title: Evidence for a transition between singlet and triplet states in the electrochemical reduction of 2,2'-4,4'-tetranitrobiphenyl.
abstract: Two different dianionic species, close in energy, result from the electroreduction of 2,2'-4,4'-tetranitrobiphenyl, 1. The first-formed species has biradical characteristics, such as a triplet EPR spectrum, but it slowly evolves to another EPR-silent species, essentially described as a quinoid form. DFT calculations also support the existence of two dianionic states of the dianion, singlet and triplet, differing by less than 10 kcal mol(-1) (in the gas phase); the quinoid singlet state is more stable.
authors.affiliation: Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain. Iluminada.Gallardo@uab.es
authors.forename: I
authors.initials: I
authors.lastname: Gallardo
authors.forename: G
authors.initials: G
authors.lastname: Guirado
authors.forename: J
authors.initials: J
authors.lastname: Marquet
authors.forename: M
authors.initials: M
authors.lastname: Moreno