Diphosphene, bis

Phosphaalkenes display a number of unusual properties. An investigation of phosphaalkenes with several aryl substituents, revealed that bis(diphosphene) 19 forms a triplet dianion211. A cumulene structure was demonstrated for the Ar-P = C=C=P-Ar radical anion. The unpaired electron is predominately localized on the P atoms212. 

Treatment of the diphosphenium salt (223) with lithium diisopropylamide results in a high yield conversion into the diphosphirane (224), alkylation of which gives a diphosphiranium salt. EPR techniques have been used to study the products of sodium reduction of the bis(diphosphene) (225) and related phosphaalkenes. ... 

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