Schneemann Andreas, Rudolf Robin, Baxter Samuel J, Vervoorts Pia, Hante Inke, Khaletskaya Kira, Henke Sebastian, Kieslich Gregor, Fischer Roland A
Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, D-85748 Garching, Germany and Catalysis Research Centre, Technische Universität München, Ernst-Otto-Fischer Straße 1, 85748 Garching, Germany.
Dalton Trans. 2019 May 15;48(19):6564-6570. doi: 10.1039/c9dt01105f.
Flexible metal-organic frameworks (MOFs) exhibit large potential as next-generation materials in areas such as gas sensing, gas separation and mechanical damping. By using a mixed metal approach, we report how the stimuli reponsive phase transition of flexible pillared-layered MOFs can be tuned over a wide range. Different Cu2+ to Zn2+ metal ratios are incorporated into the materials by using a simple solvothermal approach. The properties of the obtained materials are probed by differential scanning calorimetry and CO2 sorption measurements, revealing stimuli responsive behaviour as a function of metal ratio. Pair distribution functions derived from X-ray total scattering experiments suggest a distortion of the M2 paddlewheel as a function of the Cu content. We rationalize these phenomena by the different distortion energies of Cu2+ and Zn2+ ions to deviate from the square pyramidal structure of the relaxed paddlewheel node. Our work follows on from the large interest in tuning and understanding the materials properties of flexible MOFs, highlighting the large number of parameters that can be used for the targeted manipulation and design of properties of these fascinating materials.
柔性金属有机框架材料（MOFs）在气体传感、气体分离和机械阻尼等领域作为下一代材料展现出巨大潜力。通过采用混合金属方法，我们报告了如何在很宽的范围内调节柔性柱状层状MOFs的刺激响应相变。通过简单的溶剂热法将不同的Cu²⁺与Zn²⁺金属比例引入材料中。通过差示扫描量热法和CO₂吸附测量对所得材料的性能进行了探究，揭示了刺激响应行为与金属比例的关系。从X射线全散射实验得出的对分布函数表明，M₂桨轮的畸变是Cu含量的函数。我们通过Cu²⁺和Zn²⁺离子偏离松弛桨轮节点的四方锥结构的不同畸变能量来解释这些现象。我们的工作是基于对调节和理解柔性MOFs材料性能的极大兴趣展开的，突出了可用于有针对性地操纵和设计这些迷人材料性能的大量参数。
