... The introduction of the lateral methyl group in series B compounds changes the molecular conformation and broadens the molecules, which decreases, the transition temperature of ... This factor is a direct result of an increase in the breath or thickness of the molecule [6161.
[Justus Liebigs Annalen der Chemie, , vol. 137, p. 89 Journal of the Chemical Society, , vol. 20, p. 64 Journal of the Chemical Society, , vol. 20, p. 19]