Supramolecular asymmetric induction in dinuclear triple-stranded helicates

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Chiral Induction

Background:

• Supramolecular chiral induction typically relies on chiral building blocks.
• Dinuclear triple-stranded helicates are complex structures with potential for chirality.
• Achiral components present a challenge for creating enantiomerically enriched supramolecular systems.

Purpose of the Study:

• To investigate supramolecular chiral induction using achiral components.
• To explore the effectiveness of chiral cations in inducing enantiomeric enrichment.
• To elucidate the mechanism of intermolecular chiral induction in a specific cation-helicate complex.

Main Methods:

• Synthesis of five dinuclear triple-stranded helicates from achiral components.
• Treatment of racemic helicate mixtures with three different chiral cations.
• Spectroscopic analysis including circular dichroism (CD) spectroscopy.
• Structural determination via X-ray crystallography.
• Mechanistic investigation using one and two-dimensional NMR spectroscopy.

Main Results:

• Observation of supramolecular chiral induction in helicates formed from achiral components.
• Demonstration that three distinct chiral cations effectively induce high enantiomeric enrichment.
• Elucidation of the intermolecular chiral induction mechanism for the N-methyl-s-nicotinium/K6[Ga2L(1)3] system.

Conclusions:

• Achiral components can be utilized to create supramolecular helicates capable of chiral induction.
• Chiral cations serve as potent agents for enantiomeric enrichment of these helicates.
• The study provides a detailed mechanistic understanding of intermolecular chiral induction in these systems.