Self-Sorting Chiral Subcomponent Rearrangement During Crystallization

The incorporation of enantiopure 1-amino-2,3-propanediol as a subcomponent into a dicopper
double helicate resulted in perfect chiral induction of the helicate's twist. DFT calculations allowed the
determination of the helicity of the complex in solution. The same helical induction, in which S amines
induced a Λ helical twist, was observed in the solid state by X-ray crystallography. Electronic structure
calculations also revealed that the unusual deep green color of this class of complexes was due to a metal-to-ligand charge transfer excitation, in which the excited state possesses a valence delocalized Cu23+ core.
The use of a racemic amine subcomponent resulted in the formation of a dynamic library of six
diastereomeric pairs of enantiomers. Surprisingly, this library converted into a single pair of enantiomers
during crystallization. We were able to observe this process reverse upon redissolution, as initial ligand
exchange was followed by covalent imine metathesis.