MOLECULAR RECOGNITION - EFFECT OF ROTATIONAL ISOMERS ON HOST GUEST BINDING

Monte Carlo simulations have been used to study the relative binding of dimethylurea and imidazolidone to a synthetic host molecule in CHCl3. The thermodynamic cycle-perturbation method was used to calculate the relative free energy of binding, which was compared with experimental data from NMR binding studies. Special techniques have been used to properly account for the different rotational isomeric states of dimethylurea in the thermodynamic averages. The computed relative free energy of binding DELTADELTAG = 3.6 kcal mol-1 favors the binding of imidazolidone and compares reasonably well with the experimental value of 3.1 kcal mol-1.