Computationally forecasting the effect of dibenzylammonium substituents on pseudorotaxane formation with dibenzo[24]crown-8

Abstract The ability to predict the relative stabilities of analogous pseudorotaxanes is essential for the synthetic chemist yet simplified computational forecasting approaches remain scarce. Consequently, ten [2]pseudorotaxanes have been assembled (from a series of para-substituted dibenzylammonium ions and dibenzo[24]crown-8) and their experimentally-determined stabilities correlated with two computational parameters closely related to complexation energy. The strongest relationship was obtained from density functional theory calculation of binding energy (R2 = 0.92) while determination of the maximum surface electrostatic potential on the dibenzylammonium ions (a proxy indicator of complex stability) afforded comparable results (R2 = 0.88) with great reduction in computational expense.