Steric Control of a Bridging Ligand for High-Nuclearity Metallamacrocycle Formation: A Highly Puckered 60-Membered Icosanuclear Metalladiazamacrocycle

A novel S4-symmetric icosanuclear manganese metalladiazamacrocycle was synthesized using a pentadentate ligand, N-3-phenyl-trans-2-propenoylsalicylhydrazide (H3L), that has a rigid and bulky
terminal N-acyl group. A 20 cyclic repeat of an −(Mn−N−N)−
linkage resulted in a highly puckered diaza-bridged 60-membered
icosanuclear metallamacrocycle. The steric interaction between the
ligands in the cyclic system leads to five consecutive MnIII centers
in a chemically different −(MnAMnBMnCMnDMnE)− environment, with
the chiralities of the metal centers being in a rather complicated
−(ΛΛΔΛΛ)(ΔΔΛΔΔ)− sequence.