Nuclear Quadrupole Resonance and Stereochemistry III. Trichloromethyl derivatives

³⁵Cl nuclear quadrupole resonance frequencies are reported of the chlorine atoms in the trichloromethyl group of benzotrichlorides and trichloromethyl derivatives of heterocyclic molecules. They are compared with previously reported results for the same group attached to other planar conjugated radicals. In such compounds the three chlorine atoms cannot be equivalent and all the results are discussed from the point of view of possible orientation-dependant hyperconjugation between the C? Cl bonds and the conjugated moiety, particularly with reference to the marked effects observed in trichloromethyl ethers reported in part I of this series. In the benzo-trichloride and indeed most of the compounds discussed such effects are small.