Triphosphenium salts: air-stable precursors for phosphorus(I) chemistry

The chemistry of low-coordinate phosphorus-containing species is an area of intense interest in modern main group chemistry. While typical routes for accessing such species include pyrophoric phosphorus-centered precursors or harsh reducing agents, triphosphenium cations represent a more convenient and safer alternative. This Perspective summarizes the use of air- and moisture-stable triphosphenium salts of [dppeP]+ as a source of P+ ions for the generation of a variety of new and/or useful low-coordinate phosphorus-containing species. These range from phosphorus-rich oligomers to phosphamethine cyanine dyes. Special emphasis is placed on the electronic structure of the newly generated species as well as their subsequent reactivity.