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

玻璃对于我们的现代社会具有关键的技术重要性，并且在从建筑材料到显示器、光学和微电子到功能膜的领域中得到广泛的应用。传统上，玻璃分为无机玻璃（例如氧化物玻璃，如硅酸盐或硼酸盐玻璃）和有机玻璃（例如各种有机聚合物）。直到最近，才出现了一种全新的基于有机和无机建筑单元的玻璃材料。这些玻璃衍生自沸石咪唑酯框架（ZIF），金属有机框架（M0 F）的子集，由Werner型配位化学构造的网络化合物的大家族。ZIF玻璃在结构上与丰富的硅酸盐玻璃相关，然而，由于它们的有机结构单元，它们主要可以化学官能化。此外，ZIF玻璃表现出固有的微孔性，这使得它们对于气体分离和作为离子导体的应用是令人感兴趣的。ZIF玻璃相对于其结晶母体化合物的一般优点是其液相可加工性和可模塑性。然而，只有很少的ZIF被证明可以熔化和形成玻璃。在这个项目中，我们将致力于开发具有功能化有机结构单元和各种金属中心的新型ZIF玻璃。通过对新的玻璃形成ZIF的详细分析，我们还希望了解ZIF熔化和玻璃形成的化学和拓扑要求。此外，我们想要提取ZIF玻璃的质地性质（例如孔体积和孔径、气体吸附选择性）的组成-性质关系。最后，我们想要探索通过适应液相共混的原理来对ZIF玻璃进行功能化和改性的方法-该原理对于（硼）硅酸盐和聚合物玻璃是长期建立的。这将为制备具有额外功能的ZIF玻璃提供新的合成工具，例如增加的和可调的（分层）孔隙率，发光或离子电导率。

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.