Muonium atom addition to 1,1-dimethylallene

Exposure of 1,1-dimethylallene to a beam of spin-polarised, positive muons resulted in the effective addition of muonium atoms to the central carbon atom, giving the muonated 1,1-dimethylallyl radical, Me 2 CCMu-⋯H 2 , and to the methylene carbon atom, giving the vinyl radical, Me 2 C⋯CH 2 Mu. The muon—electron hyperfine coupling constants in these radicals, and their temperature dependences, are compared with ESR data for related protic radicals.