Interfacial Synthetic Approach for Constructing Metal–Organic Framework Crystals Using Metal Ion-Doped Polymer Substrate

Abstract

We report a new paradigm for the synthesis of metal−organic framework (MOF) crystals with controlled thickness by utilizing interfacial self-assembly of frameworks on metal ion-doped polymer precursors. The approach involves preparation of metal ion-doped polymer precursors through ion-exchange reactions and synthesis of MOF crystals by immersion into solutions containing organic ligands. The thickness of the resulting MOF crystals can be readily controlled by the number of doped-metal ions in the polymer precursors. MOF crystals could be very important and potentially useful for applications, and the present approach based on interfacial self-assembly could significantly advance MOF crystal preparation techniques.

Morphology Control of Metal–Organic Frameworks Based on Paddle-Wheel Units on Ion-Doped Polymer Substrate Using an Interfacial Growth Approach

“…25 In the present case of the [Cu 2 (ndc) 2 (dabco)] n framework, the formation of two-dimensional layers consisting of Cu 2+ and ndc could occur immediately after elution of the doped metal ions from the polymer substrate because the eluted metal ions and ndc ligands (deprotonated form, i.e., carboxylate anion) are closely situated around the substrate surface. After formation of the layers, dabco ligands coordinate to Cu 2+ ions in the paddle-wheel units, which results in the formation of [Cu 2 (ndc) 2 (dabco)] n crystals.…”

“…24 Recently, we have demonstrated the interfacial approach for the construction of MOF crystals using metal ion-doped polymer substrates. 25 By modifying polyimide substrate via hydrolysis to form carboxylates which can act as ion-exchangeable sites, the amount of doped metal ions in the polymer substrates could be systematically controlled. The metal ion-doped polymer substrate is used as a metal source for the MOF and induces selective self-assembly of frameworks on the polymer substrate based on the ion-exchange reaction between doped metal ions and the protons of organic ligands.…”

Synthesis of MIL-53 thin films by vapour-assisted conversion

“…53 For the RTD, a support is wetted with MOF precursor solution and the nucleation and growth of the thin-film induced by evaporation of the solvent. 54 While earlier thin-film reports used water as solvent for the synthesis of MIL-53, 12,46,47 we used DMF as reaction solvent for the RTD synthesis as DMF exhibits several advantages including higher yield 55 of the product MOF, called MIL-53(DMF) hereafter. Additionally, DMF dissolves both starting materials, Al(NO3)3•9H2O and H2BDC at room temperature, a prerequisite for the RTD approach.…”

“…aluminium sheets 46 or polyimide. 47 Vapour Assisted Conversion (VAC) is an alternative strategy for thin-film synthesis. This method is related to other methods such as the dry-gel conversion or steam-assisted conversion 48 of zeolites, covalent organic frameworks (COF) or UiO-66.…”

Formation of Metal–Organic Frameworks on a Metal Ion-Doped Polymer Substrate: In-Depth Time-Course Analysis Using Scanning Electron Microscopy

“…To overcome this problem, a sequential process of uniform nucleation on a substrate and subsequent growth of the nuclei is essential for the preparation of continuous MOF films free from cracks or intercrystalline gaps. Recently, we demonstrated an interfacial approach for the construction of MOF crystals using metal ion-doped polymer substrates as a powerful tool for obtaining MOF crystal-based films. − The approach involves the adsorption of metal ions into the polymer and the deposition of MOF crystals on the polymer substrate using a reaction solution containing only MOF ligands with microwave irradiation. The technique relies on the elution of adsorbed metal ions based on ion exchange between the adsorbed metal ions and protons of the organic ligands, leading to selective deposition of the MOF crystals on the substrates.…”