A dodecanuclear metallamacrocycle having a multidentate bridging ligand in two different binding modes.

The reaction of Mn(OAc)2 x 4H2O with 2,6-dimethoxybenzoylsalicylhydrazide (H3dmbshz) leads to a dodecanuclear manganese metallamacrocycle [Mn12(dmbshz)12(EtOH)6], 1. The successive manganese centers are connected by the hydrazide N-N groups of the ligands in an alternating pentadentate binding mode, hexadentate binding mode. The alternation results in two alternating chelation modes around the metal centers, a tridentate-tridentate chelation mode and a bidentate-tridentate chelation mode. The metal ions in 1 are in a (A(A)Delta(B)C(A)Lambda(B))(A(A)Delta(B)C(A)Lambda(B)) chiral sequence, the alternation of the chiralities expanding the cyclic ring system to a 36-membered dodecanuclear manganese metallamacrocyclic ring system with S6 point group symmetry.