[N···I···N]⁺ Type Halogen-Bonding-Driven Supramolecular Helical Polymers with Modulated Chirality.

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Chirality Studies

Background:

• The [N···I···N]+ halogen bond is known for supramolecular architecture synthesis.
• Its application in helical motif construction and supramolecular chirality modulation remains unexplored.

Purpose of the Study:

• To introduce the [N···I···N]+ halogen bond for the formation of supramolecular helical polymers.
• To explore tunable supramolecular chirality in these polymers.
• To investigate methods for regulating helicity.

Main Methods:

• Utilized Ag(I) coordination to form helical structures.
• Employed pyridine-conjugated asymmetric ferrocene skeletons.
• Investigated ionic exchange and solvent effects on polymer formation and helicity.
• Performed density functional theory calculations.

Main Results:

• Successfully formed 1D double helices, 2D helicates, and 3D porous frameworks with chiral channels via Ag(I) coordination.
• Achieved 1D supramolecular helical polymers in solution driven by [N···I···N]+ halogen bonds.
• Demonstrated tunable supramolecular chirality in both coordinated and halogen-bonded polymers using Fc2.
• Observed helicity inversion in halogen-bonded polymers influenced by solvent-induced rotation of the ferrocenyl core.

Conclusions:

• The [N···I···N]+ ionic halogen bond is a novel approach for preparing supramolecular helical polymers.
• Supramolecular chirality can be effectively tuned via ion exchange and solvent environments.
• This work provides new strategies for controlling helicity in supramolecular polymers.