The reaction of PR 3 (R = Cy, iPr) with 1-adamantyl azide (N 3Ad) in benzene results in an equilibrium of the starting material and the phosphazide R 3PN 3Ad. Thermodynamic and kinetic measurements were taken of the reaction of P iPr 3 with N 3Ad and yielded ΔH = -18.7 ± 1.0 kcal mol- 1, ΔS = -52.5 ± 2.0 cal mol -1 K -1, ΔH = +12.0 ± 1.0 kcal mol -1, and ΔS = -25.3 ± 1.2 cal mol -1 K -1. The phosphazides, R 3PN 3Ad, do not readily lose N 2 for R = Cy and iPr; however, the reaction of PMe 3 with N 3Ad results in a smooth formation of the phosphazene Me 3P=NAd with N 2 loss. Calorimetric investigations of this reaction led to an estimation of ΔH = -40 ± 3 kcal mol -1 for the loss of N 2 from the intermediate phosphazide R 3PN 3Ad and also yield an estimation of 72 ± 5 kcal mol -1 for the bond dissociation energy of the P=N bond in R 3P=NAd. The X-ray crystal structure of Cy 3PN 3Ad is reported.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry