Sequences in metal-oxo chains of multivariate metal-organic frameworks

Non-random disorder in functional materials is of particular interest as it involves a new dimension for tuning materials’ properties. Metal-organic frameworks (MOFs), an emerging class of porous materials, demonstrate complicated non-random structural features and are proven to have rich applications. However, only very few studies have been done on the non-random patterns in mixed-metal MOFs, and even fewer succeeded to analyze the bulk of the material rather than several isolated crystallites. For bimetallic MOFs hosting long metal chains, such as MOF-74, no bulk information on the metal distribution is available to date. To address this problem, we propose to determine the sequence patterns in the metal-oxo chains of mixed-metal Co/Cd- and Co/Pb-MOF-74 using bulk-sensitive element-selective EXAFS spectroscopy. The result will enable the understanding of the sequence-property relationships for the MOFs with non-random disorders and tune their syntheses for practical applications.