A theoretical interpretation of the electron spin resonance spectrum for BH4 radicals and comparison with results for CH +4 radical cations
Abstract
Exposure of sodium borohydride to 60Co γ-rays at 77 K gave a novel radical identified as BH4 from its e.s.r. spectrum. This is dominated by a large hyperfine coupling (ca. 105 G) to two protons, but smaller couplings to two other protons and a boron atom were also detected. The proton hyperfine coupling constants are surprisingly similar to those for the recently identified CH+4 radical, which also has C2v symmetry. These results are strongly supported by ab initio calculations which confirm that such a distortion is most favourable.