The extreme steric bulk of tris (trimethylsilyl) methyl derivatives (1-X) provides interesting structural and dynamic behavior for study. Dynamic NMR studies on 1-SePh and 1-I showed restricted rotation around the C− Si bonds of each trimethylsilyl groups. An extensive multinuclear NMR study of natural abundance and 6Li and 13C enriched 1-Li revealed three species in THF-containing solvents, a dimer 1T, and two monomers, the contact ion pair ...