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

Abstract

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 Zr6O4(OH)8(H2O)4 clusters, has been judiciously designed; the Zr6 clusters in this MOF are arranged in such a fashion that, by replacement of terminal OH(-)/H2O 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.

Structural Engineering of Low‐Dimensional Metal–Organic Frameworks: Synthesis, Properties, and Applications

“…[126,[129][130][131][132][133][134][135][136][137] Previous studies have revealed that the phase transformation of MOFs can be achieved by substitution of metal ions and ligands, as well as removal of guest molecules within MOFs. [126,[129][130][131][132][133][134][135][136][137] Previous studies have revealed that the phase transformation of MOFs can be achieved by substitution of metal ions and ligands, as well as removal of guest molecules within MOFs.…”

Linker Installation: Engineering Pore Environment with Precisely Placed Functionalities in Zirconium MOFs

“…Previously, we have demonstrated that BDC (1,4-benzenedicarboxylate) and TPDC (2',5'-dimethylterphenyl-4,4''-dicarboxylate) can be sequentially installed into PCN-700 by reacting with terminal OH − /H2O ligands through an acid-base reaction. 13 PCN-700 structure shows high degree of flexibility which can adapt to the post-synthetically installed linkers. This inspires us to explore other possible combinations of linear linkers that can be installed into PCN-700.…”

“…13 In this method, a Zr-MOF constructed from 8-connected Zr6O4(OH)8(H2O)4 clusters was selected as a matrix. Linear carboxylate linkers with various functionalities were post-synthetically installed into the matrix by replacing the terminal OH − /H2O ligands of adjacent Zr6O4(OH)8(H2O)4 clusters.…”

“…4e,15 In our previous work, we have shown that by introducing two methyl groups at the 2-and 2'-positions of BPDC (biphenyl-4,4'-dicarboxylate), a Zr-MOF with bcu bcu bcu bcu topology can be synthesized, namely PCN-700. 13 In distinct contrast to UiO-type structures with fcu fcu fcu fcu topology and 12-connected Zr6O4(OH)4 clusters, 4a PCN-700 is a bcu bcu bcu bcu net constructed from 8-connected Zr6O4(OH)8(H2O)4 clusters.…”

Photoresponsive spiropyran-functionalised MOF-808: postsynthetic incorporation and light dependent gas adsorption properties

“…24 In the present study, a novel spiropyran with a short-chain carboxylic acid (acetate) and a nitro group positioned at R 1 and R 2 , respectively, was designed and targeted (2-(3 0 ,3 0 -dimethyl-6nitrospiro-[chromene-2,2 0 -indolin]-1 0 yl)acetic acid, SP). 2a, [Zr 6 O 4 (OH) 4 -(btc) 2 (HCOO) 6 ]) was chosen as a PSM platform for the following reasons: (1) the high oxidation state of Zr IV enables strong metal-ligand bonds, making MOF-808 highly chemically robust, and thus permitting the installation and further chemical modication of the spiropyran functional groups; [27][28][29][30] (2) MOF-808 possesses sufficiently large cavities to accommodate the SP molecule (ca. 5 The zirconium-based MOF-808 25,26 (Fig.…”