Molecular Structure and Pseudorotation of 1,1-Dichlorocyclopentane As Determined by Gas-Phase Electron Diffraction and ab Initio Calculations: A Large Amplitude Treatment

Abstract

The molecular structure of 1,1-dichlorocyclopentane (DClCP) has been investigated by means of gas-phase electron diffraction and ab initio calculations. Although the electron diffraction data could be fairly well reproduced by a Cs (envelope) model we found it more pertinent to apply a pseudorotation model to account for the dynamic and large amplitude motion in DClCP. On the basis of this model we analyzed the dependency of the ring geometric parameters and vibrational mean amplitudes on the phase angle φ. For a better elucidation of this distinct dependency we developed particular equations which describe the dependency of the distribution of the delocalized net charges throughout the ring on the phase angle φ. The joint electron diffraction and ab initio study has led to the following ra structural parameters of DClCP (Cs conformer): r(C−Cl)ax = 1.787(3) A, r(C−Cl)eq = 1.769(3) A, average r(C−C)ring = 1.535(1) A, r(C−H)av = 1.114(5) A, ∠(C5−C1−C2) = 103.0(9)°, ∠(Cl−C−Cl) = 108.6(3)°, and ∠(H−C−H) = 10...