Structure and Conformation of Trimethylamine

The ground-state rotational spectra of (CH2D) (CH3)2N, (CH3)315N, and (13CH3) (CH3)2N have been assigned yielding the effective moments of inertia. This information has been combined with that for (CH3)3N to give the following structural parameters: r(CN) = 1.451 ± 0.003 Å, r(CHs) = 1.109 ± 0.008 Å, r(CHa) = 1.088 ± 0.008 Å, ∢CNC = 110.9° ± 0.6°, ∢NCHs = 111.7° ± 0.4°, ∢NCHa = 110.1° ± 0.5°, ∢HaCHs = 108.1° ± 0.7°, ∢HaCHa = 108.6° ± 0.8°, where Hs lies in a symmetry plane. A C3υ equilibrium conformation has been established and the methyl groups appear to be tilted by 1.3° toward the unshared electron pair.