Chiral Cyclic Hypervalent Iodine(III) for Halogen Bonding-Mediated Dimerization and Modulable Chirality Induction in Solution.

A challenge exists in the solution-phase construction of chiral functional materials via halogen bonding, largely due to the pronounced disruptive influence of solvation on conventional halogen bonding interactions. In this work, we describe halogen bond-mediated chirality induction in solution, enabling the construction of discrete-state chiroptical materials with tunable properties and broad substrate versatility. A central chiral site was introduced into a cyclic hypervalent iodine(III) scaffold (denoted as I(III)), which individually assembles into cationic antielectrostatic halogen-bonded dimers in the solid state and low-polarity solvents, stabilized by a quadrupled halogen and hydrogen bonding network. I(III) exhibits strong binding affinity toward both neutral and anionic halogen bond acceptors, with association constants on the order of ∼104 M-1. This robust interaction enables efficient chirality induction in both the ground and excited states. The resulting halogen-bonded complexes display solvent-responsive behavior, exhibiting mirror-image chiroptical properties in dichloromethane and tetrahydrofuran. It demonstrates excellent adaptability toward diverse halogen bond acceptors, enabling effective chirality induction across a range of systems. This versatility facilitates the realization of full-color circularly polarized luminescence.