THE STRUCTURES OF NITROGUANIDINE AND ITS DERIVATIVES

1951 ◽  
Vol 29 (9) ◽  
pp. 746-758 ◽  
Author(s):  
A. F. McKay ◽  
J. P. Picard ◽  
P. E. Brunet
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Ultraviolet Absorption ◽  
Derivatives Of ◽  
Resonance Hybrid

The ultraviolet absorption spectra of a number of derivatives of nitroguanidine were determined. An analysis of the effects of substituents on the absorption spectrum of nitroguanidine has led to the conclusion that it exists as a resonance hybrid of several structures including (a) and (b).[Formula: see text]The bearing of these structures on the nomenclature of nitroguanidine and its derivatives is discussed. Also the structures of some of the derivatives of nitroguanidine have been interpreted from their absorption spectra.

Polarographic half-wave potentials and ultraviolet absorption spectra of some conjugated heteroenoid compounds

1969 ◽  
Vol 47 (21) ◽  
pp. 4076-4083 ◽  
Author(s):  
H. L. Holmes ◽  
D. J. Currie
Keyword(s):  
Absorption Spectra ◽  
Functional Groups ◽  
Ultraviolet Absorption ◽  
Half Wave ◽  
Active Methylene Compounds ◽  
Derivatives Of ◽  
Active Methylene ◽  
Hammett Relationship

The half-wave potentials of phenyl substituted derivatives for each series of conjugated heteroenoid compounds studied follow a Hammett relationship. The effect of change in the functional groups and of increase in length of the conjugated system upon half-wave potentials and ultraviolet absorption maxima is briefly discussed. Terephthalylidene derivatives of active methylene compounds function like the cinnamylidene derivatives.

THE ULTRAVIOLET ABSORPTION SPECTRA OF SOME CARBOXY DERIVATIVES OF NAPHTHALENE

1949 ◽  
Vol 27b (5) ◽  
pp. 437-461 ◽  
Author(s):  
Y. Hirshberg ◽  
R. Norman Jones
Keyword(s):  
Dicarboxylic Acid ◽  
Absorption Spectra ◽  
General Problem ◽  
Acid Anhydride ◽  
Ultraviolet Absorption ◽  
Dioxane Solution ◽  
Ethanolic Solution ◽  
Complex Molecules ◽  
Steric Inhibition Of Resonance ◽  
Derivatives Of

The ultraviolet absorption spectra of a variety of naphthalene compounds containing phenyl and carboxy substituents are described. The majority of the compounds contain either the naphthalene-1,2-dicarboxylic acid anhydride or the naphthalene-2,3-dicarboxylic acid anhydride ring systems. It is shown that in ethanolic solution the spectra of these anhydrides change over a period of a few hours. The spectra of the anhydrides in n-heptane or dioxane solution do not change on standing. The effects of the various substituents are discussed in terms of steric inhibition of resonance and of antagonistic and reinforcing actions of the substituents, dependent on the position of substitution. The significance of these data are considered in relation to the general problem of the interpretation of the ultraviolet absorption spectra of complex molecules.

Functional group and substituent effects, both steric and electronic, upon the ultraviolet absorption spectra of some N-alkyl- and N,N-dialkyl-derivatives of some cinnamamides and benzalcyanoacetamides

1969 ◽  
Vol 47 (17) ◽  
pp. 3278-3280 ◽  
Author(s):  
A. D. Delaney ◽  
D. J. Currie ◽  
H. L. Holmes
Keyword(s):  
Hydrogen Atom ◽  
Absorption Spectra ◽  
Functional Group ◽  
Substituent Effects ◽  
Ultraviolet Absorption ◽  
Long Wavelength ◽  
Wavelength Absorption ◽  
Derivatives Of

Conjugative and steric constants for N-substituted carboxyamide groups have been derived which allow the calculation of the long wavelength absorption maxima of N-alkyl- and N,N-dialkyl-derivatives of cinnamamide and benzalcyanoacetamide. Deviations between calculated and observed values indicate that there may be steric interference between bulky N,N-dialkylcarboxyamide groups and the benzylic hydrogen atom.

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.

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