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).

scholarly journals The absorption spectra of halogens and inter-halogen compounds in solution in carbon tetrachloride

1929 ◽  
Vol 124 (795) ◽  
pp. 604-616 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Carbon Tetrachloride ◽  
Absorption Spectra ◽  
Spectroscopic Data ◽  
Chemical Interaction ◽  
Chemical Compounds ◽  
Absorption Bands ◽  
Halogen Compounds ◽  
Inert Solvent ◽  
The Mean

When two solutions are mixed the absorption spectrum of the new solution will be the mean of those of the separate solutions provided that no chemical interaction occures. The mere fact of a departure from additivity does not, however, necessarily denote the formation of true chemical compounds. The solute or solutes may undergo solvation, loosely bound aggregates may occur, and even when marked deviations from the simple law of mixtures are observed it is rarely possible to prove the quantitative formation of a given chemical compound from spectroscopic data alone. The above considerations apply with some force to the problem of the absorption spectra of halogens and inter-halogen compounds in an inert solvent. The three elements show perfectly characteristic absorption bands, they are known to interact with the formation of some quite stable compounds, some relatively stable compounds, and some apparently very unstable compounds.

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 A2Πi–X2Πi absorption spectrum of BrO

1981 ◽  
Vol 59 (12) ◽  
pp. 1908-1916 ◽  
Author(s):  
M. Barnett ◽  
E. A. Cohen ◽  
D. A. Ramsay
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Ground State ◽  
Flash Photolysis ◽  
Absorption Bands ◽  
Long Wavelength ◽  
Numbering Scheme ◽  
Ozonized Oxygen ◽  
Good Agreement

Absorption spectra of isotopically enriched 81Br16O and of normal BrO have been obtained by the flash photolysis of mixtures of bromine and ozonized oxygen. Rotational analyses are given for the 7–0, 12–0, 18–0, 19–0, 20–0, 21–0, 7–1, and 20–1 A2Π3/2–X2Π3/2 sub-bands of 81Br16O. The value for [Formula: see text] is found to be 722.1 ± 1.1 cm−1 in good agreement with the value calculated from microwave constants. Several additional bands have been found at the long wavelength end of the spectrum, necessitating a revision of the vibrational numbering scheme for both the emission and absorption bands. "Hot" bands up to ν″ = 6 have been observed in the absorption spectrum for the 2Π3/2 component of the ground state but no bands have yet been identified from the 2Π1/2 component.

scholarly journals The absorption spectra of conjugated dienes in the vacuum ultra-violet (1)

1940 ◽  
Vol 174 (957) ◽  
pp. 220-234 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Electronic Structures ◽  
Spectroscopic Data ◽  
Ultra Violet ◽  
Conjugated Dienes ◽  
Strong Absorption ◽  
Absorption Bands ◽  
Lennard Jones ◽  
Vacuum Ultra Violet

Butadiene is important as the simplest example of resonance between two conjugated double bonds. The comparison of its ultra-violet absorption spectrum with that of ethylene might be expected to give some indication of the way the π electrons of the molecule are affected by the resonance. The electronic structures of a number of molecules for which resonance is important have been worked out theoretically by Hückel (1935), Lennard- Jones (1937), Sklar (1937) and Mulliken (1939 a and b ). The purpose of the present work is to obtain spectroscopic data with which the theoretical expectations can be compared. As most of the strong absorption bands of these molecules occur at wave-lengths less than 2000 A, the investigation falls naturally into the region of vacuum spectroscopy.

Spectroelectrochemical Study of some μ3-Oxo-μ-acetato Trinuclear Rhodium(III) and Iridium(III) Complexes

1995 ◽  
Vol 50 (4) ◽  
pp. 551-557 ◽  
Author(s):  
Kenta Takahashi ◽  
Keisuke Umakoshi ◽  
Akihiro Kikuchi ◽  
Yoichi Sasaki ◽  
Masato Tominaga ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Electronic Absorption Spectrum ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Visible Region ◽  
Absorption Bands ◽  
Visible Absorption ◽  
The One ◽  
Species Being

New trinuclear rhodium(III) complexes, [Rh3(μ3-O)(μ-CH3COO)6(L)3]+ (L = imidazole (Him), 1-methylimidazole (Meim), and 4-methylpyridine (Mepy)) have been prepared. The Him, Meim, and Mepy complexes show reversible one-electron oxidation waves at E1/2 = +1.12, +1.12, and +1.28 V vs Ag/AgCl, respectively, in acetonitrile. Electronic absorption spectra of the one electron oxidized species of these complexes and [Rh3(μ3-O)(μ-CH3COO)6(py)3]+ (py = pyridine) (E1/2 = +1.32 V ) were obtained by spectroelectrochemical techniques. While the Rh3(III,III,III) states show no strong visible absorption, the Rh3(III,III,IV ) species give a band at ca. 700 nm (ε = 3390-5540 mol dm-3 cm-1). [Ir3(μ3-O)(μ-CH3COO)6(py)3]+ with no strong absorption in the visible region, shows two reversible one-electron oxidation waves at +0.68 and +1.86 V in acetonitrile. The electronic absorption spectrum of the one-electron oxidized species (Ir3(III,III,IV )) also shows some absorption bands (688 nm (ε, 5119), 1093 (2325) and 1400 (ca. 1800)). It is suggested that the oxidation removes an electron from the fully occupied anti-bonding orbital based on metal-dπ-μ3-O-pπ interactions, the absorption bands of the (III,III,IV ) species being assigned to transitions to the anti-bonding orbital.

Colouring Matters of Australian Plants. II. Naphthoquinones from Diospyros hebecarpa A. Cunn

1952 ◽  
Vol 5 (4) ◽  
pp. 760 ◽  
Author(s):  
RG Cooke ◽  
H Dowd
Keyword(s):  
Absorption Spectra ◽  
Ultraviolet Absorption ◽  
Ether Extraction ◽  
New Compounds ◽  
Related Compounds

Ether extraction of Diospyros hebecarpa A. Cunn. yields plumbagin, and two new compounds which are shown to be 5-hydroxy-7-methyl-1,4-naphthoquinone and 1,4-diketo-5-hydroxy-7-methyl-1,2,3,4-tetrahydronaphthalene. The ultraviolet absorption spectra of these and related compounds are recorded, and the synthesis of 1,4,5-tri-methoxy-7-methylnaphthalene is described.

scholarly journals The Near-ultraviolet Absorption Spectrum of Diimide Vapor

1974 ◽  
Vol 52 (6) ◽  
pp. 1006-1012 ◽  
Author(s):  
R. A. Back ◽  
C. Willis ◽  
D. A. Ramsay
Keyword(s):  
Absorption Spectrum ◽  
Bond Length ◽  
Gas Phase ◽  
Absorption Spectra ◽  
Ground State ◽  
Ultraviolet Absorption ◽  
Ultraviolet Absorption Spectrum ◽  
Near Ultraviolet ◽  
Bending Mode ◽  
Franck Condon

Absorption spectra of N2H2 and N2D2 in the gas phase have been obtained in the region 3000–4300 Å, consisting of about 30 diffuse bands for each compound. Long progressions in the spectra are attributed to excitation of the H—N=N bending mode, v2′, in the upper state, with much shorter progressions arising from the N=N stretching mode, v3′; values of v2′ = 1215 and 910 cm−1 and v3′ = 1550 and 1440 cm−1 were estimated for N2H2 and N2D2 respectively.The spectra are attributed to the 1Bg ← 1Ag(π* ← n+) transition of trans diimide, probably made allowed by vibronic interaction. From Franck–Condon calculations the H—N=N angle in the upper state was estimated to be 132 ± 2°, an increase of 25° from the ground-state value; the increase in the N=N bond length was estimated to be about 0.05 Å.

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 NITROGUANIDINE DERIVATIVES

1953 ◽  
Vol 31 (1) ◽  
pp. 42-47 ◽  
Author(s):  
A. F. McKay ◽  
C. Sandorfy
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Linear Structure ◽  
Addition Product ◽  
Ultraviolet Absorption ◽  
Ethanol Addition ◽  
Nitroguanidine Derivatives ◽  
Amine Addition

The ultraviolet absorption spectra of the ammonia and amine addition products of 1-nitro-2-nitramino-2-imidazoline verify the linear structure A for these compounds. Also the ethanol addition product is considered on the basis of [Formula: see text]its absorption spectrum to be N-β-nitraminoethyl-N-nitro-o-ethylisourea. The relative effects of the nitramino and nitroguanidine chromophores on the absorption spectra of several nitroguanidine derivatives are discussed.

scholarly journals IV. On the absorption-spectra of bromine and iodine monochloride

1877 ◽  
Vol 25 (171-178) ◽  
pp. 4-4
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Graphical Method ◽  
Wave Length ◽  
Iodine Monochloride ◽  
Absorption Bands ◽  
General Applicability ◽  
Molecular Weights

The paper contains the results of an exact series of measurements of the absorption-spectra of the vapours of the element bromine and of the compound iodine monochloride, made with the object of ascertaining whether the molecules of these two gases vibrate identically or similarly, their molecular weights and colour of the vapours being almost identical. The two spectra, which are both channelled, were compared simultaneously by means of one of Kirchhoff’s 4-prism spectroscopes, the position of the lines being read off by reflection on an arbitrary scale. In order to determine the wave-lengths of these bands, the wave-length of each of 27 air-lines lying between the extremes of the absorption-spectra was ascertained by reference to Thalén’s numbers; whilst for the purpose of reducing the readings of the absorption-bands to wave-lengths a graphical method was employed, the details of which are given in the paper. This method appears to be one of general applicability for the plotting of spectra. Tables then follow giving the wave-lengths of 66 bands of each absorption-spectrum; and a map accompanies the text in which the bands are drawn to a scale one half that of Ångström’s “Spectre Normal.”

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