Aliphatic rings are present in 70.4% of the centroids, and 4.6% of these centroids contain macrocyclic rings (defined as having 12 or more atoms) , . This would add flexibility to the molecules. Due to out-of-plane bending (pseudo-rotations), known as ring puckering, flexible rings can have different conformations. Factors such as endocyclic double bonds, the nature of substituents, changes in exocyclic functionality, especially in macrocycles, control the conformational flexibility of rings and can lead to significant conformational changes. It would be difficult to predict such changes as the coupled ring bond rotations are not well studied .