Schwedler Inke, Henke Sebastian, Wharmby Michael T, Bajpe Sneha R, Cheetham Anthony K, Fischer Roland A
Lehrstuhl für Anorganische Chemie II - Organometallics and Materials, Ruhr-Universität Bochum, Universitätsstraße 150, D-44801 Bochum, Germany.
Functional Inorganics and Hybrid Materials Group, Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK.
Dalton Trans. 2016 Mar 14;45(10):4230-41. doi: 10.1039/c5dt03825a.
Flexible metal-organic frameworks (MOFs) can undergo fascinating structural transitions triggered by external stimuli, such as adsorption/desorption of specific guest molecules or temperature changes. In this detailed study we investigate the potentials and limitations of tuning framework flexibility systematically by exploiting the powerful concept of mixed-linker solid solutions. We chose the prototypical family of functionalized pillared-layer MOFs of the general type Zn2(fu(1)-bdc)2x(fu(2)-bdc)(2-2x)dabco (with x = 1.00, 0.75, 0.50, 0.25 and 0.00; fu-bdc = 2,5-dialkoxy-1,4-benzenedicarboxylate with varying alkoxy chain length, dabco = 1,4-diazabicyclo[2.2.2]octane) and examined their guest responsive, as well as intrinsic temperature dependent structural flexibility by X-ray diffraction, gas physisorption and calorimetric measurements. The ratio of the different fu-bdc linkers can be adjusted freely, offering opportunity for a targeted design of these functional materials by modulating their key features, such as magnitude of framework contraction upon guest removal, breathing behaviour upon CO2 adsorption/desorption, thermoresponsive phase behaviour, and their general thermal expansivity, by the careful choice of fu-bdc linkers and their combination.
柔性金属有机框架材料（MOFs）可在外部刺激（如特定客体分子的吸附/解吸或温度变化）触发下发生引人入胜的结构转变。在这项详细研究中，我们通过利用混合连接体固溶体这一强大概念，系统地研究了调节框架柔性的潜力和局限性。我们选择了通式为Zn2(fu(1)-bdc)2x(fu(2)-bdc)(2-2x)dabco（其中x = 1.00、0.75、0.50、0.25和0.00；fu-bdc = 具有不同烷氧基链长度的2,5-二烷氧基-1,4-苯二甲酸酯，dabco = 1,4-二氮杂双环[2.2.2]辛烷）的功能化柱状层MOF原型家族，并通过X射线衍射、气体物理吸附和量热测量研究了它们对客体的响应以及固有的温度依赖性结构柔性。不同fu-bdc连接体的比例可自由调节，通过仔细选择fu-bdc连接体及其组合，为有针对性地设计这些功能材料提供了机会，可通过调节其关键特性，如客体去除时框架收缩的幅度、CO2吸附/解吸时的呼吸行为、热响应相行为及其一般热膨胀系数。
