Journal ArticleDOI
Use of the CNDO Method in Spectroscopy. II. Five‐Membered Rings
Janet E. Del Bene,H. H. Jaffé +1 more
Reads0
Chats0
TLDR
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
More filters
Journal ArticleDOI
Two-photon spectroscopy of the biphenyl chromophore. The electronic excited states of biphenyl and fluorene below 50000 cm-1
Bernhard Dick,Georg Hohlneicher +1 more
TL;DR: In this article, the two-proton excitation spectra of biphenyl and fluorene in dilute solution have been measured up to 50000 cm −1.
Journal ArticleDOI
Properties of excited states of aromatic rings containing nitrogen
Karl Jug,Gerhard Hahn +1 more
Abstract: Quantum chemical calculations with the semiempirical molecular orbital (MO) method SINDO1 were performed on excited states of the following five- and six-membered heterocycles containing nitrogen: imidazol, pyrazol, pyridine, pyridazine, pyrimidine, pyrazine, and s-triazine. The geometries and adiabatic excitation energies of T1, S1, S2 were calculated. We also present charges, bond orders, and dipole moments. Consequences of these results for UV spectroscopic data are discussed.
Journal ArticleDOI
Triplet, radical anion and radical cation spectra of furocoumarins
TL;DR: Theoretical considerations using a CNDO/S method are able to explain the existence of these two different triplets, which might be considered as triplet exciplexes 3(FCδ‐. H2Oδ+) consistent with these triplet spectra being similar to the spectra of the corresponding radical anions.
Journal ArticleDOI
Magnetic Circular Dichroism of Nonaromatic Cyclic π-Electron Systems. 5.1 Biphenylene and Its Aza Analogues†
TL;DR: In this paper, the algebraic form of the perimeter model for nonaromatic cyclic π-electron systems developed in parts 1−4 of this series is used to analyze the previously reported magnetic circular dichroism (MCD) of biphenylene (1) and its aza analogues, to classify its excited states, and to relate them to those of other non-aromatic Cyclic systems, and the observed MCD signs are interpreted in terms of relative sizes of orbital energy differences and resulting configuration energy ordering.
Journal ArticleDOI
The Molecular Structure of Allenes and Ketenes II [1] Photoelectron Spectra, Absorption Spectra, and CNDO/S-Calculations of Phenyl and Methyl Substituted Allenes
W. Runge,W. Kosbahn,J. Kroner +2 more
TL;DR: In this paper, the conjugative and inductive effects of the phenyl and methyl substituents on the charge distribution of the allenic moiety, and conformational effects (isomerization energies, angle of twist) are discussed on the basis of experimental and calculated properties.
References
More filters
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.
Related Papers (5)
A Semi‐Empirical Theory of the Electronic Spectra and Electronic Structure of Complex Unsaturated Molecules. II
Rudolph Pariser,Robert G. Parr +1 more
Approximate Self‐Consistent Molecular Orbital Theory. III. CNDO Results for AB2 and AB3 Systems
J. A. Pople,G. A. Segal +1 more