Synthesis and Structural Studies of Gallium(III) and Iron(III) Hemicryptophane Complexes

Cryptophanes, with their spherical molecular cavity, are wellknown for their high propensity to form van der Waals host−guest complexes. Because of their essentially lipophilic character, the binding properties are restricted to neutral organic guests, rare gas, and ammonium salts. Recent investigations with water-soluble derivatives allowed extension of the recognition properties of cryptophane hosts to metal ions. The related hemicryptophane hosts have been designed to introduce endohedral functionalities in the molecular cavity, giving a ditopic character to these molecules.

New gallium(III) and iron(III) endohedral complexes were obtained from a hemicryptophane ligand bearing suitable binding sites for octahedral metal coordination. The solid-state structures of the free host and of the complexes were determined by single-crystal Xray diffraction analysis. The metal ion is linked to the hydrazone nitrogen and the phenolate oxygen atoms, yielding a distorted octahedral geometry around the encapsulated metal. The two isomorphous structures of the metal complexes reveal the exclusive formation of PΔ/ MΛ enantiomeric pairs.

Synthesis and Structural Studies of Gallium(III) and Iron(III) Hemicryptophane Complexes

Isabelle Gosse, Koen Robeyns, Catherine Bougault, Alexandre Martinez, Bernard Tinant, and Jean-Pierre Dutasta

 INORGANIC CHEMISTRY, 2016, Volume: 55, Issue: 3, Pages: 1011-1013.

DOI: 10.1021/acs.inorgchem.5b02750