| Sumario: | The experimental non-zero dipole moment of trans-1,4-dicyanocyclohexane was verified through a procedure little sensitive to solute/solvent interactions. This value cannot be explained on the basis of the generally accepted centrosymmetry for trans-1,4-derivatives of cyclohexane. NMR data of both this compound and its C-1, C-4 di-deuteroderivative, as well as semi-empirical theoretical calculations with the MNDO methods show that besides a centro-symmetric form there are also low energy stable non-centrosymmetric geometries. The latter exist as a helical deformation that can account for the non-zero value of the experimental dipole moment. © 1988.
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