A continuous chirality analysis of homoleptic hexacoordinated complexes

Hexacoordinated complexes are generally considered to be potentially chiral if they have either at least two bidentate ligands or at least three diffe rent monodentate ligands. Here we draw attention to a neglected general pos sibility, namely that homoleptic hexacoordinated complexes with molecular s tructures in between octahedral and trigonal prismatic, following the Baila r twisting route, are chiral. A quantitative evaluation of the degree of ch irality of such hexakis(mondentate) complexes shows that they reach maximum chirality when the trigonal rotation angle of the prism reaches 23 degrees . Model calculations and analysis of experimental X-ray structures are in g ood agreement. The most chiral of the complexes with monodentate ligands th at have been analyzed is [Zr(SC6H4-4-OMe)(6)](2-). The validity of the theo retical prediction is also corroborated by an analysis of the chirality of the coordination sphere in twisted tris(chelate) complexes.