Catenation equilibria between ring oligomers and their relation to effective molarities: models from theories and simulations

Five models are discussed giving the equilibrium constant for the catenation of two ring oligomers as a function of their Effective Molarity (EM), the physico-chemical parameter expressing the ease of cyclization of a chain. The first three models (A–C) are derived from the revision of previous theories of catenation, that neglect excluded volume effects. A fourth model (D) is obtained from the results of Monte Carlo simulations by Deguchi and co, that can also account for excluded volume effects. Finally, a fifth model (E) is introduced which has the same functional form of models A, B, D, but is parameterized using the available experimental catenation constant.