Control of the helical chirality in octahedral complexes by a chiral macrobicyclic cavity possessing six convergent hydroxyl groups

Article abstract of DOI:10.1002/chem.19970030619

The (aR,aR,aR) and (aS,aS,aS) enantiomers of a chiral macrobicyclic ligand with a bicapped tris(binaphthol) structure were synthesized. Complexation of gallium(III), chromium(III) and iron(III) centres in the chiral cavities of these two ligands yielded exclusively one octahedral configuration in each case: the (aR,aR,aR) enantiomer gave a A complex and the (aS,aS,aS) enantiomer a Δ complex. These assignments were established by CD spectroscopy for chromium and iron centres and by molecular modelling.