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.

Tricyclic 1,4-dihydro-1,4-phosphasilines 3a,b were synthesized from Si(NR2)2-bridged compounds 2a,b. Based on calculated FMOs of 3b, forecasting a possible P-selective P-N bond cleavage reduction, a redox cycle could be established using...

This review describes synthetic concepts and breakthroughs in 1,4-diphosphinine and related P-bridged bis(NHCs) chemistry, covering the last four decades, starting from monocyclic 1,4-dihydro-1,4-diphosphinines in the early 80ties to the most...