The First 2<i>H</i>‐Phosphirene

Abstract

In phosphirenes the bonding situation is the opposite of that found in azirines: Whereas the 1Hderivatives are stable in the former, it is the 2Hderivatives which are stable in the latter. The first 2H-phosphirene 3 has sbeen obtained along with 2 by photolysis of the 3H-1,2,4-diazaphospate in pentane at −40°C. An X-ray structure analysis of the “end-on” complex 4 revealed that the P-C bond is remarkably short (1.634(4)%Å).