Ring vibrations heteroaromatic

Because of the participation of the enamine double bond in the resonance of the aromatic ring of heteroaromatic /J-enamino esters, the group frequency character of the individual bands is low. Thus the El band is essentially vc=Q. Similarly, jS-enamino nitriles do not exhibit coupled vibrations since the nitrile absorption does not participate.24,61... 

The most characteristic feature of the infrared spectra of all 5-mono- and -di-substituted-amino-l,2,3,4-thiatriazoles is a strong band in the 1540-1590 cm range, which without doubt is due to the C=N and N=N stretching vibrations of the heteroaromatic ring system. Various infrared bands between 889 and 1122 cm have been assigned to skeletal vibrations of the thiatriazole ring and a band... 

The crystal and molecular structures of (-)-28 hydrochloride have been determined by X-ray crystallography ( )-28 possesses the R configuration at C-3, and the pyrrolidine ring is in the envelope conformation (67). C-NMR spectra of 28, vasicinone (29), and related compounds have been reported (68), and the mass spectral fragmentations of 28, vasicinone (29), deoxyvasicine (32), and deoxyvasicinone (33) (Fig. 2) have been discussed (69,70). The mass spectral behavior of 2,3-polymethylene-3,4-dihydroquinazolin-4-ones (71) and of 2,3-polymethylene-1,2,3,4-tetrahydroquinazolin-4-ones (72) have been studied. Integrated intensities of the 1480-1630-cm IR bands of the skeletal vibrations of the heteroaromatic rings of pyrroloquinazoline alkaloids have been correlated with electron densities and substituent effects (73). 

The purpose of this paper is therefore to present Resonance Raman Scattoing (RRS) data obtained on a variety of conducting polymers containing either aromatic or heteroaromatic rings and especially to precise what can be gained from an analysis of the vibrational spectra in terms of electronic stractures. 

VIBRATIONAL PROPERTIES OF CONDUCTING POLYMERS WITH AROMATIC OR HETEROAROMATIC RINGS... 

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