Massive Anisotropic Thermal Expansion and Thermo-Responsive Breathing in Metal-Organic Frameworks Modulated by Linker Functionalization
Massive Anisotropic Thermal Expansion and Thermo-Responsive Breathing in Metal-Organic Frameworks Modulated by Linker Functionalization
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DOI：
10.1002/adfm.201301256
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发表时间：
2013-12-23
影响因子：
19
通讯作者：
Fischer, Roland A.
中科院分区：
文献类型：
--
作者：
Henke, Sebastian;Schneemann, Andreas;Fischer, Roland A.
通式[Zn-2(fu-L)(2)dabco](n)功能化金属有机骨架（fu-MOFs）表现出前所未有的大单轴正负热膨胀（fu-L =烷氧基功能化1,4-苯二羧酸酯，dabco = 1,4-重氮杂环[2.2.2]辛烷）。体积热膨胀的大小更类似于液态水的性质，而不是任何晶体固态材料的性质。fu-L的烷氧侧链连接到骨架上，但仍然表现出很大的构象灵活性。这些侧链的热诱导运动引起极大的各向异性框架膨胀，并最终引发可逆的固态相变到急剧膨胀的结构。这些杂化固液材料的热响应性能是由full - ls的选择和组合精确控制的，并取决于功能部分和链长。原则上，这种组合方法允许有针对性地设计mof的极端热机械性能，解决晶体固体物质和液态之间的状态。
Functionalized metal-organic frameworks (fu-MOFs) of general formula [Zn-2(fu-L)(2)dabco](n) show unprecedentedly large uniaxial positive and negative thermal expansion (fu-L = alkoxy functionalized 1,4-benzenedicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]octane). The magnitude of the volumetric thermal expansion is more comparable to property of liquid water rather than any crystalline solid-state material. The alkoxy side chains of fu-L are connected to the framework skeleton but nevertheless exhibit large conformational flexibility. Thermally induced motion of these side chains induces extremely large anisotropic framework expansion and eventually triggers reversible solid state phase transitions to drastically expanded structures. The thermo-responsive properties of these hybrid solid-liquid materials are precisely controlled by the choice and combination of fu-Ls and depend on functional moieties and chain lengths. In principle, this combinatorial approach allows for a targeted design of extreme thermo-mechanical properties of MOFs addressing the regime between crystalline solid matter and the liquid state.