Tuning Magnetic and Photophysical Properties of Luminomagnetic Metal‐Organic Framework Composites in an Inverse Core‐Satellite Structure

• Published in: ChemPlusChem (Weinheim, Germany) Vol. 88; no. 2; pp. e202200395 - n/a
• Main Authors: Seuffert, Marcel T., Granath, Tim, Kasper, Thomas, Maile, Ruben, Pujales‐Paradela, Rosa, Prieschl, Johannes, Wintzheimer, Susanne, Mandel, Karl, Müller‐Buschbaum, Klaus
• Format: Journal Article
• Language: English
• Published: Germany 01.02.2023
• Subjects: composites; core-shell nanostructures; luminescence; magnetism; metal-organic frameworks; composites; magnetism; luminescence; core-shell nanostructures; metal-organic frameworks
• ISSN: 2192-6506; 2192-6506
• DOI: 10.1002/cplu.202200395

Luminomagnetic composites have been synthesized that allow for an individual tuning of luminescence intensity, chromaticity and magnetization by combination of superparamagnetic, citrate‐stabilized iron oxide nanoparticles with the luminescent MOFs 3∞[Ln2(BDC)3(H2O)4] (Ln=Eu, Tb; BDC2−=terephthalate). The components are arranged to a concept of inverse structuring compared to previous luminomagnetic composites with MOF@magnetic particle (shell@core) composition so that the luminescent MOF now acts as core and is covered by magnetic nanoparticles forming the satellite shell. Thereby, the magnetic and photophysical properties are individually tuneable between high emission intensity (1.2 ⋅ 106 cps mg−1) plus low saturation magnetization (6 emu g−1) and the direct opposite (0.09 ⋅ 106 cps mg−1; 42 emu g−1) by adjusting the particle coverage of the MOF. This is not achievable with a core‐shell structure having a magnetic core and a dense MOF shell. The composition of the composites and the influence of different synthesis conditions on their properties were investigated by SEM/EDX, PXRD, magnetization measurements and photoluminescence spectroscopy. Luminomagnetic, inverse core‐satellite composites redundant were generated by combination of luminescent lanthanide‐containing MOFs with citrate‐stabilized iron oxide nanoparticles. The properties luminescence intensity, chromaticity, and magnetization can be individually steered and tuned by adjusting the ratio of the components. The composites are highly stable against solvents, pH, ultrasonication, and allow for magnetic separation.