Novel 48-membered hexadecanuclear and 60-membered icosanuclear manganese metallamacrocycles

Either an S₈ symmetrical 48-membered hexadecanuclear or an S10 symmetrical 60-membered icosanuclear manganese metallamacrocycle was self-assembled using a manganese ion and a ditopic pentadentate ligand. This was either N-4-phenylbenzoylsalicylhydrazide (H₃pbshz) containing a rigid rod-shaped, bulky biphenyl residue as a terminal N-acyl group or N-3,3-diphenylpropionylsalicylhydrazide (H₃dppshz) containing a flexible β-branched N-acyl group, but with two sterically bulky phenyl residues at the Cβ position. The backbone of these metal-organic assemblies is a repeating unit consisting of a -[Mn-N-N-] link that extends to complete either the 48-membered cyclic structure involving 16 manganese(III) centers and 16 ditopic linker ligands or the 60-membered cyclic structure involving 20 manganese(III) centers and 20 ditopic linker ligands (depending on the ligand used). Even though the nuclearity of the metallamacrocycles was different, the successive manganese centers were in the same chiral sequence, ⋯(ΛΛΔΔ)(ΛΛΔΔ) ⋯.