Roaming-mediated isomerization in the photodissociation of nitrobenzene

Michael L. Hause, Nuradhika Herath, Rongshun Zhu, Ming-Chang Lin, Arthur G. Suits*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

107 Scopus citations


Roaming reactions comprise a new class of reaction in which a molecule undergoes frustrated dissociation to radicals, followed by an intramolecular abstraction reaction. Nitro compounds have long been known to dissociate to give NO as a major product. However, rates based upon isomerization via calculated tight transition states are implausibly slow, so the key dissociation pathway for this important class of molecules remains obscure. Here, we present an imaging study of the photodissociation of nitrobenzene with state-specific detection of the resulting NO products. We observe a bimodal translational energy distribution in which the slow products are formed with low NO rotational excitation, and the fast component is associated with high rotational excitation. High-level ab initio calculations identified a 'roaming-type' saddle point on the ground state. Branching ratio calculations then show that thermal dissociation of nitrobenzene is dominated by 'roaming-mediated isomerization' to phenyl nitrite, which subsequently decomposes to give C 6H 5O + NO.

Original languageEnglish
Pages (from-to)932-937
Number of pages6
JournalNature Chemistry
Issue number12
StatePublished - 1 Dec 2011


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