Unstable intermediates. Part XCIX. Solvated electrons in solid metal–ammonia solutions

Abstract

Rapid freezing of metal–ammonia solutions, containing added salt to inhibit solvent crystallisation, gave blue solids whose e.s.r. spectra were generally characterised by three distinct features: (i) an intense narrow, line with g 1·9992 and ΔH_MS 0·035 G; (ii) a broad singlet associated with colloidal metal particles; and (iii) a triplet probably associated with ¹⁴N nuclei.

The narrow line is thought to have considerable significance since there must be rapid effective nuclear exchange in order that the expected hyperfine coupling to ¹H and ¹⁴N nuclei of the solvent be averaged almost to zero. We suggest that electron transfer between one-(e₁) and two-electron (e₂) centres: e₁+e₂⇌e₂+e₁, is rapid, even at 77 K, and that this leads to effective nuclear averaging without limiting the spin liftimes. Possible assignments for the triplet are discussed.