Macrocycles Incorporating an Endocyclic But Non‐Sterically‐Hindering Chelate: Synthesis and Structural Studies

Two rings of different size have been prepared both incorporating a 3,3′‐biisoquinoline (biiq) chelate. The biiq ligand bears phenyl groups at its 8‐ and 8′‐positions, which provide it with an approximate crescent shape. The incorporation of the 8,8′‐diaryl‐3,3′‐biisoquinoline motif in a ring leads to an unusual situation. The complexing site of the macroring is unambiguously pointing towards the inner part of the macrocycle, but, at the same time, it is not sterically hindered, due to the relatively large distance between the coordinating site and the various organic groups belonging to the macrocyclic structure. The synthesis of the two compounds is reported, as well as the X‐ray structure of one of them, which confirms the expected geometrical properties of the molecules.