Anionic 1,4-dihydro-1,4-diphosphinines were synthesized from tricyclic 1,4-diphosphinines and isolated as blue powdery salts M[ 2a – 2c ]. Reaction of solutions of these monoanions with iodomethane led to P -methylated compounds 3a – 3c . An oxidation/reduction cycle was examined, starting from solutions of K[ 2a ] via P–P coupled product 4a and back to K[ 2a ], and the recyclability and redox chemistry of this cycle were confirmed by experimental and simulated cyclic voltammetry analysis, which is proposed as a potential 2-electron cathode for rechargeable cells. TD-DFT studies were used to examine species that might be involved in the process.

Formation of anionic ditopic N-heterocyclic dicarbene having two linking phosphorus centers – one neutral and one anionic is presented, along with a first glimpse on the coordination chemistry of bis(imidazolium) salts.

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