Journal ArticleDOI
Use of the CNDO Method in Spectroscopy. II. Five‐Membered Rings
Janet E. Del Bene,H. H. Jaffé +1 more
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In this paper, the modified CNDO method was used to calculate the electronic spectra of cyclopentadiene, the Cyclopentadienide ion, pyrrole, furan, pyrazole, imidazole, 2-pyrrolecarboxaldehyde, and furfural.Abstract:
The modified CNDO method previously reported has been used to calculate the electronic spectra of cyclopentadiene, the cyclopentadienide ion, pyrrole, furan, pyrazole, imidazole, 2‐pyrrolecarboxaldehyde, and furfural. In general, the results obtained agree quite well with experimental data. Because the CNDO method treats explicitly all σ and π valence electrons of a molecule, the results of the calculations are used to discuss some of the σ–π interactions which previously could not be treated. The calculations are successful in reflecting changes in the electronic spectra of compounds as a result of extending conjugation or addition of a substituent.read more
Citations
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Theoretical studies of positional isomers obtained by annelation of benzene and 5-membered ring heterocyclics containing nitrogen, oxygen, or sulphur☆
TL;DR: In this paper, the Pariser-Parr approach was used for the normal heteroaromatic molecules: indole, benzofuran, and thionaphthene.
Journal ArticleDOI
A kinetic study of the cracking, isomerization, and disproportionation of n-heptane on a chromium-exchanged Y zeolite
TL;DR: In this article, the kinetic rate constants for cracking, isomerization, and disproportionation of n-heptane over a CrHNaY (32% chromium exchanged) zeolite catalyst at 400, 450, and 470 °C have been calculated.
Journal ArticleDOI
The synthetic potential of pyridinium salt photochemistry.
Jiwen Zou,Patrick S. Mariano +1 more
TL;DR: In this Perspective, photocyclization reactions of pyridinium salts will be discussed, starting with the initial discovery, covering related processes of pyrylium salts, and extending to applications to the synthesis of natural and non-natural products of biomedical interest.
Journal ArticleDOI
The photochemical step of vision: The hydrogen bond and other associations
TL;DR: In this paper, it was shown on the basis of quantum chemical and spectroscopic arguments that through a consideration of the hydrogen bond and other intermolecular associations affecting the Schiff-base of retinal in the ground and excited states, a new assessment can be made of the conditions related to the photochemical primary step of vision.
Journal ArticleDOI
Selectivity in cycloadditions XII: the directive effect of enol ethers and thioenol ethers in cycloadditions of nitrile oxides
TL;DR: In this paper, the directing effect of oxygen and sulfur in cycloadditions of nitrile oxides to 2,3-dihydrofuran is evaluated at 2.8 and 1.1 Kcal mol -1 respectively.
References
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Journal ArticleDOI
Use of the CNDO Method in Spectroscopy. I. Benzene, Pyridine, and the Diazines
Janet E. Del Bene,H. H. Jaffé +1 more
TL;DR: In this article, the CNDO method was modified by substitution of semi-empirical Coulomb integrals similar to those used in the Pariser-Parr-Pople method, and by introducing a new empirical parameter κ to differentiate resonance integrals between σ orbitals from those between π orbitals.
Journal ArticleDOI
Theory and Applications of Ultraviolet Spectroscopy
Book
Basic principles of organic chemistry
TL;DR: In this article, the basic principles of organic chemistry are discussed and discussed in the context of basic principles in organic chemistry, including basic principles for organic chemistry and its application in the field of biology.
Journal ArticleDOI
Ground States of Conjugated Molecules. VII. Compounds Containing Nitrogen and Oxygen
TL;DR: The semi-empirical SCF-LCAO-MO procedures described in previous papers have now been extended to compounds containing heteroatoms, in particular nitrogen and oxygen as mentioned in this paper.
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