Metal imidazolate glasses from meltable zeolitic imidazolate frameworks – Fundamental understanding, porosity, functionalization & modification

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Glasses are of pivotal technological importance for our modern society and find widespread applications in areas ranging from construction materials over displays, optics and microelectronics to functional membranes. Traditionally, glasses are classified as either inorganic (e.g. oxide glasses, such as silicate or borate glasses) and organic glasses (e.g. various organic polymers). Only recently, a completely new class of glass materials based on both, organic and inorganic building units, has emerged. These glasses are derived from zeolitic imidazolate frameworks (ZIFs), a subset of metal-organic frameworks (MOFs), a large family of network compounds constructed from Werner-type coordination chemistry. The ZIF glasses are structurally related to the abundant silicate glasses, however, can principally be chemically functionalized, due to their organic building units. In addition, the ZIF glasses exhibit intrinsic microporosity, which makes them interesting for applications in gas separation and as ionic conductors. A general advantage of the ZIF glasses over their crystalline parent compounds is their liquid phase processability and moldability. However, only very few ZIFs have been demonstrated to melt and form glasses. In this project we will contribute to the development of new ZIF glasses with functionalized organic building blocks and various metal centers. By a detailed analysis of the new glass forming ZIFs, we also want to understand the chemical and topological requirements for ZIF melting and glass formation. Furthermore, we want to extract composition-property relationships for the textural properties (e.g. pore volume and pore size, gas sorption selectivity) of the ZIF glasses. Finally, we want to explore methods for ZIF glass functionalization and modification by adapting the principle of liquid phase blending – a principle, which is long established for (boro)silicate and polymer glasses. This shall provide new synthetic tools for the preparation of ZIF glasses with additional functionality, such as increased and tunable (hierarchical) porosity, luminescence or ionic conductivity.