Spatial distribution modulation of mixed building blocks in metal-organic frameworks

Seok Jeong,Jaewoong Lim,Seung Bin Baek,Junmo Seong,Sung Wook Moon,Myoung Soo Lah,Seung Kyu Min

doi:10.1038/s41467-022-28679-w

Seok Jeong, Jaewoong Lim + Show 5 more

Open Access

https://doi.org/10.1038/s41467-022-28679-w

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Abstract

The placement of mixed building blocks at precise locations in metal–organic frameworks is critical to creating pore environments suitable for advanced applications. Here we show that the spatial distribution of mixed building blocks in metal–organic frameworks can be modulated by exploiting the different temperature sensitivities of the diffusion coefficients and exchange rate constants of the building blocks. By tuning the reaction temperature of the forward linker exchange from one metal–organic framework to another isoreticular metal–organic framework, core–shell microstructural and uniform microstructural metal–organic frameworks are obtained. The strategy can be extended to the fabrication of inverted core–shell microstructures and multi-shell microstructures and applied for the modulation of the spatial distribution of framework metal ions during the post-synthetic metal exchange process of a Zn-based metal–organic framework to an isostructural Ni-based metal–organic framework.

Highlights

The placement of mixed building blocks at precise locations in metal–organic frameworks is critical to creating pore environments suitable for advanced applications
The 1H nuclear magnetic resonance (NMR) spectrum of HBE digested in a DCl/D2O/dimethyl sulfoxide-d6 (DMSO-d6) solvent mixture confirmed the complete exchange from AP pillars to BE pillars (Supplementary Fig. 3)
The powder X-ray diffraction (PXRD) pattern of HAP obtained via Post-synthetic exchange (PSE) is identical to that of HAP obtained through the de novo solvothermal reaction (Supplementary Fig. 2)

Summary

Introduction

The placement of mixed building blocks at precise locations in metal–organic frameworks is critical to creating pore environments suitable for advanced applications. We show that the spatial distribution of mixed building blocks in metal–organic frameworks can be modulated by exploiting the different temperature sensitivities of the diffusion coefficients and exchange rate constants of the building blocks. Matzger et al reported that the post-synthetic linker exchange of MOF-5 produces core–shell microstructural MOF crystals with different degrees of linker exchange and shell thicknesses depending on the types and molecular sizes of the solvents used[31,32]. The systematic modulation of mixed building blocks can be applied for the spatial distribution of framework metal ions during the post-synthetic metal exchange process of the 3D MOF, [Zn6(BTB)4(BP)3] (ITHD(Zn), where BTB = 4,4′,4′′-benezene1,3,5-tris(benzoate)) to the isostructural 3D MOF, [Ni6(BTB)4(BP)3] (ITHD(Ni)). At lower temperatures, diffusion is faster than exchange, so kinetics-controlled pillar exchange produces uniform microstructured MOF crystals

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