Valence Isomerization in the Solid State: From 1,3-Diphosphacyclobutane-2,4-diyl to 1,2-Dihydro-1,2-diphosphete

Abstract

The butadiene-like phosphanylcarbene 2 is, according to ab initio calculations, the intermediate in the conversion of 1 into 3 in the solid state [Eq. (a)]; it is only 1.3 kJ mol−1 higher in energy than 1. For this conversion, only minor changes in the endocyclic bonds are required throughout the entire reaction. R2N=2,2,6,6-Me4C5H6N.