Engineering perfluoroarenes for enhanced molecular barrier effect and chirality transfer in solutions†

Abstract

Noncovalent forces have a significant impact on photophysical properties, and the flexible employment of weak forces facilitates the design of novel luminescent materials with a variety of applications. The arene-perfluoroarene (AP) force, as one type of π-hole/π interaction, shows unique directionality, involving an electron-deficient π-hole interacting with a π-electron-rich region, facilitating precise orientation and stabilization in supramolecular structures. Here we present an amination engineering protocol to build a perfluoroarene library based on an octafluoronaphthalene skeleton with various steric and electronic properties. In diluted solution-based assemblies, the perfluoroarenes perform as efficient molecular barriers to perylene building units, lighting up the luminescence. Enhanced steric effects, hydrophobicity and appended aromatic pendants are pivotal structural factors to boost the molecular barrier effect. Highly affinitive AP coassemblies transfer chirality from perfluoroarenes to achiral perylene moieties, inducing the appearance of chiral microstructures with tailored circularly polarized luminescence. Application as luminescent ink for enhanced water-resistance in displays and anti-counterfeiting is successfully realized. This work greatly extends the potential of molecular engineering in noncovalently bonded luminescent materials, and clearly reveals structure–property correlations.