One-Pot Formation of Large Macrocycles with Modifiable Peripheries and Internal Cavities

The shape of things to come: Aromatic oligohydrazide macrocycles with planar backbones enforced by threecenter hydrogen bonds are formed in high yield from monomeric diacid chlorides and dihydrazides. Macrocycles consisting of six metalinked pyridine and benzene residues have an internal cavity of about 10Å diameter, while those with alternating meta and paralinked benzene residues are larger and contain multiple convergent sites see picture.