Author:

Keywords:

Science & Technology, Physical Sciences, Polymer Science

Abstract:

It is well known that NH proton exchange in azole heterocycles (pyrazoles, imidazole, vic- and sym-triazoles, and tetrazoles) occurs so rapidly at room temperature that an averaged tautometer is usually observed in the **1H, **1**3C, and **1**4N spectra. To observe the tautomeric species by NMR spectroscopy, it is necessary to slow down the rate or prototropic rearrangement by cooling the solution below minus 100 degree C. In the reported experiments, NMR spectra were obtained on a Varian XL 100-15 spectrometer equipped for CW (**1H) and FT (**1**3C) operations. Both **1H and **1**3C chemical shifts are referred to internal TMS. For **1**3C spectra run in DMSOd//6, the central peak of the solvent was used as internal reference and was assumed to absorb at 39. 6 ppm vs. TMS. 4-Vinyltriazole was prepared from 4-formyltriazole by a Wittig reaction. Polymerization of 4-vinyltriazole was carried out in dimethylformamide at 65 degree c and initiated by azobisisobutyronitrile. Experimental data obtained from NMR spectra are tabulated, plotted and discussed in terms of mechanisms of the NH proton exchange.