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Studies on Radical Cations, III. The Type C Valence‐Isomeric System Quadricyclane Radical Cation/Norbornadiene Radical Cation
Author(s) -
Haselbach Edwin,
Bally Thomas,
Lanyiova Zuzana,
Baertschi Peter
Publication year - 1979
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19790620226
Subject(s) - norbornadiene , quadricyclane , chemistry , mindo , radical ion , valence (chemistry) , ion , computational chemistry , photochemistry , molecule , organic chemistry , catalysis
The previously discussed principles involved in electrocyclic reactions of openshell ions are exemplified for a type C system, the radical cation couple quadricyclane + ( Q + )/norbornadiene + ( NBD + ). Exhaustive calculations (MINDO/3) for the various states of the ions support the general predictions for such types of systems. The barrier of interconversion Q + → NBD + is estimated to be significantly lower than that for the corresponding neutrals. Experimental support to this prediction is obtained by γ‐irradiation of Q or NBD in an electron scavenging matrix. In both cases only NBD + is observed, indicating that Q + is not stable at 77 K. Previous observations and propositions referring to the system Q + / NBD + are discussed in view of the present findings.