Morphing the Torsional Potential Energy Function from Local to Global Symmetry through a pi Link: The Rotational Spectrum of alpha,alpha,alpha-Trifluoro-p-tolualdehyde

Dynamics and inertia: The rotation of the CF3 top in alpha,alpha,alpha-trifluorotoluene becomes considerably hindered by a V3 barrier in alpha,alpha,alpha-trifluoro-p-tolualdehyde. Situated in a local V6 environment, the V3 barrier is caused by the aldehyde group and communicated through the aromatic pi system. Quite dramatically, the ground state inertial defect jumps from -1.271 to -89.961 uÅ2, thus reflecting the electronically induced rigidity.