Sequential Linker Installation: Precise Placement of Functional Groups in Multivariate Metal-Organic Frameworks

摘要

A unique strategy, sequential linker installation (SLI), has been developed to construct multivariate MOFs with functional groups precisely positioned. PCN-700, a Zr-MOF with eight-connected Zr_6O_4(OH)_8(H_2O)_4 clusters, has been judiciously designed; the Zr_6 clusters in this MOF are arranged in such a fashion that, by replacement of terminal OH~-/H_2O ligands, subsequent insertion of linear dicarboxylate linkers is achieved. We demonstrate that linkers with distinct lengths and functionalities can be sequentially installed into PCN-700. Single-crystal to single-crystal transformation is realized so that the positions of the subsequently installed linkers are pinpointed via single-crystal X-ray diffraction analyses. This methodology provides a powerful tool to construct multivariate MOFs with precisely positioned functionalities in the desired proximity, which would otherwise be difficult to achieve.