Reversible Single Electron Redox Steps Convert Polycycles with a C ₃ P ₃ Core to a Planar Triphosphinine

Reaction of the imidazolium-stabilized diphosphete-diide IDP with trityl phosphaalkyne affords a mixture which contains molecules 1 and b central C3P3 core, formally carries two-fold negative charge. In order to avoid formation an antiaromatic 8π electron system within conjugated dianionic six-membered [C3P3]2− ring, adopts bicyclic [3.1.0] tricyclic [2.2.0.0] structure are in dynamic equilibrium. a, can be reversibly oxidized triphosphinine dication [5]2+ flat aromatic ring. This two-electron redox reaction occurs two single-electron transfer steps via 7π-radical cation [4]⋅+, could also isolated fully characterized. The profound reversible structural change observed for couple [5]2+/1 is sharp contrast C6H6/[C6H6]2− couple, undergoes only modest deformation.