Infrared and Raman correlations of arylaldehyde azines : Asymmetric and symmetric (CN)2 stretching

Nyquist, Richard A.; Peters, T. L.; Budde, Paul B.

doi:10.1016/0584-8539(78)80046-4

Cited by 22 publications

(7 citation statements)

References 3 publications

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“…The study also showed that the two Raman active stretches, ν(NN) and ν sym (CN), were sensitive to the particular benzene substitutions, so that the ν(NN) and ν sym (CN) stretches varied from 1000 to 1067 cm −1 and from 1535 to 1564 cm −1 , respectively. These results confirm the report by Nyquist et al54 that the ν sym (CN) vibrations in the Raman spectra of nineteen benzaldyde azine compounds ranged from 1539 to 1563 cm −1 . Furthermore, the 1098 cm −1 Raman band in acetone azine was assigned by Harris et al55 to a ν(NN) stretch vibration with substantial π‐character.…”

Section: Resultssupporting

confidence: 92%

Azine bridge formation during the electrografting of acrylonitrile

Easter

Taylor

2009

J. Polym. Sci. A Polym. Chem.

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We report the electrografting of polyacrylonitrile (PAN) films onto evaporated gold, silver, and copper substrates, and onto platinum foil. The FTIR spectra of the films are virtually identical to library spectra of PAN and show no evidence of the cyclization observed by some authors. Raman spectra of the same films, however, display a broad absorption band centered at $1520 cm À1 and a second band at 1096 cm À1 , which are neither present in spin-coated films of commercially obtained PAN nor are they present in the FTIR spectra. These previously unreported Raman bands are dependent on a number of factors in the electrografting process; the working electrode metal, the monomer concentration, the solvent used, and the electrochemical protocol used for cleaning the working electrode. The relative intensity of the bands was found to be strongest in films grown on platinum and weakest in those grown on gold, and stronger in thin films (\50 nm) than in thick films ([100 nm). We suggest that these new spectral features are associated with azine-linked polymer chains in a ladder-like structure close to the electrode surface as a result of the predominantly isotactic brush-like conformation of the polymer during the early stages of electrografting.

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Section: Resultssupporting

confidence: 92%

Azine bridge formation during the electrografting of acrylonitrile

Easter

Taylor

2009

J. Polym. Sci. A Polym. Chem.

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“…Spectra shows a band at 3447 and 2888 cm -1 [55] assigned to intermolecular hydrogen bonded υ(OH) for I and II respectively. The bands appearing around 1600 cm -1 are assigned to the ν(C=N) [56,57]. However, the absorption bands appearing at 1183 and 1175 cm -1 are assigned to the υ (N-N) [58,59] stretching for three compounds.…”

Section: Ir Spectra Analysesmentioning

confidence: 97%

Synthesis, molecular structure analyses and DFT studies on new asymmetrical azines based Schiff bases

Yahyaoui

Bouchama²,

Anak³

et al. 2019

Journal of Molecular Structure

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In this paper, we report the synthesis of new unsymmetrical azines Schiff bases. These compounds were prepared by condensation of hydrazine with different aldehydes and ketones to give (E) -2-hydroxynaphthalene-1-carbaldehyde [(1E) -2-thienylmethylene] hydrazone compound (I) and (Z) -2 -[(E) -1-(2-hydroxyphenyl) ethylidenehydrazin-1-ylidene] -1,2diphenylethanone compound (II). The method adopted consists in reacting the two different carbonyl compounds simultaneously in one step in a stepwise manner reported which is practical and cost-effective. The reaction with a minor modification in operating conditions proceeded efficiently and with excellent performance. The structure of each of the two compounds (I) and (II) was determined by the X-ray diffraction technique performed on single crystals. The asymmetric unity of the two molecules consists of one asymmetry-independent molecule. In addition, hydrogen bonds C-H ... π are observed in the compound (II). We then present a detailed DFT study based on B3LYP / 6-31G (d, p) geometric structures of compounds (I); (II) and another compound (III) also another asymmetric azine (Z) -2 -[(E) -2-benzylidenehydrazine-1-ylidene] -1,2diphenylethanone whose crystal structure is reported. The fundamental vibration wave numbers are calculated and a good agreement between the observed and calculated wave numbers is obtained. The study was extended to the HOMO-LUMO analysis to calculate the energy gap. The calculated HOMO and LUMO energy reveals that the charge is transferred into the molecule.

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“…In general, aldazines and ketazines are characterized by a strong infrared band in the 1665-1635 cm -I range. Araldehyde azines have been studied by Nyquist et al [117]. In some 20 compounds they find the antisymmetric C=N band in the range 1637-1636cm-l , where it occurs with medium to strong intensity.…”

Section: (Di) Azinesmentioning

confidence: 98%

Alkenes and Vibrations of C=N and N=N Links

Bellamy¹

1980

The Infrared Spectra of Complex Molecules

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A good deal of new data has accumulated on the positions of C=C absorptions in different chemical environments, so that we are now in a better position to discuss the various factors which control the frequency shifts. But it is clear that, in this instance, both chemical and physical factors are important, and much remains to be done to determine the relative impacts of each. These two factors can be simply defined as follows. Chemical effects arise from alterations in the electron distribution within the bond which follow the replacement of one substituent by another. There is therefore a change in bond character which is reflected in an altered force constant and a shift in the vibrational frequency. However, the vibrational frequency can also be affected by factors such as substituent mass, bond-angle changes and vibrational coupling. These are purely physical effects, and they do not correspond to any change in the force constant of the bond, except insofar as angle changes may affect the hybridization. In many situations both types of effect are in operation. In conjugated systems, for example, the force constant of the bond is lowered as compared with the non-conjugated case, due to the delocalization of the 7t electrons. This leads to a shift to lower frequencit:s. However, there is now an increased possibility of vibrational coupling between the two C=C links, which will modify the frequency, although in itself it does not alter the force constants.Some of the most informative studies in this field have been those concerned with the effects of bond-angle changes and of ring strain, and these will therefore be considered first, as they illustrate very well the substantial impact of physical effects, and the difficulties which arise in disentangling them from the chemical effects which occur simultaneously.

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Infrared and Raman correlations of arylaldehyde azines : Asymmetric and symmetric (CN)2 stretching

Cited by 22 publications

References 3 publications

Azine bridge formation during the electrografting of acrylonitrile

Azine bridge formation during the electrografting of acrylonitrile

Synthesis, molecular structure analyses and DFT studies on new asymmetrical azines based Schiff bases

Alkenes and Vibrations of C=N and N=N Links

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