols is necessary. As an illustration, a family of ruthe- nium-based WOCs is presented which were investigated employing a wide range of forefront computational methods with emphasis on ab initiomolecular dynamic based approaches. In those studies a base assisted oxygen–oxygen bond formation was identified as the energetically most favourable reaction mechanism. By examining the role of local environmental effects at ambient temperature and the effect of modifications in the ligand framework, a comprehensible picture of the WOCs can be given, where the latter can serve as a guideline for further experimental and computational studies. In this mini-review, we provide a description of the methods, and the findings of our previous computational studies in compacted form, aimed at scientists with a theoretical as well as experimental background.

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