Structure électronique et réactivité des pyridyl-isothiocyanates. Étude quantique et photoélectronique

1986 ◽  
Vol 64 (8) ◽  
pp. 1467-1473 ◽  
Author(s):  
C. Guimon ◽  
G. Pfister-Guillouzo ◽  
D. Ilavsky ◽  
M. Marchalin ◽  
A. Martvon
Keyword(s):  
Molecular Orbital ◽  
Photoelectron Spectroscopy ◽  
Ultraviolet Photoelectron Spectroscopy ◽  
Molecular Orbital Calculations ◽  
Frontier Orbitals ◽  
Secondary Interactions ◽  
Made In ◽  
Structure Electronique

On the basis of molecular orbital calculations made in association with ultraviolet photoélectron spectroscopy (ups), it is demonstrated that the regioselectivity of the cycloadditions of pyridyl-2-isothiocyanate with 1,3-dipoles is directed by frontier orbitals. The different cycloadditions (4 + 2, 2 + 3, 2 + 2) vary with the overlap of these orbitals and this shows the importance of secondary interactions, namely the localization of the orbitals on the atoms adjacent to the bonds that are formed during the addition.

Gas-Phase Tautomerism in the Triazoles and Tetrazoles: A Study by Photoelectron Spectroscopy and ab Initio Molecular Orbital Calculations

1981 ◽  
Vol 36 (11) ◽  
pp. 1246-1252 ◽  
Author(s):  
Michael H. Palmer ◽  
Isobel Simpson ◽  
J. Ross Wheeler
Keyword(s):  
Ab Initio ◽  
Gas Phase ◽  
Molecular Orbital ◽  
Photoelectron Spectroscopy ◽  
Relative Stability ◽  
Photoelectron Spectra ◽  
Equilibrium Geometry ◽  
Molecular Orbital Calculations ◽  
Methyl Derivatives

The photoelectron spectra of the tautomeric 1,2,3,- and 1,2,4-triazole and 1,2,3,4-tetrazole systems have been compared with the corresponding N-methyl derivatives. The dominant tautomers in the gas phase have been identified as 2 H-1,2,3-triazole, 1 H-1,2,4-triazole and 2H-tetrazole.Full optimisation of the equilibrium geometry by ab initio molecular orbital methods leads to the same conclusions, for relative stability of the tautomers in each of the triazoles, but the calculations wrongly predict the tetrazole tautomerism.

Thermolysis of N-alkylated ethylenediamines: an ultraviolet photoelectron spectroscopy study

1986 ◽  
Vol 64 (11) ◽  
pp. 2175-2183 ◽  
Author(s):  
N. H. Werstiuk
Keyword(s):  
Molecular Orbital ◽  
Photoelectron Spectroscopy ◽  
The Other ◽  
Ultraviolet Photoelectron Spectroscopy ◽  
Spectroscopy Study ◽  
Efficient Route

Thermolyses of N,N,N′,N′-tetramethylethylenediamine (1a), N,N,N′,N′-tetraethylethylenediamine (1b) and sym-N,N′-dimethylethylenediamine (1c) at 760–825 °C have been studied by ultraviolet photoelectron spectroscopy. Although the corresponding N-alkylated aminomethylene radicals were not observed, this study establishes that thermolysis of 1a is an efficient route to N-methylenimine (3a); methane, ethane, and ethene are the other major products. Diamine 1b yields, besides ethane, ethene, and propane, heretofore unreported N-ethylmethylenimine (3b). Diamine 1c yields imine 3a and methylenimine (3c), as well as hydrogen, methane, ethane, and ethene. Molecular orbital eigenvalues of the imines are calculated using HAM/3, MNDO, HF/STO-3G, HF/3-21G, and HF/6-31G* methods.

The molecular energy levels of the azoles: A study by photoelectron spectroscopy and ab initio molecular orbital calculations

Tetrahedron ◽  
1973 ◽  
Vol 29 (14) ◽  
pp. 2173-2181 ◽  
Author(s):  
S. Cradock ◽  
R.H. Findlay ◽  
M.H. Palmer
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Photoelectron Spectroscopy ◽  
Energy Levels ◽  
Molecular Orbital Calculations

ChemInform Abstract: ELECTRONIC STRUCTURE OF DIAZOCYCLOPENTADIENE, A STUDY USING LOW AND HIGH ENERGY PHOTOELECTRON SPECTROSCOPY AND AB INITIO MOLECULAR ORBITAL CALCULATIONS

1974 ◽  
Vol 5 (29) ◽  
Author(s):  
LEON J. AARONS ◽  
JOSEPH A. CONNOR ◽  
IAN H. HILLIER ◽  
MARILYN SCHWARZ ◽  
D. ROBERT LLOYD
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Photoelectron Spectroscopy ◽  
High Energy ◽  
Molecular Orbital Calculations

ENERGY LEVELS OF TRIARYLMETHYL CARBONIUM IONS

1964 ◽  
Vol 42 (4) ◽  
pp. 810-817 ◽  
Author(s):  
E. K. Ng ◽  
F. C. Adam
Keyword(s):  
Molecular Orbital ◽  
Energy Levels ◽  
Fluorescence Band ◽  
Molecular Orbital Calculations ◽  
Structure Representation ◽  
Near Ultraviolet ◽  
Carbonium Ions ◽  
Visible Spectra ◽  
Made In

The near ultraviolet and visible spectra of the various phenyl-, p-biphenyl methyl carbonium ions have been investigated and the polarization of the absorptions relative to the fluorescence band have been determined. An assignment of the transitions is made, using as a basis simple molecular orbital calculations and the expectations based on the structure representation. These are compared to the assignments made in earlier researches. The calculated intensities are found to agree favorably with the observed values.

scholarly journals Study of Pentafluoroethane and its Thermal Decomposition Using UV Photoelectron Spectroscopy and Ab Initio Molecular Orbital Calculations

2010 ◽  
Vol 114 (4) ◽  
pp. 1816-1825 ◽  
Author(s):  
G. Copeland ◽  
E. P. F. Lee ◽  
J. M. Dyke ◽  
W. K. Chow ◽  
D. K. W. Mok ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Photoelectron Spectroscopy ◽  
Molecular Orbital Calculations ◽  
Uv Photoelectron Spectroscopy
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