Walshe Catherine A, Thom Alexander J R, Wilson Claire, Ling Sanliang, Forgan Ross S
WestCHEM School of Chemistry, University of Glasgow Joseph Black Building, University Avenue, Glasgow, G12 8QQ, UK.
Advanced Materials Research Group, Faculty of Engineering, University of Nottingham University Park, Nottingham, NG7 2RD, UK.
Chemistry. 2022 Aug 26;28(48):e202201364. doi: 10.1002/chem.202201364. Epub 2022 Jun 29.
Breathing behaviour in metal-organic frameworks (MOFs), the distinctive transformation between a porous phase and a less (or non) porous phase, often controls the uptake of guest molecules, endowing flexible MOFs with highly selective gas adsorptive properties. In highly flexible topologies, breathing can be tuned by linker modification, which is typically achieved pre-synthetically using functionalised linkers. Herein, it was shown that MIL-88A(Sc) exhibits the characteristic flexibility of its topology, which can be tuned by 1) modifying synthetic conditions to yield a formate-buttressed analogue that is rigid and porous; and 2) postsynthetic bromination across the alkene functionality of the fumarate ligand, generating a product that is rigid but non-porous. In addition to providing different methodologies for tuning the flexibility and breathing behaviour of this archetypal MOF, it was shown that bromination of the formate-bridged analogue results in an identical material, representing a rare example of two different MOFs being postsynthetically converted to the same end product.
金属有机框架（MOF）中的呼吸行为，即多孔相和较少（或无）多孔相之间的独特转变，通常控制客体分子的吸收，赋予柔性MOF高度选择性的气体吸附特性。在高度柔性的拓扑结构中，呼吸作用可通过连接体修饰来调节，这通常是在合成前使用功能化连接体来实现的。在此，研究表明MIL-88A(Sc)展现出其拓扑结构的特征柔性，可通过以下方式进行调节：1）改变合成条件以生成一种刚性且多孔的甲酸支撑类似物；2）对富马酸酯配体的烯烃官能团进行后合成溴化，生成一种刚性但无孔的产物。除了提供用于调节这种原型MOF的柔性和呼吸行为的不同方法外，研究还表明，甲酸桥连类似物的溴化会产生相同的材料，这代表了两种不同的MOF后合成转化为相同最终产物的罕见例子。
