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Representations of the two macrocyclic systems to be found in the 1. Cyclen adopts the classic [3,3,3,3] conformation (left), the 21-membered macrocycle (right) that incorporates half of the cyclen ring as well as the bridging group is more complex incorportaing five genuine corners.35 However, it can be seen that both macrocycles adopt the same conformation, defining the orientation of the amide pendant arms.
