Photoelectron Spectroscopy of Heterocycles. Phenyloxiranes

1984 ◽  
Vol 39 (12) ◽  
pp. 1230-1234 ◽  
Author(s):  
H. Güsten ◽  
L. Klasinc ◽  
I. Novak ◽  
M. Sanjek
Keyword(s):  
Double Bond ◽  
Ethylene Oxide ◽  
Photoelectron Spectroscopy ◽  
Lone Pair ◽  
Photoelectron Spectra ◽  
Ionization Energies ◽  
Perpendicular Orientation ◽  
Trans Stilbene ◽  
Oxygen Lone Pair

The Hel photoelectron spectra of 2-phenyloxirane, 2,2-diphenyloxirane, trans-2.3-diphenyloxirane, 2,2,3-triphenyloxirane, and 2,2,3,3-tetraphenyloxirane are reported. Comparison with the spectra of ethylene oxide (oxirane), benzene, and the following phenylethenes-styrene (1). I,1-diphenylethene (2), cis-stilbene (3), trans-stilbene (4), triphenylethene (5), and tetraphenylethene (6) - allowed to assign the lower ionization energies of the phenyloxiranes. Splitting of the lowest energy benzene π-orbitals is qualitatively the same in both classes of compounds. Because of the perpendicular orientation of the oxygen lone-pair in comparison to the π-electrons of the ethylene double bond this splitting is considerably smaller in phenyloxiranes.

The Hei and HeH Photoelectron Spectra of [Fe*?3-C3H5(CO)3X] and [Fe^3-C4H7 (CO)3X] (X = Cl, Br, I) and [CoC3H5(CO)3]

1982 ◽  
Vol 37 (2) ◽  
pp. 179-185 ◽  
Author(s):  
Jaap N. Louwen ◽  
Jaap Hart ◽  
Derk J. Stufkens ◽  
Ad Oskam
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electronic Structures ◽  
Lone Pair ◽  
Iron Complexes ◽  
Photoelectron Spectra ◽  
Pair Type ◽  
Ionization Energies ◽  
Uv Photoelectron Spectroscopy

Abstract By means of UV photoelectron spectroscopy (UPS) the electronic structures of [Feη3.C3H5(CO)3X], [Feη3-(2-CH3C3H4)(CO)3X] (X = Cl, Br, I) and [Co(C3H5)(CO)3] have been studied. Detailed assignments are possible and surprisingly low ionization energies (as low as 8.19 eV) are found for iodine lone pair type Orbitals. From the spectra a large difference in π backbonding is found between the cobalt and iron complexes

A Discussion on photoelectron spectroscopy - Orderings of π and σ ionization potentials in carbocyclic and heterocyclic aromatic compounds

1970 ◽  
Vol 268 (1184) ◽  
pp. 131-140 ◽  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Aromatic Compounds ◽  
Lone Pair ◽  
Ionization Potentials ◽  
Photoelectron Spectra ◽  
Light Sources ◽  
Orbital Energies ◽  
Substituted Pyridines ◽  
Nitrogen Lone Pair ◽  
Electron Correlation Effects

Data on calculated orbital energies and experimentally measured ionization potentials of carbocyclic and heterocyclic aromatic compounds are compared and contrasted. The ordering or orbital energies and ionization potentials do not always seem to parallel one another, probably owing to either electron correlation effects, or to deviations from Koopman’s theorem. The effects on photoelectron spectra of using different light sources and analysers are discussed in relation to their bearing on the orbital orderings of aromatic compounds. The high resolution He 584 A. photoelectron spectrum of pyridine is shown to be open to two interpretations regarding the ordering of the ionization potentials of the π orbitals and the ‘nitrogen lone pair’ (n). One of the interpretations involves the three lowest pyridine ionization potentials being π (9.2 eV), π L (9.5 eV) and n (10.5 eV) whilst the other has the first three ionization potentials being the order π , n, π . The photoelectron spectra of substituted pyridines and diazines are discussed in the light of the two possible explanations for the pyridine spectrum.

Photoelectron Spectroscopy of Heterocycles. Fluorene Analogues

1978 ◽  
Vol 33 (9) ◽  
pp. 1006-1012 ◽  
Author(s):  
B. Ruščić ◽  
B. Kovač ◽  
L. Klasinc ◽  
H. Güsten
Keyword(s):  
Linear Correlation ◽  
Photoelectron Spectroscopy ◽  
Energy Levels ◽  
Photoelectron Spectra ◽  
Orbital Interaction ◽  
Ionization Energies

The He(I) photoelectron spectra of fluorene and its analogues, biphenyl, dibenzofuran, carbazole, dibenzothiophene, and phenanthrene were measured and analyzed. The assignment of the π-electron ionizations using orbital interaction and symmetry arguments for the constituent parts of the molecules indicates that the energy levels of the fluorene analogues can be reproduced within a few percent of error. A close linear correlation between the π-ionization energies and the eigenvalues of the corresponding HMO-orbitals is obtained as well.

Photoelectron Spectroscopic Studies of Piperidine and its N-Halo Derivatives

1979 ◽  
Vol 32 (3) ◽  
pp. 475 ◽  
Author(s):  
T Gan ◽  
JB Peel
Keyword(s):  
Lone Pair ◽  
Spectroscopic Studies ◽  
Resonance Interaction ◽  
Photoelectron Spectra ◽  
Ionization Energies ◽  
Nitrogen Lone Pair

The HeI photoelectron spectra of N-chloropiperidine and N-bromopiperidine have been measured and compared with that of piperidine. The ionization energies associated with the nitrogen lone- pair and halogen non-bonding electrons indicate that there is considerably less nN-nx resonance interaction than in the smaller halo amines. HeII studies show that the halogen character is localized in both the N-halopiperidines with most ionization energies showing simple inductive shifts resulting from halogenation.

The Photoelectron Spectra of the N-Chloro and N-Bromo Derivatives of Dimethylamine

1979 ◽  
Vol 32 (4) ◽  
pp. 719 ◽  
Author(s):  
F Carnovale ◽  
T Gan ◽  
JB Peel
Keyword(s):  
Energy Range ◽  
Molecular Orbital ◽  
Ionization Energy ◽  
Lone Pair ◽  
Photoelectron Spectra ◽  
Molecular Orbital Calculations ◽  
Ionization Energies ◽  
Resonance Effects ◽  
Derivatives Of ◽  
Lone Pair Interactions

The He I and He II spectra obtained for chlorodimethylamine (CH3)2NCl, and bromodimethylamine (CH3)2NBr, complete the study of the N-chloro and N-bromo derivatives of the small amines. The valence photoelectron spectra are interpreted with the aid of SPINDO molecular orbital calculations. Trends in the observed ionization energies for both series of small halo amines are described in terms of variations in inductive and resonance effects, the latter particularly concerning the nN/nx lone-pair interactions observed in the low ionization energy range.

The He(I) and X-ray photoelectron spectra of p-N,N-dimethylaminobenzalmalonitrile

1986 ◽  
Vol 64 (3) ◽  
pp. 528-531 ◽  
Author(s):  
A. Katrib ◽  
B.D. El-Issa ◽  
A. W. Potts
Keyword(s):  
Photoelectron Spectroscopy ◽  
Visible Spectrum ◽  
Energy Difference ◽  
Spectral Lines ◽  
Photoelectron Spectra ◽  
Semiempirical Methods ◽  
Ionization Energies ◽  
X Ray ◽  
Uv Visible ◽  
Uv Photoelectron Spectroscopy

The assignment of the four outermost ionization energies obtained by uv-photoelectron spectroscopy (UPS) of p-N,N-dimethylaminobenzalmalonitrile is given. The X-ray photoelectron spectroscopy of the N ls and C ls core levels are also discussed. Two "shake-up" lines were observed at the high binding energy side of the N ls spectral line. The energies of these spectral lines were found to correlate very well with the uv–visible spectrum. Also the energy difference of the two "shake-up" lines was found to be similar to the energy difference between the first and second ionization energies obtained by ups techniques. Only one "shake-up" line was observed in the case of C ls photoionization. Theoretical studies by semiempirical methods including HAM/3, MINDO/3, and extended Hückel are also discussed.

A Discussion on photoelectron spectroscopy - Molecular photoelectron spectroscopy

1970 ◽  
Vol 268 (1184) ◽  
pp. 7-31 ◽  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Energy Levels ◽  
Lone Pair ◽  
Electronic Energy ◽  
Photoelectron Spectra ◽  
Factors Affecting ◽  
Related Series ◽  
The Difference ◽  
Electronic Energy Levels ◽  
Vertical Ionization Energies

The principal features of helium 584 A photoelectron spectra of molecular vapours are outlined. Factors affecting the number of bands observed and their relation to the number of occupied electronic energy levels are discussed. The effect of the molecular translational velocity on the fundamental line widths attainable is considered and is shown to be significant though generally small compared with the much more common line broadening arising from ionic decomposition. Sharp lines are often to be associated with the presence of classical lone pairs but exceptions are noted. Structural effects in the lone pair ionization of chloro- and bromo-compounds are indicated. Some evidence is given for a correlation between the change in vibrational frequency produced upon ionization and the difference between adiabatic and vertical ionization energies. The use of such a correlation in the analysis of vibrational fine structure is exemplified by considering the examples of methylfluoride, 1,1-difluoroethylene, sulphur hexafluoride, ketene and pyrazine. A comparison between the p.e. spectra of butadiene, acrolein and glyoxal is used to indicate the utility of the method in creating energy level diagrams for related series of compounds.

Interactions between Oxygen Lone-Pair Orbitals and Double-Bond ?-Orbitals in ?,?-Unsaturated, Bicyclic Ketones; a PE-Spectroscopic Investigation

1987 ◽  
Vol 70 (6) ◽  
pp. 1540-1550 ◽  
Author(s):  
Pierre-Alain Carrupt ◽  
Raphy Gabioud ◽  
Albino Rubello ◽  
Pierre Vogel ◽  
Evi Honegger ◽  
...  
Keyword(s):  
Double Bond ◽  
Spectroscopic Investigation ◽  
Lone Pair ◽  
Bicyclic Ketones ◽  
Oxygen Lone Pair
Sign in / Sign up

Export Citation Format

Share Document