CONFORMATION ISOMERIZATION OF HEXAHYDRO-L,3,5-TRIMETHYL-1,3,5-TRIAZINE.
ILLINOIS UNIV URBANA DEPT OF CHEMISTRY AND CHEMICAL ENGINEERING
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The H high-resolution spectrum of hexahydro-1,3,5-trimethyl-1,3,5-triazine was observed at temperatures from -58 to 42C. The rate of conformational isomerization was determined by a complete line-shape analysis method over the temperature range-26 to 42C. From these rates, the activation parameters were determined to be 15.2 plus or minus 0.2 and 13.2 plus or minus 0.2 kcalmole and 7.5 eu, respectively, at the coalescence temperature of 268.1K. It is proposed that the mechanism of conformational isomerization involves inversion of the ring in synchronism with inversion of one or two of the nitrogen atoms, followed or proceeded by a fast inversion of the other nitrogens. s-Trioxane and 2,4,6-hexamethyl-1,3,5-trithiane HMTT were studied also. The isomerization rate of s-trioxane proved to be too fast for measurement and that of HMTT too fast for a complete study. However, spin-echo measurements of the latter gave an approximate value of 8 kcalmole for the free energy of activation. Author
- Organic Chemistry
- Atomic and Molecular Physics and Spectroscopy