Heptametallic Bowl-Shaped Complexes Derived from Conjugated Schiff-Base Macrocycles:  Synthesis, Characterization, and X-ray Crystal Structures

The reaction of chelating conjugated macrocycles 1a-c with Zn(OAc)2 gives bowl-shaped heptanuclear Zn complexes featuring Zn in tetrahedral, octahedral, and square-pyramidal geometries. Crystallographic and NMR results indicate that vacant Zn coordination sites within the bowl may be accessed, suggesting that these coordination complexes may be used as mimics for Zn fingers and carbonic anhydrase.