Reticulating node-linker-modulator chemical spaces for modular design of alkoxide-based glasses and liquids.

Glasses linked by molecular building blocks are emerging materials promising for combining the processability of glasses and designability of reticular frameworks. Achieving modular chemical space construction is key to promoting structural diversity for these glasses, which requires systematically understanding their structures and properties. Herein, we combine rheological, thermal, compositional and total scattering techniques to study glasses and liquids based on titanium, zirconium and boron nodes, multi-dentate alcohol linkers and monodentate alcohol modulators and elucidate their structure-property relationships. With decreasing modulator, the node-linker-modulator series show increased connectivity characterized by increased viscosity and diminished heat capacity jump at glass transition, eventually giving glassy coordinative networks. By systematically tuning their compositions, we show the glass transition temperatures of these materials are affected by the interplay between non-covalent interactions and covalent network formation. The modular designability in alkoxide-based glasses is exploited for synthesizing fluorescent molecular network-forming glasses with high quantum yield, which can be integrated into electroluminescent devices. The current development represents an important expansion of reticular chemistry into the regime of glassy materials.