The subtle structural difference between meso-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (tet-a) (L1) and c-rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (tet-b) (L2) is responsible for different methods of metal binding. Conformational studies show that steric interactions limit the flexibility of tet-a (L1) thus increasing the strain energy of the folded forms of macrocycle. Conformational searches are not normally undertaken in inorganic molecular mechanical calculations but this work shows them to be of vital importance.