Oxidative nitration reaction of antiaromatic 5,15-dioxaporphyrin

2020 ◽  
Vol 24 (01n03) ◽  
pp. 355-361 ◽  
Author(s):  
Akihide Nishiyama ◽  
Yuki Tanaka ◽  
Shigeki Mori ◽  
Hiroyuki Furuta ◽  
Soji Shimizu
Keyword(s):  
Electronic Structure ◽  
Reaction Mechanism ◽  
Blue Shift ◽  
Nics Calculations ◽  
Oxidative Nitration

Upon oxidation of 20[Formula: see text]-electron antiaromatic 5,15-dioxaporphyrin (DOP) using nitrosonium ions as oxidants, a tetrakis-[Formula: see text]-nitrated compound was formed instead of the expected 18[Formula: see text]-electron aromatic dication species via an oxidative nitration reaction mechanism. Compared with the original DOP, this tetranitro DOP product exhibited a blue shift of absorption and downfield shifts of the [Formula: see text]-pyrrolic proton signals. The unique antiaromatic electronic structure of the tetranitro DOP was disclosed experimentally by electrochemistry and theoretically by DFT and NICS calculations.

scholarly journals Study of Interaction between Tigecycline and Sulbactam

2019 ◽  
pp. 1-9
Author(s):  
Hakan Sezgin Sayiner ◽  
Fatma Genç ◽  
Fatma Kandemirli
Keyword(s):  
Electronic Structure ◽  
Reaction Mechanism ◽  
Peripheral Neuropathy ◽  
Drug Interactions ◽  
Reaction Mechanisms ◽  
Bond Formation ◽  
Therapeutic Drug ◽  
Energetic Condition ◽  
Biochemical Systems ◽  
Semi Empirical

Drug interactions can have desired, reduced or unwanted effects. The probability of interactions increases with the number of drugs taken. Side effects or therapeutic drug interactions can increase or decrease the effects of one or two drugs. Failure may result from clinically meaningful interactions. Clinicians rarely use foreseeable drug-drug interactions to produce the desired therapeutic effect. For example, when we consider two drugs each causing, peripheral neuropathy increases the likelihood of neuropathy occurrence. In this study geometry optimizations of tigecycline and sulbactam drugs and their combination have been carried out with the evaluation of B3LYP/6-311G (d, p), B3LYP/6-311G (2d, 2p) levels, and the reaction mechanism at semi empirical PM6, which was parameterized for biochemical systems and B3LYP/6-311G (d,p) levels. The main objective of the study is to understand the interaction ofsulbactam with tigecycline, to describe energetic condition of bond formation and electronic structure (orders of the broken and formed bonds). The reaction mechanisms of sulbactam with tigecycline have been studied as stepwise and concerted mechanisms using semi-empircal PM6 and B3LYP/6-311G (d,p) levels.

Luminescent Amorphous Silicon Layers

1997 ◽  
Vol 486 ◽  
Author(s):  
G. Allan ◽  
C. Delerue ◽  
M. Lannoo
Keyword(s):  
Electronic Structure ◽  
Amorphous Silicon ◽  
Radiative Recombination ◽  
Crystalline Silicon ◽  
Tight Binding ◽  
Blue Shift ◽  
Localized States ◽  
Structure Model ◽  
Radiative Recombination Rate ◽  
Tight Binding Approximation

AbstractThe electronic structure of amorphous silicon layers has been calculated within the empirical tight binding approximation using the Wooten-Winer-Weaire atomic structure model. We predict an important blue shift due to the confinement for layer thickness below 3 nm and we compare with crystalline silicon layers. The radiative recombination rate is enhanced by the disorder and the confinement but remains quite small. The comparison of our results with experimental results shows that the density of defects and localized states in the studied samples must be quite small.

Reactivity of Metal Carbenes with Olefins: Theoretical Insights on the Carbene Electronic Structure and Cyclopropanation Reaction Mechanism

2018 ◽  
Vol 122 (6) ◽  
pp. 1702-1712 ◽  
Author(s):  
E. de Brito Sá ◽  
A. Rimola ◽  
L. Rodríguez-Santiago ◽  
M. Sodupe ◽  
X. Solans-Monfort
Keyword(s):  
Electronic Structure ◽  
Reaction Mechanism ◽  
Metal Carbenes

CO2 conversion to methanol on Cu(i) oxide nanolayers and clusters: an electronic structure insight into the reaction mechanism

2015 ◽  
Vol 17 (16) ◽  
pp. 11088-11094 ◽  
Author(s):  
Ellie L. Uzunova ◽  
Nicola Seriani ◽  
Hans Mikosch
Keyword(s):  
Electronic Structure ◽  
Reaction Mechanism ◽  
Formic Acid ◽  
Co2 Conversion ◽  
Insight Into

The CO2 hydrogenation to methanol using dissociated water as the hydrogen source proceeds via stable carboxyl, formic acid and formaldehyde intermediates.

Propene oxidation catalysis and electronic structure of M55 particles (M = Pd or Rh): differences and similarities between Pd55 and Rh55

2020 ◽  
Vol 22 (21) ◽  
pp. 11783-11796
Author(s):  
Bo Zhu ◽  
Masahiro Ehara ◽  
Shigeyoshi Sakaki
Keyword(s):  
Electronic Structure ◽  
Catalytic Activity ◽  
Reaction Mechanism ◽  
Valence Band ◽  
Theoretical Study ◽  
Oxidation Catalysis ◽  
Propene Oxidation ◽  
Key Factor

This theoretical study elucidated the reaction mechanism of propene oxidation on Pd55 and Rh55 particles and disclosed that d valence band-top energy is a key factor in determining the catalytic activity.

Electronic structure and chemical conversions of peroxides. II. Mindo/3 calculations of reaction mechanism in noncatalytic epoxidation of olefins by hydroperoxides

1983 ◽  
Vol 23 (6) ◽  
pp. 830-837
Author(s):  
V. N. Kokorev ◽  
N. N. Vyshinskii ◽  
V. P. Maslennikov ◽  
I. A. Abronin ◽  
G. M Zhidomirov ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Reaction Mechanism ◽  
Epoxidation Of Olefins

Effect of Preparation Conditions on the Silicon L-Edge In Electrochemically Prepared Porous Silicon

1993 ◽  
Vol 298 ◽  
Author(s):  
T. Van Buuren ◽  
T. Tiedje ◽  
W. Weydanz
Keyword(s):  
Electronic Structure ◽  
High Resolution ◽  
Porous Silicon ◽  
Quantum Confinement ◽  
Light Exposure ◽  
Blue Shift ◽  
Bulk Silicon ◽  
Preparation Conditions ◽  
P Type ◽  
Confinement Model

AbstractHigh resolution measurements of the silicon L-edge absorption in electrochemically prepared porous silicon show that the absorption threshold is shifted to higher energy relative to bulk silicon, and that the shift is dependent on how the porous silicon is prepared. When the porous silicon is made from n-type material with light exposure, the blue shift increases logarithmically with the anodizing current. Porous silicon prepared by anodizing p-type silicon exhibits a blue shift in the L-edge which increases with the time spent in the HF solution after the anodizing potential is turned off. The data are consistent with the quantum confinement model for the electronic structure of porous silicon.

scholarly journals Elucidating the alkaline oxygen evolution reaction mechanism on platinum

2017 ◽  
Vol 5 (23) ◽  
pp. 11634-11643 ◽  
Author(s):  
M. Favaro ◽  
C. Valero-Vidal ◽  
J. Eichhorn ◽  
F. M. Toma ◽  
P. N. Ross ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Reaction Mechanism ◽  
Surface Chemistry ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Energy Production ◽  
Sustainable Energy ◽  
Liquid Interface ◽  
Solid Liquid Interface ◽  
Solid Liquid

Understanding the interplay between surface chemistry, electronic structure, and reaction mechanism of the catalyst at the electrified solid/liquid interface will enable the design of more efficient materials systems for sustainable energy production.

scholarly journals Metrology of the Real Nanoclusters: Structure and Optical Characteristics

2020 ◽  
pp. 54-58
Author(s):  
V. V. Kovalchuk ◽  
M. V. Smorzh
Keyword(s):  
Electronic Structure ◽  
Density Functional ◽  
Energy Gap ◽  
Theoretical Calculations ◽  
Blue Shift ◽  
Localized States ◽  
Optical Characteristics ◽  
Functional Theory ◽  
Free Carriers ◽  
Si Nanostructures

In this paper, we have discussed in detail the electronic structure and optical characteristics of the silicon nanoclusters. One of the main conclusions is that the comparison between theoretical calculations and experimental results are correct.  We shows the possibility of different radiative channels for the recombination in porous silicon. We now analyze the case of stronger disorder as obtained in amorphous silicon (a-Si). It raises extremely interesting problems related to the confinement-induced blue shift of the energy gap: (a) does it exist in nanoclusters of a-Si and is it comparable to what is obtained for c-Si; (b) what is the behavior of disorder-induced localized states in this regard. It has been often assumed that quantum confinement’s effects are small in a-Si nanostructures due to the short coherence length of free carriers in these materials. We will see that it is not true. We calculate the electronic structure of a-Si and a-Si:H spherical clusters using the parametrized density functional theory (PDFT) model [1]. The starting structure for the a-Si or a-Si: H nanoclusters is obtained by selecting the atoms belonging to the respective atoms unit cell. Due to the new boundary conditions the structure is no more in equilibrium and we have thus relaxed the atomic positions using a Keating potential.

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