In addition, restraints were also applied to the guest molecules during the attach phase. Two restraints were used to control the guest translation, r and q , and one restraint to control its orientation b . Only the polar angle of the guest orientation was restrained. For these restraints, the restraint free energies were obtained by scaling force constants from l 0 to 1 over 15 windows. The free energy of releasing the restraints on the guest in the unbound state was calculated semi-analytically and included a standard-state correction at 1 M. The force constants applied to host static and guest orientational restraints are shown in Table †.