Molecular structure and pseudorotational motion of bromocyclopentane as determined by gas-phase electron diffraction

The molecular structure and pseudorotational motion of bromocyclopentane has been studied at a nozzle temperature of 333 K. A pseudorotational potential function of the form V(phi)=(V1/2)(1+cos phi )+(V2/2)(1+cos 2phi), where phiis the phase angle, and V1=0.74(40) kcal/mol and V2=0.42(85) kcal/mol gave the best agreement with the experimental data. The conformer with cyclopentane adopting an envelope form with thebromine atom located in the axial position is more stable than the form with the bromine located in the equatorial site by 0.74(40) kcal/mol. The thermal averaged puckering amplitude, rho , for the five-membered ring and the averaged C–C bond length were found to be 0.37(2) and 1.540(2) P, respectively.