Unstable intermediates. Part XCV. Electron spin resonance spectra assigned to the radicals POCl3–, POCl2, PO2Cl2, PCl2, and PCl4 in γ-irradiated POCl3, PCl3, and PCl5

Abstract

After exposure of phosphoryl chloride to ⁶⁰Co γ-rays at 77 K, three radical species were detected. One, having a large ³¹P hyperfine coupling of about 1350 G is thought to be POCl₃^–, having two strongly coupled chlorine atoms (A_iso 66 G) and one weakly coupled chlorine atom (A_isoca. 20 G). The second species, thought to be POCl₂ gave an axially symmetric spectrum at 77 K, but this became isotropic on warming the sample to 100 K, when A_iso(³¹P) was 759 G and A_iso(³⁵Cl) was 18 G.

The third major species, thought to be PO₂Cl₂, had A_iso(³¹P) 43 G and A_iso(³⁵Cl) 3 G. This species was probably formed from HPO₂Cl₂ impurity.

With similar treatment, phosphorus trichloride gave PCl₂ and PCl₄ radicals whilst the pentachloride gave PCl₄ and an unidentified radical containing two chlorine atoms.