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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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
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Triplet states of furan, thiophene, and pyrrole☆
TL;DR: In this article, low-lying triplet electronic states have been detected in furan, thiophene, and pyrrole by the method of variable-angle, electron-impact spectroscopy.
Journal ArticleDOI
Protonation processes and electronic spectra of histidine and related ions.
Zhijian Huang,Zijing Lin,Ce Song +2 more
TL;DR: The deprotonation and protonation of gaseous histidine both occur on the imidazole ring, explaining the versatile biofunctions of histidine in large biomolecules.
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Intramolecular [3 + 2]-cycloaddition reaction of push-pull dipoles across heteroaromatic pi-systems.
José M. Mejía-Oneto,Albert Padwa +1 more
TL;DR: Push-pull dipoles generated from the Rh(II)-catalyzed reaction of diazo imides containing tethered heteroaromatic rings undergo successful [3 + 2]-cycloaddition across the 2,3-pi-bond to provide novel pentacyclic compounds in good to excellent yields in a stereocontrolled fashion.
Journal ArticleDOI
Cycloaddition chemistry of 2-vinyl-substituted indoles and related heteroaromatic systems.
TL;DR: The intramolecular Diels-Alder cycloaddition reaction (IMDAF) of several N-phenylsulfonylindolyl-substituted furanyl carbamates containing a tethered pi-bond on the indole ring was examined as an approach to the iboga alkaloid catharanthine.
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Accessibility of the lowest quintet state of organic molecules through triplet-triplet annihilation; an indo ci study
Bernhard Dick,Bernhard Nickel +1 more
TL;DR: In this paper, it was shown that the triple-triplet annihilation of two metastable triplet states is sufficient for the creation of a particular excited state, provided that the sum of the excitation energies of the two triplets is sufficient to create the specific excited state.
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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