To differentiate between the transition states and educts, the C-N bond represents an effective metric, where values higher than 2.33 Å indicate an educt, while distances below 2.24 Å indicate a transition state. The educt states that do exhibit a C-N bond distance similar to that of the TS can be identified by a smaller phenyl to calixarene unit 4 oxygen atom distance (Phe-O4). When transition states exhibit a C-N bond distance over 2.33 Å, we can perform a selection based on the calixarene c0 and calixarene O5 distance (which should be greater than 11.79 Å) and the angle defined by the phenanthroline bridge, Cu and c0, where values below 110.5° indicate a TS.