Azides of heavier main group elements: The reluctance of phosphine azides to undergo a curtius-type rearrangement

Crystal structure of 2-azido-1,3-bis(2,6-diisopropylphenyl)-1,3,2-diazaphospholidine

“…One of the most interesting properties of these molecules is that both free and coordinated alkyl and aryl derivatives are much more reactive than their corresponding amino derivatives, as demonstrated by their lower thermal and photochemical stability. For example, the phosphinoazide complex Ph 2 P(N 3 )-Cr(CO) 5 readily undergoes photolysis under UV light to produce the phosphino-isocyanate complex Ph 2 P(NCO)-Cr(CO) 5 (Ocando et al, 1985), while the related bis(diisopropylamino) complex (iPr 2 N) 2 P(N 3 )-Cr(CO) 5 does not (Cowley et al, 1995). The crystal structure of the title compound is the first reported example of a structurally characterized 2-azido-1,3,2-diazaphospholidine; however, a few closely related compounds are known, such as those derived from 1,3,2-diazaphospholenes.…”