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.

Photoelectron spectroscopic studies of the Propyl- and Allyl-substituted amines

1977 ◽  
Vol 30 (12) ◽  
pp. 2571 ◽  
Author(s):  
JB Peel ◽  
GD Willett
Keyword(s):  
Ionization Potential ◽  
Density Of States ◽  
Lone Pair ◽  
Spectroscopic Studies ◽  
Photoelectron Spectra ◽  
Sum Rule ◽  
Nitrogen Lone Pair ◽  
Lone Pair Electrons ◽  
First Ionization Potential

The HeI (21.22 eV) photoelectron spectra of the mono-, di- and tri- propyl- and allyl-substituted amines are reported up to 21 eV. The assignments are based on SPINDO calculations, on the comparison with other related molecules, a density of states analysis and a sum rule treatment. The first ionization potential band in each of the spectra is assigned to the nitrogen lone-pair electrons and for the allylamines the second band is assigned to the ethylenic π-bond electrons.

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. 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

scholarly journals Ionization potentials of nitriles — Photoelectron spectra of succinonitrile and glutaronitrile

2006 ◽  
Vol 84 (9) ◽  
pp. 1124-1131 ◽  
Author(s):  
Heidi M Muchall ◽  
Nick H Werstiuk
Keyword(s):  
Energy Region ◽  
Photoelectron Spectrum ◽  
Lone Pair ◽  
Low Energy ◽  
Ionization Potentials ◽  
Photoelectron Spectra ◽  
Proton Affinities ◽  
Nitrogen Lone Pair ◽  
D Model ◽  
Highest Occupied Molecular Orbitals

The He(I) photoelectron spectra of succinonitrile (1) and glutaronitrile (2), both with extensive overlap of ionization bands in the low-energy region, are reported. To assign ionizations, we studied the conformational behaviour and resulting ionization energy dependence of 1 and 2 computationally with the B3LYP/6-31+G(d) model chemistry based on the fact that it reliably reproduces the ionization potentials of eleven mono- and di-nitriles, both saturated and unsaturated. The correlation of proton affinities with observed ionization potentials of 1, 2, and malononitrile establishes the orbital sequence of four C≡N π orbitals followed by two nitrogen lone pair orbitals as the highest occupied molecular orbitals for all three compounds.Key words: photoelectron spectrum, ionization potential, conformational dependence, nitrile, DFT.

The photoelectron spectra of some molecules containing the C≡N group

1970 ◽  
Vol 317 (1529) ◽  
pp. 187-198 ◽  
Keyword(s):  
Cyanogen Bromide ◽  
Lone Pair ◽  
Vibrational Structure ◽  
Ionization Potentials ◽  
Photoelectron Spectra ◽  
Spin Orbit Coupling ◽  
Ethyl Vinyl ◽  
Cyanogen Chloride ◽  
Nitrogen Lone Pair ◽  
Cyanogen Iodide

The photoelectron spectra of a number of molecules containing the C≡N group have been measured over the range 6 to 21 eV. For cyanogen chloride, cyanogen bromide and cyanogen iodide, ionization potentials have been determined and assigned to particular molecular orbitals on the basis of the vibrations coupled with the ionization processes, and of the splitting due to spin-orbit coupling. Differences in these features among the three compounds have been discussed in terms of the delocalization of electrons in these molecules. From the spectra of methyl, ethyl, vinyl and allyl cyanides, potentials have been determined for ionization from the C=C π, C≡N π and nitrogen lone pair orbitals, and other higher ionization potentials have been determined but not assigned explicitly. A number of ionization potentials have been determined for mono-, di-, and tri-chloro-methyl cyanides, but absence of accompanying vibrational structure and the additional complexity caused by the levels derived from 3p electrons in the chlorine atoms make specific assignments impossible.

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.

Electrochemical and Raman spectroscopic studies of pyrazine adsorption at the Au(210) electrode surface

1997 ◽  
Vol 75 (11) ◽  
pp. 1694-1702 ◽  
Author(s):  
Anna Lannelli ◽  
Jacek Lipkowski ◽  
Alexandre G. Brolo ◽  
Donald E. Irish
Keyword(s):  
Electrode Surface ◽  
Lone Pair ◽  
Spectroscopic Studies ◽  
Vertical Orientation ◽  
Raman Spectroscopic ◽  
Gibbs Energies ◽  
Electrode Potentials ◽  
Surface Enhanced Raman ◽  
Nitrogen Lone Pair ◽  
Enhanced Raman Scattering

Chronocoulometry and Raman spectroscopy have been applied to study pyrazine adsorption at the Au(210) electrode surface. The adsorption isotherms, Gibbs energies of adsorption, and the electrosorption valency for pyrazine adsorption at the Au(210) electrode surface have been determined. Surface-enhanced Raman Scattering (SERS) spectra of pyrazine adsorbed on an "unroughened" Au(210) electrode surface have been obtained for the first time. The thermodynamic data and the SERS spectra indicate that pyrazine adsorbs on the Au(210) electrode via the nitrogen lone pair (N-bonded configuration) over the whole range of electrode potentials investigated. Consequently, the pyrazine molecule assumes only the vertical orientation at this surface of gold. The adsorption of pyrazine at the Au(210) and Au(111) surfaces is compared and the influence of the surface crystallography on the adsorption of this molecule at gold electrodes is discussed. Keywords: adsorption at Au(210), pyrazine, SERS, chronocoulometry.

13C NMR spectroscopic studies of C-nitroso compounds. The orientation of the nitroso group in substituted nitrosobenzenes

1994 ◽  
Vol 72 (3) ◽  
pp. 514-518 ◽  
Author(s):  
Brian G. Gowenlock ◽  
Mailer Cameron ◽  
Alan S.F. Boyd ◽  
Baheeja M. Al-Tahou ◽  
Paul McKenna
Keyword(s):  
Solid State ◽  
Functional Group ◽  
Chemical Shifts ◽  
Lone Pair ◽  
Spectroscopic Studies ◽  
Nitroso Compounds ◽  
Nitroso Group ◽  
Nitrogen Lone Pair ◽  
Electronic Character ◽  
Ortho Substituent

The carbon-13 chemical shifts of several substituted nitrosobenzenes are reported. It is shown that the NO group can be orientated to lie in the plane of the ring when constrained either by a bulky ortho substituent or in the solid state. In the presence of 2,6-di-tert-butyl substituents the NO group is twisted into orthogonality with the ring. The changes in the 13C chemical shifts are larger for the NO group than for other functional groups. It is suggested that these effects are a consequence of the electronic character of the NO group and that the nitrogen lone pair of electrons is of fundamental importance in producing these unique effects. The dimeric nitroso functional group does not display these properties.

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