6+6 Macrocycles derived from 2,6-diformylpyridine and trans-1,2-diaminocyclohexane

While the non-templated reaction of racemic trans-1,2-diaminocyclohexane with 2,6-diformylpyridine leads to a mixture of 2 + 2 and 4 + 4 macrocyclic imines, the reaction of the isolated 2 + 2 macrocycle with cadmium(II) chloride results in the fusion of three smaller macrocyclic units into a large 6 + 6 macrocycle. The X-ray molecular structures of the hexanuclear cadmium complex of this macrocycle as well as the derived 6 + 6 protonated amine reveal multiply folded macrocycles that adopt container-type conformations. (C) 2018 Elsevier Ltd. All rights reserved.