Glass formation of metal organic-inorganic complexes.

Some metal organic-inorganic complexes (MOICs) are known for their glass-forming ability. However, the composition range of glass-forming MOICs is rather limited as the mechanism of MOIC glass formation has not been well understood. Here, we uncover the structural factors controlling MOIC glass formation and thereby develop new MOIC glass formers. MOIC glass formation relies on the creation of a hydrogen-bonded structural network. By properly choosing metal centers, anions, and organic ligands of MOICs, a supramolecular structural network can be constructed, thereby allowing property modulation. Furthermore, MOIC systems with mixed crystals are generated by ligand-mixing and then vitrified by melt-quenching. The glass-transition temperature (T g) of the derived glasses can be linearly tuned through the substitution of benzimidazole for imidazole. Interestingly, vitrification led to disordering of hydrogen-bonded networks in MOICs at short-, medium-, and long-range scales. This work enables the expansion of the composition range of MOIC glasses with various functionalities.