ChemInform Abstract: BIS(BORANE)-CYCLENPHOSPHORANE: A STABLE ADDUCT IN WHICH TWO PHOSPHORUS(V)-BONDED NITROGEN ATOMS DISPLAY DONOR CHARACTER

1983 ◽  
Vol 14 (22) ◽  
Author(s):  
J.-M. DUPART ◽  
S. PACE ◽  
J. G. RIESS
Keyword(s):  
Stable Adduct ◽  
Donor Character

COMPLEX DONORS IN NITROGEN-DOPED DIAMOND

2004 ◽  
Vol 03 (04n05) ◽  
pp. 455-461
Author(s):  
YING DAI ◽  
ANYI LI ◽  
YING ZHANG ◽  
SHENGHAO HAN
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Shallow Donor ◽  
Dangling Bond ◽  
Single Vacancy ◽  
Functional Theory ◽  
Nitrogen Doped ◽  
Ultrananocrystalline Diamond ◽  
Cluster Methods ◽  
Donor Character

Several Nitrogen (N)-hydrogen(H), N-dangling bond (DB) and N-single vacancy (V) complexes as the possible donor centers in diamond have been investigated using both supercell and cluster methods within the frame of density functional theory. We have found that the H—N—N—H complex exhibits shallower donor character than that of the N—H—N center discussed by Miyazaki et al.1 and it is one of the possible effective shallow donor centers in crystalline diamond. We conclude that the N—V related complex demonstrates a character of shallow donors and it should be one of the possible donor centers for the ultrananocrystalline diamond (UNCD) films, which are responsible for the n-type high conductivity of these films.

scholarly journals Equilibrium constants and protonation site for N-methylbenzenesulfonamides

2011 ◽  
Vol 7 ◽  
pp. 1732-1738 ◽  
Author(s):  
José A Moreira ◽  
Ana M Rosa da Costa ◽  
Luis García-Río ◽  
Márcia Pessêgo
Keyword(s):  
Sulfuric Acid ◽  
Oxygen Atom ◽  
Electron Donor ◽  
Equilibrium Constants ◽  
Acidity Constants ◽  
Protonation Site ◽  
Protonation Equilibria ◽  
Vis Spectroscopy ◽  
Donor Character ◽  
Solvation Parameter

The protonation equilibria of four substituted N-methylbenzenesulfonamides, X-MBS: X = 4-MeO (3a), 4-Me (3b), 4-Cl (3c) and 4-NO2 (3d), in aqueous sulfuric acid were studied at 25 °C by UV–vis spectroscopy. As expected, the values for the acidity constants are highly dependent on the electron-donor character of the substituent (the pK BH+ values are −3.5 ± 0.2, −4.2 ± 0.2, −5.2 ± 0.3 and −6.0 ± 0.3 for 3a, 3b, 3c and 3d, respectively). The solvation parameter m* is always higher than 0.5 and points to a decrease in the importance of solvation on the cation stabilization as the electron-donor character of the substituent increases. Hammett plots of the equilibrium constants showed a better correlation with the σ+ substituent parameter than with σ, which indicates that the initial protonation site is the oxygen atom of the sulfonyl group.

Determination of an effect of 3-chlorophenol on hydroxyl radical generation during ozonation through kinetic study in the power law type

2004 ◽  
Vol 4 (5-6) ◽  
pp. 305-311
Author(s):  
Y.-H. Han ◽  
I. Koshiishi ◽  
H. Utsumi
Keyword(s):  
Power Law ◽  
Ozone Decomposition ◽  
Oh Radical ◽  
Catalytic Intermediates ◽  
Stable Adduct ◽  
Solution Proceeds ◽  
Radical Generation ◽  
Power Law Equation ◽  
The Relationship

Ozone decomposition in aqueous solution proceeds through a radical type chain mechanism. These reactions involve the very reactive and catalytic intermediates hydroxyl (OH) radical, O2− radical, HO2 radical, OH−, H2O2, etc. OH radical is proposed as an important factor in the ozonation of water. In the previous study, generation of OH radical in the ozonation of water containing 3-chlorophenol was mathematically evaluated. In this study, we estimated the kinetic equation for the effect of 3-chlorophenol on OH radical generation during ozonation using the power law equation, in order to analyze it more correctly. The OH radical was trapped with a 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a stable adduct, DMPO-OH. The relationship between the ozone concentration, 3-chlorophenol content, and the initial velocity (ν0) of DMPO-OH generation was analyzed mathematically, and the following equation was obtained: ν0 (10−6 M/s)=(1.58×10−5)×[3-chlorophenol (10−6 M)]×[ozone (10−6 M)]2.40+(3.09×10−5)×[ozone (10−6 M)]1.72. The equation fitted very well with the experimental results, and square of the correlation coefficient was larger than 0.9.

Simulation of Vacancy Pairs in GaN Using Tight-Binding Molecular Dynamics

1997 ◽  
Vol 482 ◽  
Author(s):  
Derrick E. Boucher ◽  
Zoltán A. Gál ◽  
Gary G. DeLeo ◽  
W. Beall Fowler
Keyword(s):  
Molecular Dynamics ◽  
Electronic Structure ◽  
Total Energy ◽  
Formation Energy ◽  
Tight Binding ◽  
Md Simulations ◽  
Shallow Donor ◽  
Shallow Acceptor ◽  
Structure Geometry ◽  
Donor Character

AbstractThe electronic structure, geometry and energetics of Ga vacancy pairs and N vacancy pairs in both wurtzite and zincblende GaN are investigated via molecular dynamics (MD) simulations using an empirical tight-binding (TB) model with total energy capabilities and supercells containing up to 216 atoms. Our calculations suggest that, by pairing, N vacancies, which in isolation act as shallow donors, can lower their collective formation energy by about 5 eV. In doing so, however, these N vacancies lose their shallow-donor character as the lattice relaxes in response to this aggregation. Contrasting with the N vacancies, the Ga vacancies are found to retain their isolated shallow acceptor behavior and do not gain significant energy upon aggregation. The possible implications for larger aggregate defects are discussed.

An experimental and theoretical approach to the study of the properties of parabanic acid and related compounds: synthesis and crystal structure of diethylimidazolidine-2-selone-4,5-dione

2000 ◽  
Vol 78 (9) ◽  
pp. 1147-1157
Author(s):  
Massimiliano Arca ◽  
Francesco Demartin ◽  
Francesco A Devillanova ◽  
Francesco Isaia ◽  
Francesco Lelj ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Dft Calculations ◽  
Electronic Structures ◽  
Frontier Orbitals ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Related Compounds ◽  
Donor Character ◽  
Ft Raman

The syntheses of the first examples of selenoparabanic acid derivatives (dialkylimidazolidine-2-selone-4,5-dione, 3eR R = Me, Et, Bu) are presented along with the X-ray crystal structure determination of 3eEt. To gain an insight in the properties of parabanic acid derivatives on the basis of their electronic structures, we report the results of comparative hybrid-DFT calculations performed on parabanic, thioparabanic, and selenoparabanic acids (3aH, 3bH, and 3eH) and on their N,N' -dimethyl derivatives (3aMe, 3bMe, and 3eMe). Calculations show that the different nature of the frontier orbitals of 3aR compared to those of 3bR and 3eR, might account for the different reactivities of these compounds. Moreover, the weak donor character of 3bR and 3eR towards molecular di-iodine, estimated by FT-Raman measurements is in agreement with the calculated NBO-charge distribution.Key words: selenation, selenoparabanic derivatives, crystal structure, DFT calculations.

Fabrication of the stable adduct CdS/CTAB/Clay with sandwich-like nanostructures

2006 ◽  
Vol 8 (5) ◽  
pp. 661-668 ◽  
Author(s):  
Xuchu Ma ◽  
Fen Xu ◽  
Liyong Chen ◽  
Yi Du ◽  
Zude Zhang
Keyword(s):  
Stable Adduct

Mössbauer study of the donor character of oxygen in Si−O bonds

1975 ◽  
Vol 25 (2) ◽  
pp. 275-282 ◽  
Author(s):  
B. Csákvári ◽  
É. Csákvári ◽  
P. Gömöry ◽  
A. Vértes
Keyword(s):  
Mössbauer Study ◽  
Donor Character

scholarly journals Estimation of Bite Angle Effect on the Electronic Structure of Cobalt-Phosphine Complexes: A QTAIM Study

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Tamara Papp ◽  
László Kollár ◽  
Tamás Kégl
Keyword(s):  
Electronic Structure ◽  
Simple Model ◽  
Dft Calculations ◽  
Model Compound ◽  
Carbonyl Ligand ◽  
Reaction Conditions ◽  
Phosphine Complexes ◽  
Bite Angle ◽  
Angle Effect ◽  
Donor Character

The influence of bite angle in bisphosphine complexes has been modeled by DFT calculations employing the simple model compound HCo(CO)(PP) (PP = Xantphos or two monophosphine ligands). The increase of the bite angle increases the strength of the H–Co bond, whereas the C–O bond in the carbonyl ligand is weakened revealing an increase also in the donor character. The model compound cis-[HCo(CO)(PPh3)2] shows a flexibility both in terms of energy, and in terms of electronic structure upon the change of the P-Co-P angle, which can be a sign of the flexibility of PPh3 ligands in real reaction conditions.

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