Linear σ* and bent pseudo-π*(NCBr)– radical anions formed by ionizing radiation. An electron spin resonance study

Abstract

Exposure of solutions of cyanogen bromide to ⁶⁰Co γ-rays at 77 K resulted in the formation of linear (NC [graphic omitted] Br)^– anions having the unpaired electron almost equally distributed between the carbon and bromine orbitals, as estimated from the ¹³C and ⁸¹Br hyperfine tensor components. On warming to ca. 140 K this species was converted irreversibly into a second species having a reduced hyperfine coupling to bromine and a greatly enhanced coupling to ¹⁴N. This is identified as the bent form of (NĊBr)^–, having the unpaired electron in a pseudo-π* orbital delocalised over all three atoms.