نتایج جستجو برای: logp and electron delocalization

تعداد نتایج: 16879907  

2008
Cai-Hong Zhan Shu-Guang Zhang Yun-Long Feng

The title compound, C(9)H(8)N(4)O(3)S, shows a layer structure constructed from inter-molecular O-H⋯O and O-H⋯N hydrogen bonds. Inter-atomic distances suggest that extensive, but not uniform, π-electron delocalization is present in the tetra-zole rings and extends over the exocyclic C-S bond.

2012
Agata Martyniak Pawel Lipkowski Noel Boens Aleksander Filarowski

The ketoenamine-enolimine tautometic equilibrium has been studied by the analysis of aromaticity and electron-topological parameters. The influence of substituents on the energy of the transition state and of the tautomeric forms has been investigated for different positions of chelate chain. The quantum theory of atoms in molecules method (QTAIM) has been applied to study changes in the electr...

Journal: :Acta crystallographica. Section C, Crystal structure communications 2004
Juana E Pérez-Vargas Francisco J Martínez-Martínez Itzia I Padilla-Martínez Herbert Höpfl Efrén V García-Báez

The title compound, C16H19NO5, crystallizes as a centrosymmetric dimer through strong O-H...O hydrogen-bonding interactions between the hydroxyphenyl and morpholinocarbonyl groups. The morpholinocarbonyl group is almost perpendicular to the propenoate moiety. Electron delocalization in the N-C(=O) fragment leads to the formation of hydrogen-bonded S(5) ring motifs through C-H...O interactions.

Journal: :international journal of environmental research 2011
d.x. jiang y. li j. li g.x. wang

the purpose of this work is to develop robust and interpretable quantitative structure”activity relationship (qsar) models for assessing the aquatic toxicity of phenols using a combined set of descriptors encompassing the logp and recently developed variables (monconn-z variables). the used dataset consists of 250 chemicals with toxicity data to the ciliate tetrahymena pyriformis. for each com...

Journal: :Micron 2012
R F Egerton S Lazar M Libera

We present and discuss measurements of electron-irradiation damage in polystyrene and other polymers, based on fading of the 7-eV energy-loss peak. These measurements suggest a large increase in characteristic dose as the electron-beam diameter is reduced from 1 μm to below 1 nm. This finding is discussed in terms of secondary-electron production and delocalization of the inelastic scattering, ...

Journal: :The Journal of chemical physics 2008
Lukasz Cwiklik Udo Buck Waldemar Kulig Piotr Kubisiak Pavel Jungwirth

Ab initio molecular dynamics simulations modeling low-energy collisions of a sodium atom with a cluster with more than 30 water molecules are presented. We follow the dynamics of the atom-cluster interaction and the delocalization of the valence electron of sodium together with the changes in the electron binding energy. This electron tends to be shared by the nascent sodium cation and the wate...

2013
Ewa D. Raczyńska Beata Kamińska

Quantum-chemical calculations were performed for all possible nine neutral tautomers of purine and their oxidized and reduced forms in water {PCM//DFT(B3LYP)/6-311+G(d,p)} and compared to those in the gas phase {DFT(B3LYP)/6-311+G(d,p)}. PCM hydration influences geometries, π-electron delocalization, and relative energies of purine tautomers in different ways. Generally, the harmonic oscillator...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه گیلان - دانشکده فنی 1393

asymmetric membranes are widely used in many industrial membrane separation processes. the major advantage of membrane filtration over the conventional process is its ability to remove a wider spectrum of particles without using any chemicals. hollow fiber configuration offer many advantages over flat-sheet or tubular membranes. the spinning process of hollow fiber may look simple, yet it is te...

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشگاه مواد و انرژی - پژوهشکده سرامیک 1392

thermal barrier coatings (tbcs) are used to provide thermal insulation to the hot section components of gas turbines in order to enhance the operating temperature and turbine efficiency. hot corrosion and thermal shocks are the main destructive factors in tbcs which comes as a result of oxygen and molten salt diffusion into the coating. in this thesis atmospheric plasma spraying was used to dep...

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