The complexation kinetics of Na+ with the D3d and Ci conformations of 18-crown-6 are studied by using canonical variational transition-state theory. Reaction path properties and the complexation rate constant are calculated for each of these conformations. In canonical variational transition-state theory the transition state is located at the point on the reaction path where the free energy is a maximum. The calculations are performed by using a model analytic potential energy function that represents the Na+ + crown intermolecular potential and the crown intramolecular potential. The reaction path is found by following the path of steepest descent on the analytic potential energy surface. Reaction path properties studied include the potential energy, the attenuation of the transitional mode vibrational frequencies, harmonic oscillator and hindered rotor treatments of the transitional modes, conformational changes of the crown during the complexation process, and the asymptotic vibrational frequencies of the complexed and uncomplexed crown.