Showing papers by "Gaetano Granozzi published in 1982"
TL;DR: In this article, the molecular structure of the title compound has been determined from three-dimensional X-ray data, and the conformation of this molecular system is discussed also on the basis of the known structure of related compounds and previously reported theoretical results.
45 citations
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8 citations
TL;DR: In this article, the photoelectron spectra of hydantoin, 1-methylhydantoin and urazole are discussed and the spectra are assigned by comparison with the spectrum of succinimide and by INDO/S calculations.
8 citations
TL;DR: In this article, the electronic structure of (μ2-CO)[(η5-C5H5)Rh(CO)]2 is discussed on the basis of the gas-phase UV photoelectron spectrum and CNDO quantum-mechanical calculations.
5 citations
TL;DR: In this paper, the lowest unoccupied molecular orbital, which would assist the first electron transfer in the electrode reduction of the title compounds, is invariably of π type along the series, no σ*-π* crossover being predicted.
Abstract: Ab initio STO-3G calculations have been employed to study electronic properties associated with the lowest-lying virtual molecular orbitals of all the fluorinated benzenes. The results show that the lowest unoccupied molecular orbital, which would assist the first electron transfer in the electrode reduction of the title compounds, is invariably of π type along the series, no σ*—π* crossover being predicted. The perfluoro effect on the virtual molecular orbitals manifests itself by affecting the lowest σ* orbital significantly more than the π* orbitals. Orbital energies can be correlated with experimental vertical attachment energies. Following the nature and nodal characteristics of the lowest unoccupied molecular orbital, only a small fraction of the extra charge in the fluorobenzene anions resides on the CF bond. Possible implications between the present results and the polarographic reduction of halobenzenes are briefly mentioned.
3 citations
TL;DR: Ajb et al. as discussed by the authors reported the UV PE spectrum of N-vinylphthalimide in order to assess the extent of conjugation between an imidic and a vinyl group.
Abstract: A systematic investigation is in progress in our laboratories on the electronic structure and conformational flexibility of unsaturated N-substituted amides (Ajb et al., 1977, 1980, 1981, 1982a,b). Gas-phase UV photoelectron (PE) spectroscopy proved it a powerful tool in relating conformational and electronic effects since it can provide evidence on the degree of conjugation between 7r systems. This note reports the UV PE spectrum of N-vinylphthalimide in order to assess the extent of conjugation between an imidic and a vinyl group.
2 citations
TL;DR: In this paper, the spectral evidence indicates that there is a stronger Fe-butadiene interaction in the endo than in the exo isomer, and that perturbation of the Fe(CO)3 group on the uncomplexed butadiene is negligible.
2 citations
TL;DR: In this article, photo-electron spectra of some tetrakis(..beta..-diketonate)actinide complexes indicate that metal-ligand bonding is dominated by sigma-type overlaps.
1 citations
TL;DR: In this paper, excited photoelectron spectra of succinimide, maleimide and their N-methyl derivatives are presented and discussed, and the spectra are assigned by comparison with related molecules and analysis of the vibrational structure of the photo-electron bands.
Abstract: He(I) excited photoelectron spectra of succinimide, maleimide and theirN-methyl derivatives are presented and discussed. The spectra are assigned by comparison with related molecules and analysis of the vibrational structure of the photoelectron bands. The effects ofN-methyl substitution on both band position and fine structure are described.
TL;DR: In this article, the He(I) excited PE spectra of HOs 3 (μ 3 -L)(CO) 9 (L allenyl, allyl) and HOs 2 (μ 2 -vinyl) 10 are presented.
TL;DR: In this paper, the lowest unoccupied molecular orbital, which would assist the first electron transfer in the electrode reduction of the title compounds, is invariably of π type along the series, no σ*-π* crossover being predicted.
Abstract: Ab initio STO-3G calculations have been employed to study electronic properties associated with the lowest-lying virtual molecular orbitals of all the fluorinated benzenes. The results show that the lowest unoccupied molecular orbital, which would assist the first electron transfer in the electrode reduction of the title compounds, is invariably of π type along the series, no σ*—π* crossover being predicted. The perfluoro effect on the virtual molecular orbitals manifests itself by affecting the lowest σ* orbital significantly more than the π* orbitals. Orbital energies can be correlated with experimental vertical attachment energies. Following the nature and nodal characteristics of the lowest unoccupied molecular orbital, only a small fraction of the extra charge in the fluorobenzene anions resides on the CF bond. Possible implications between the present results and the polarographic reduction of halobenzenes are briefly mentioned.
TL;DR: In this paper, the electronic structure of 2-hydroxybenzylideneamine and 3-iminoprop-1-enol, a model system for intramolecularly hydrogen-bonded azomethine compounds, was investigated by means of ab initio calculations at STO-3G level.
Abstract: The electronic structure of 2-hydroxybenzylideneamine and of 3-iminoprop-1-enol, a model system for intramolecularly hydrogen-bonded azomethine compounds, was investigated by means of ab initio calculations at STO-3G level. The results show that the removal of a N2p non-bonding electron destabilizes the hydrogen-bonded structure. Ionization from the O2p-based molecular orbital gives an ion state which is stabilized by the hydrogen bonding, although the hydrogen-bonding energy is predicted to be smaller than in the neutral molecule.ΔSCF N2p and O2p ionization energies both increase on hydrogen-bond formation, thus being in agreement and apparently at variance, respectively, with known experimental trends. Relative molecular orbital energies are significantly dependent on the individual relaxation energy, which is calculated to be smaller in the bonded than in the non-bonded structure. The Mulliken population analysis shows that the decrease in the hydrogen-bonding energy in the O+2p ion, with respect to the neutral molecule, can be traced back to a decrease in the positive charge on the proton and in the reduced N⋯O electrostatic repulsion.The hydrogen-bonding destabilization in the N+2p ion can be associated with a reverse shift in the proton charge with respect to the neutral molecule and with O—H bond polarization and N⋯O coulombic repulsion in the non-bonded conformation being smaller than in the neutral molecule.
TL;DR: In this article, the photoelectron spectra of hydantoin, 1-methylhydantoin and urazole are discussed and the spectra are assigned by comparison with the spectrum of succinimide and by INDO/S calculations.
Abstract: He(I) excited photoelectron spectra of hydantoin, 1-methylhydantoin and urazole are presented and discussed. The spectra are assigned by comparison with the spectrum of succinimide and by INDO/S calculations. The electronic structure of the imido group of succinimide is not substantially perturbed by the replacement of one or two CH2 groups by NH groups. The HOMO is mainly localized on the additional nitrogen atoms in both the title compounds.