Luminescence and Magnetic Properties of Two Three-Dimensional Terbium and Dysprosium MOFs Based on Azobenzene-4,4′-Dicarboxylic Linker

Abstract

Abstract:We report the in situ formation of two novel metal-organic frameworks based on terbium and dysprosium ions using azobenzene-4,4 1 -dicarboxylic acid (H 2 abd) as ligand, synthesized by soft hydrothermal routes. Both materials show isostructural three-dimensional networks with channels along a axis and display intense photoluminescence properties in the solid state at room temperature. Textural properties of the metal-organic frameworks (MOFs) have been fully characterized although no appreciable porosity was obtained. Magnetic properties of these materials were studied, highlighting the dysprosium material displays slightly frequency-dependent out of phase signals when measured under zero external field and under an applied field of 1000 Oe.

A Stable Zr(IV)-Based Metal–Organic Framework Constructed from C═C Bridged Di-isophthalate Ligand for Sensitive Detection of Cr2O72– in Water

“…The experimental results showed that H 4 sbtc had a strong emission at 445 nm, while H 4 abtc showed weak fluorescence, as illustrated in Figure S10. The H 4 sbtc ligand displays a rigid coplanar geometry resulting from the planar ethylenic bond bridging two isophthalate moieties, and therefore has a better conjugate effect in the whole structure than H 4 abtc, which has two isophthalate moieties bridged by the nonplanar diazo bond. − These results indicate that different functional groups with different configurations have an apparent influence on the fluorescence of the ligands as well as the resulting MOFs. Then, the fluorescent spectra of these two MOFs were measured.…”

Four Isostructural 3d-4f Mixed Metal Organic Frameworks and Their Magnetic Properties

“…Many MOFs that contain similar lanthanide dimers have weak ferromagnetic or antiferromagnetic interactions at cryogenic temperatures [34][35][36]. For example, Almáši et al studied the effect of solvent exchange had on the distance between the Gd 3+ ions and magnetic properties in MOF-76.…”

Trans–Cis Kinetic Study of Azobenzene-4,4′-dicarboxylic Acid and Aluminium and Zirconium Based Azobenzene-4,4′-dicarboxylate MOFs

“…Azobenzene-4,4 -dicarboxylic acid is used as an MOF linker, e.g., in azobenzenecontaining zirconium MOFs demonstrated to be effective heterogeneous catalysts for the direct amidation of benzoic acids [3]. Terbium and dysprosium MOFs with azobenzene-4,4 -dicarboxylic acid as linkers display intense photoluminescence properties in the solid-state [4]. The dynamic trans-cis photo-switching in zinc-based MOFs containing azobenzene-4,4 -dicarboxylate linkers lead to dynamic light-induced structural flexibility, which facilitates carbon dioxide capture and release [5].…”