The geometry of t-butyl radicals: An ab initio study

Abstract

Ab initio calculations for the t-butyl radical, (CH₃)₃C· suggest that it is planar, and that it has a greater resistance to out-of-plane bending than has the methyl radical. The calculated isotropic hyperfine coupling to ¹³C is +36·8 G for the rigid molecule, together with +32 G for the zero-point vibratory contribution, giving a predicted total of +68·8 G. The experimental isotropic coupling of 46–51 G cannot, therefore, be taken as providing evidence for a pyramidal ground state for this radical.