%0 Journal Article
%A Stevens, John
%A Schweizer, Marcus
%A Rauhut, Guntram
%D 2001
%T Toward an Understanding of the Furoxan−Dinitrosoethylene
Equilibrium
%U https://acs.figshare.com/articles/journal_contribution/Toward_an_Understanding_of_the_Furoxan_Dinitrosoethylene_Equilibrium/3634473
%R 10.1021/ja010792c.s001
%2 https://acs.figshare.com/ndownloader/files/5723223
%K ci
%K dinitrosoethylene
%K transition state
%K singlet pathway
%K transition states
%K alternative routes
%K nitroso groups
%K T 1 surfaces
%K perturbational methods
%K S 0
%K benzofuroxan
%K Model potentials
%K density functionals
%X The tautomerism of furoxan (1,2,5-oxadiazole-2-oxide) has been investigated by different
computational methods comprising modern density functionals as well as single-reference and multi-reference
ab initio methods. The ring-opening process to 1,2-dinitrosoethylene is the most critical step of the reaction
and cannot be treated reliably by low-level computations. The existence of cis−cis−trans-1,2-dinitrosoethylene
as a stable intermediate is advocated by perturbational methods, but high-level coupled-cluster calculations
identify this as an artifact. In contrast to the analogous reaction in benzofuroxans, cis−cis−cis-1,2-dinitrosoethylene was found to be a transition state rather than a local minimum. Model potentials were used
to explain the occurrence and the disappearing of transition states and local minima relative to the reaction of
benzofuroxan. Low-lying triplet states that can be accessed due to spin−orbit coupling were investigated as
taking part in alternative routes to a proposed singlet pathway. Barriers for rotations of the nitroso groups on
the S0 and T1 surfaces are reported.
%I ACS Publications