180626-91-9Relevant articles and documents
Oxidation of phosphines containing two or three tetrathiafulvalene (TTF) or o-dimethyl-TTF moieties. Evidence for formation of radical polycations
Gerson, Fabian,Lamprecht, Axel,Fourmigue, Marc
, p. 1409 - 1414 (1996)
Stepwise oxidation of tetrathiafulvalenyl(diphenyl)phosphine (1), 4′,5′-dimethyltetrathiafulvalen-4-yl(diphenyl)phosphine (1a), bis(tetrathiafulvalenyl)phenylphosphine (2), bis(4′,5′-dimethyl- tetrathiafulvalen-4-yl)phenylphosphine (2a), tris(tetrathiafulvalenyl)phosphine (3) and tris(4′,5′-dimethyltetrathiafulvalen-4-yl)phosphine (3a) was followed by EPR and ENDOR spectroscopy, and cyclic voltammetry. Each of the tetrathiafulvalene (TTF) or 4,5-dimethyltetrathiafulvalene (o-DMTTF) moieties in 1-3a donates two electrons, so that exhaustive oxidation at potentials below 1 V (vs. SCE) leads to the dications 12+ or 1a2+, the tetracations 24+ or 2a4+ and the hexacations 3 6+ or 3a6+. In 2, 2a, 3 and 3a, the electrons are removed one-by-one from different TTF or o-DMTTF moleties. In the initially formed radical cations 2.+, 2.+, 3.+ and 3a .+, the electron hole is delocalized over all TTF or o-DMTTF moieties, two in 2.+ or 2a.+ and three in 3.+ or 3a.+ .On the other hand, in paramagnetic species produced by further oxidation and also giving rise to well defined EPR and ENDOR spectra, the unpaired electron appears on the hyperfine time-scale as localized in only one donor moiety. These species are supposed to be the radical trications 2 .3+ or 2a.3+ and the radical pentacations 3.5+ or 3a.5+. The intermediately occurring dications 22+ or 2a2+ and 32+ or 3a2+, as well as the tetracations 34+ or 3a4+, should have a triplet ground-state, while the trications 33+ or 3a3+ are expected to be quartet species.
