Steric control of a bridging ligand for high-nuclearity metallamacrocycle formation: A highly puckered 60-membered icosanuclear metalladiazamacrocycle

Abstract

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 -(MnAMnBMnCMnDMn E)- environment, with the chiralities of the metal centers being in a rather complicated -(ΛΛΔΛΛ) (ΔΔΛΔΔ)- sequence.