Microwave spectrum and DFT calculations of 4,4-dimethyl-1,3-dioxane

In the microwave spectrum of 4,4-dimethyl-1,3-dioxane, the rotational transitions of a, b, and c types with J ≤ 54 are identified in the ground vibrational state of the molecule in the frequency range of 12 GHz to 37 GHz. Rotational constants, quartic centrifugal distortion constants, and the dipole moment of the molecule are determined. The revealed transitions are found to belong to the chair conformer. The B3PW91/aug-cc-pVDZ method is used to calculate the geometric parameters of 1,3-dioxane, 4-methyl-1,3-dioxane, and 4,4-dimethyl-1,3-dioxane. Alkyl substitution is shown to cause changes in the geometry of the 1,3-dioxane core.