The Ultraviolet Absorption Spectra of the Acridone Alkaloids. I. Compounds containing the Acridone Nucleus

1950 ◽  
Vol 3 (4) ◽  
pp. 593 ◽  
Author(s):  
RD Brown ◽  
FN Lahey
Keyword(s):  
Electron Density ◽  
Absorption Spectra ◽  
Ultraviolet Absorption ◽  
Absorption Bands ◽  
Ultraviolet Spectra ◽  
Spectral Changes ◽  
Acridone Alkaloids

The ultraviolet spectra of the acridone alkaloids and some derivatives have been studied. The various bands in the spectra of these compounds are interpreted by starting with theoretical treatments of the spectrum of anthracene and tracing spectral changes through acridine and phenazine to acridone. An interesting relation between the π-electron density of a given position in the acridone ring and the shift in wavelength of absorption bands due to an alkoxyl derivative is noted and the spectra of the alkaloids are shown to comply with this relationship. Compounds containing a 4-hydroxy-10-methylacridone structure are found to have unusual spectra and a possible explanation of this is proposed.

The Ultraviolet Absorption Spectra of the Acridone Alkaloids. II. Compounds related to 4-Quinolone

1950 ◽  
Vol 3 (4) ◽  
pp. 615 ◽  
Author(s):  
RD Brown ◽  
FN Lahey
Keyword(s):  
Absorption Spectra ◽  
Degradation Products ◽  
Ultraviolet Absorption ◽  
Ultraviolet Spectra ◽  
Acridone Alkaloids ◽  
Qualitative Discussion

A qualitative discussion, based mainly upon the MO approximation, is presented for the ultraviolet spectra of naphthalene, quinolone, and some degradation products of the acridone alkaloids related to 4-quinolone.

VISIBLE AND ULTRAVIOLET ABSORPTION SPECTRA OF RHODIUM(III) IN FUSED ALKALI CHLORIDES AND NITRATES

1966 ◽  
Vol 44 (4) ◽  
pp. 447-450 ◽  
Author(s):  
Fredrick B. Ogilvie ◽  
Owen G. Holmes
Keyword(s):  
Absorption Spectra ◽  
Ultraviolet Absorption ◽  
Spectral Changes ◽  
Alkali Chlorides

The spectrum of RhCl3 in fused LiCl–KCl at 440 °C is sufficiently different from that of RhCl63− to suggest the existence of some other species such as dimeric or polymeric bridge-complexes, or, less likely, tetrahedral RhCl4−. The spectra of RhCl3 and K3Rh(NO2)6 in fused NaNO3–KNO3 at 300 °C indicate the occurrence of nitro coordination in both systems, probably completely in the latter case, but in competition with chloro coordination in the former. Addition of KCl to a solution of RhCl3 in NaNO3–KNO3 causes spectral changes which suggest that RhCl63− is the principal rhodium species present.

Halogen-Substitution Effect on the Optical Absorption Bands of Uracil*

1974 ◽  
Vol 29 (9-10) ◽  
pp. 493-495 ◽  
Author(s):  
Wolfgang Lohmann
Keyword(s):  
Optical Absorption ◽  
Linear Function ◽  
Absorption Spectra ◽  
Electron Affinity ◽  
Substitution Effect ◽  
Ultraviolet Absorption ◽  
Red Shift ◽  
Electron Affinities ◽  
Absorption Bands ◽  
Extinction Coefficients

Abstract The ultraviolet absorption spectra of uracil and its 5-halogenated derivatives have been in ­ vestigated in regard to the electron attracting properties of the substituents. It could be shown that the position of the two absorption bands is proportional to the inverse of the electronegativity; the extinction coefficients are a linear function of the electron affinities. In this way, the red shift obtained upon substitution with halogens can be explained. Also, the decrease in absorbance of the absorption bands at λ > 250 nm, occuring concomitant­ ly, is understandable. The increase in absorbance with increasing electron affinity, as observed in the case of the absorption bands at λ < 250 nm, might question the assumption that this band is due to a higher pi -pi* excitation

THE ULTRAVIOLET ABSORPTION SPECTRA OF THE FERRIC ION AND ITS FIRST HYDROLYSIS PRODUCT IN AQUEOUS SOLUTIONS

1957 ◽  
Vol 35 (9) ◽  
pp. 1002-1009 ◽  
Author(s):  
R. C. Turner ◽  
Kathleen E. Miles
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Perchloric Acid ◽  
Hydrolysis Product ◽  
Ultraviolet Absorption ◽  
Ferric Ion ◽  
Absorption Bands

The absorption spectra of the ferric ion and its first hydrolysis product in an aqueous solution of perchloric acid was determined. The Fe3+ ion has two absorption bands, one with a maximum at 240 mμ and another which extends into the region below 200 mμ. The FeOH2+ ion also has two absorption bands, the maxima of which occur at 300 mμ and 205 mμ. A figure shows the magnitude of the absorption of each of these ions from 200 to 350 mμ.

THE ULTRAVIOLET ABSORPTION SPECTRA OF ALIPHATIC NITRAMINES, NITROSAMINES, AND NITRATES

1949 ◽  
Vol 27b (11) ◽  
pp. 828-860 ◽  
Author(s):  
R. Norman Jones ◽  
G. Denis Thorn
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Ultraviolet Spectrum ◽  
Ultraviolet Absorption ◽  
Absorption Bands ◽  
Structure Formula ◽  
New Compounds

The ultraviolet absorption bands associated with the following groups have been investigated in a variety of compounds of known structure:[Formula: see text]The groups may be characterized by the ultraviolet spectrum, and the number of each type of group present in a given compound may be estimated from an analysis of the shape and intensity of the absorption spectrum. These correlations have been applied to the elucidation of the structure of new compounds isolated in the course of the investigation of the chemistry of 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX).

LIGHT ABSORPTION STUDIES: PART XVII. THE ULTRAVIOLET ABSORPTION SPECTRA OF CHLOROBENZENES

1960 ◽  
Vol 38 (7) ◽  
pp. 1104-1112 ◽  
Author(s):  
W. F. Forbes
Keyword(s):  
Absorption Spectra ◽  
Chlorine Atom ◽  
Light Absorption ◽  
Fluorine Atom ◽  
Ultraviolet Absorption ◽  
Electronic Interaction ◽  
Mesomeric Effect ◽  
Spectral Changes ◽  
Absorption Studies ◽  
Solute Interactions

The ultraviolet absorption spectra of a series of chlorobenzenes are determined. The spectral data suggest that the apparent mesomeric effect of the chlorine atom is greater than that of the fluorine atom, that solvent–solute interactions are generally less important in chlorobenzenes than in fluorobenzenes, and that, as expected, the effective interference radius of the chlorine atom is large. Moreover, spectral changes in o-substituted chlorobenzenes are consistent with the assumption that maximum electronic interaction requires the chlorine atom to be in the same plane as the benzene ring. The conformations of o-chloroacetophenone and o-chlorophenol are briefly discussed.

The infrared and ultraviolet absorption spectra of diimide (N2H2)

1968 ◽  
Vol 46 (8) ◽  
pp. 1005-1011 ◽  
Author(s):  
A. Trombetti
Keyword(s):  
Infrared Spectrum ◽  
Absorption Spectra ◽  
Ground State ◽  
Vacuum Ultraviolet ◽  
Ultraviolet Spectrum ◽  
Ultraviolet Absorption ◽  
Electronic Ground State ◽  
Trans Conformation ◽  
Ultraviolet Spectra ◽  
Electronic Ground

The infrared spectrum of N2H2 in the 3.1 μ region and the ultraviolet spectra of N2H2 and N2D2 have been examined. The analysis of the infrared spectrum indicates that N2H2 in the ground state has a planar trans-conformation with with rN−N = 1.238 ± 0.007 Å and [Formula: see text], assuming rN−H to be between 1.05 and 1.08 Å. In the vacuum ultraviolet spectrum near 1700 Å, progressions of bands with spacings of 1180 and 950 cm−1 have been observed for N2H2 and N2D2, respectively. From the intensity alternation in the J structure of the vacuum ultraviolet spectrum it seems to follow that the electronic ground state of N2H2 is not totally symmetric.

THE SYNTHESIS AND ULTRAVIOLET SPECTRA OF SOME PYRAZOLONES

1951 ◽  
Vol 29 (2) ◽  
pp. 182-191 ◽  
Author(s):  
Paul E. Gagnon ◽  
Jean L. Boivin ◽  
Paul A. Boivin ◽  
R. Norman Jones
Keyword(s):  
Absorption Spectra ◽  
Ultraviolet Absorption ◽  
Ultraviolet Spectra

Twenty-five pyrazolones were prepared by reacting mono- or disubstituted cyanoacetic esters with hydrazine, phenylhydrazine and semicarbazide. 4-Benzyl-3-amino-1-phenyl-5-pyrazolone has been synthesized and its properties have been compared with those of the corresponding 2-phenylpyrazolone derivative. The ultraviolet absorption spectra of several pyrazolones have been determined.

On the photoelectron and ultraviolet spectra of molecules containing a divalent sulfur atom and a carbonyl group separated by a methylene group

1976 ◽  
Vol 54 (19) ◽  
pp. 3026-3030 ◽  
Author(s):  
P. R. Olivato ◽  
H. Viertler ◽  
B. Wladislaw ◽  
K. C. Cole ◽  
C. Sandorfy
Keyword(s):  
Carbonyl Group ◽  
Absorption Spectra ◽  
Sulfur Atom ◽  
Lone Pair ◽  
Ultraviolet Absorption ◽  
Photoelectron Spectra ◽  
Ultraviolet Spectra ◽  
Methylene Group ◽  
Divalent Sulfur

Photoelectron spectra show that in CH3SCH2COCH3 the sulfur and carbonyl lone pair orbitals [Formula: see text] are both stabilized with respect to the compounds containing S or CO only. This is in keeping with the observed values of the basicity constants. The ultraviolet absorption spectra contain the expected [Formula: see text] and [Formula: see text] bands and give evidence for a significant amount of mixing between the excited orbitals.

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