Successful Predictions of the Residual Motion of Weakly Associated Species as a Function of the Bonding between Them

We demonstrate the utility of a specific form of a relationship between the bonding (enthalpy change) and restriction in motion (entropy change) for weak associations. This utility is illustrated through an analysis of a collection of thermodynamic data for the interaction of macrocycles with neutral molecules (both in most cases with limited abilities to change their internal motions) in nonpolar media. By inspection of the data in comparison to the trend that would be expected from this enthalpy/entropy compensation curve, we have successfully identified those points that either represent mistakes in transcription of data from the original or incorrect measurements or in the context of the discussion must be represented as associations rather than dissociations.