Theoretical study on the ring‐opening isomerization reaction mechanism of the ring isomers of N8H8

Ring-opening isomerization from ring-shaped isomers to chain-shaped isomers of N8H8 has been studied by a density function B3LYP method at 6-311++G** level. 20 ring-shaped isomers have been found to be able to transform into chain-shaped isomers, with 20 possible transition states got by ring-opening structure optimization. Furthermore, the ring-openings have been found in the longer NN single bond by analyzing the length change of NN bond of ring-shaped isomers in ring-opening processes. In addition, with the activation energies in ring-opening processes, the differences of the activation energies in isomerization between the isomers have been found according to the classification of rings. The activation energies in ring-opening isomerization of six-membered ring-shaped isomers are higher than that of the four-membered ring-shaped isomers. It indicates that six-membered ring-shaped isomers difficult in ring-opening in the isomerization are the steadiest ring-shaped isomers of N8H8 while four-membered ring-shaped isomers easy in ring-opening are the most unstable. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011