Quartz-Like Supramolecular Glass Enabled by Host-Guest Size Mismatch.

Abstract

Supramolecular glasses are conventionally restricted by a fundamental trade-off between mechanical robustness and deep-ultraviolet (UV) transparency, due to the ubiquitous reliance on aromatic building blocks. Herein, we overcome this limitation by reporting a "quartz-like" supramolecular glass assembled from fully saturated aliphatic macrocycles and lithium salts, enabled by a host-guest size mismatch strategy. Crystallographic elucidation reveals that the undersized Li⁺ guest induces severe conformational frustration within the macrocycle, which, in concert with weak anion coordination (PF₆ ^-), kinetically suppresses crystallization. In contrast, size-matched analogues (Na⁺/K⁺) or strongly coordinating anions (Cl^-/NO₃ ^-) assemble as ordered crystalline solids. The resulting material resolves the traditional property conflict, exhibiting fused-silica-like transparency (>95%) spanning the deep-UV to near-infrared regions, while maintaining a high Young's modulus of ∼4.85 GPa, dynamic regenerative repair capability, and robust interfacial adhesion. Notably, the glass demonstrates exceptional stability against high-intensity UV and γ-ray radiation. This study establishes mismatch-induced frustration as a versatile conceptual framework for engineering optically silent supramolecular materials that decouple mechanical strength from optical bandgap.