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

Abstract

Precise placement of multiple functional groups in a highly ordered metal-organic framework (MOF) platform allows the tailoring of the pore environment, which is required for advanced applications. To realize this, we present a comprehensive study on the linker installation method, in which a stable MOF with coordinatively unsaturated Zr6 clusters was employed and linkers bearing different functional groups were postsynthetically installed. A Zr-MOF with inherent missing linker sites, namely, PCN-700, was initially constructed under kinetic control. Twelve linkers with different substituents were then designed to study their effect on MOF formation kinetics and therefore resulting MOF structures. Guided by the geometrical analysis, linkers with different lengths were installed into a parent PCN-700, giving rise to 11 new MOFs and each bearing up to three different functional groups in predefined positions. Systematic variation of the pore volume and decoration of pore environment were realized by linker installation, which resulted in synergistic effects including an enhancement of H2 adsorption capacities of up to 57%. In addition, a size-selective catalytic system for aerobic alcohol oxidation reaction is built in PCN-700 through linker installation, which shows high activity and tunable size selectivity. Altogether, these results exemplify the capability of the linker installation method in the pore environment engineering of stable MOFs with multiple functional groups, giving an unparalleled level of control.

Stable Metal–Organic Frameworks: Design, Synthesis, and Applications

“…Other ligands, including phosphates and sulfates, were also attached to the cluster of Zr‐MOFs by similar methods . A prominent example of dative PSM is the so‐called linker installation method in which a coordinatively unsaturated Zr‐MOF was constructed and linkers with different lengths were sequentially installed between each pair of clusters . Systematic variation of the pore volume and decoration of pore environment were realized by sequential installation of multiple linkers with different lengths or functional groups, which resulted in synergistic effects in gas uptake.…”

Improving analyte selectivity by post-assembly modification of metal–organic framework based photonic crystal sensors

“…Post-synthetic methods such as covalent and coordinative modification, deprotection, solventassisted ligand exchange or insertion provide further possibilities to precisely engineer the framework according to the desired applications. [4][5][6] These applications range from catalysis, 7 gas separation and storage, 8 to drug delivery, electrochemistry 9 and chemical sensing, 10 among many others, where post-synthetic treatment can lead to a significant improvement of the material performance. [11][12][13] When it comes to sensing applications, the stimuli-responsive material is required to exhibit a property change upon analyte exposure that can be measured as a sensing signal.…”

Stepwise Assembly of Turn‐on Fluorescence Sensors in Multicomponent Metal–Organic Frameworks for in Vitro Cyanide Detection

“…Meanwhile, a linker with a hemicyanine moiety was synthesized, denoted as L2Hcy. Previous studies have demonstrated that two linkers with lengths similar to L1 and L2Hcy can be simultaneously installed into PCN‐700 by insertion into the unsaturated Zr sites . In this work, however, it was discovered that the two linkers could not be installed simultaneously.…”

“…Herein, we report a turn‐on fluorescence sensor generated through the combination of an anthracene‐based fluorophore and a hemicyanine‐based CN − ‐responsive moiety in a multicomponent MOF (Figure ). A stable MOF with coordinatively unsaturated Zr sites, namely PCN‐700, was selected as a matrix in order to generate a multifunctional MOF . The coordinatively unsaturated sites within PCN‐700 form two types of pockets, each accommodating only one of two organic linkers, each with different lengths.…”