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

Abstract

Ring-opening isomerization from ring-shaped isomers to chain-shaped isomers of N(8)H(8) 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 N-N single bond by analyzing the length change of N-N 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 N(8)H(8) while four-membered ring-shaped isomers easy in ring-opening are the most unstable.

Theoretical Study on the Isomerization Reaction Mechanism of the Chain-Isomers of N₉H₉

“…On the basis of previous research [20], the chain-shaped isomers have been analyzed, and the sixteen species are found. The structures, stabilities, thermochemical properties and tautomerism between them are studied and discussed.…”

“…In recent years, more and more research on hydronitrogen has been reported about its configuration parameters, vibration frequencies, decomposition reactions and heat of formation [12][13][14][15][16][17][18][19]. We have done a series of theoretical studies on hydronitrogen, such as the structures and stabilities of chain-shaped isomers and ring-shaped isomers of N 8 H 8 [20]. On this basis, the study on the isomerization process of chain-shaped N 9 H 9 isomers is the key point in this article [21][22][23].…”