Solely 3-Coordinated Organic-Inorganic Hybrid Copper(I) Halide: Hexagonal Channel Structure, Turn-On Response to Mechanical Force, Moisture, and Amine.

Herein, we report a novel organic-inorganic hybrid Cu I halide PyCs 3 Cu 2 Br 6 (Py: pyridinium), where pyridinium and cesium ions coexist. We successfully develop a novel strategy for fabricating turn-on responsive materials. PyCs 3 Cu 2 Br 6 has a higher single-crystal symmetry (no. 191) than its all-inorganic counterpart Cs 3 Cu 2 Br 5 (no. 62), and the incorporation of organic pyridinium varied the coordination environment of Cu I . PyCs 3 Cu 2 Br 6 formed a triangle planar structure with solely 3-coordinated Cu I ions, which quenched its luminescence. However, PyCs 3 Cu 2 Br 6 presented a hexagonal channel structure, which enabled it with turn-on response upon mechanical force, heat, moisture, and amine vapor. Such structure offered channels for active molecules to diffuse and interact with pyridiniums, leading to the stimuli-triggered phase change to highly emissive Cs 3 Cu 2 Br 5 . To our best knowledge, for the first time, we discover a novel 3-coordinated organic-inorganic hybrid Cu I halide with turn-on response to external stimuli. We believe that our study will contribute to expanding the landscape of smart stimulus-responsive materials and lay the foundation for their wide applications.