Luminescent Properties of DOBDC Containing MOFs: The Role of Free Hydroxyls

Abstract

A novel metal−organic framework (MOF), Mn-DOBDC, has been synthesized in an effort to investigate the role of both the metal center and presence of free linker hydroxyls on the luminescent properties of DOBDC (2,5-dihydroxyterephthalic acid) containing MOFs. Co-MOF-74, RE-DOBDC (RE−Eu and Tb), and Mn-DOBDC have been synthesized and analyzed by powder X-ray diffraction (PXRD) and the fluorescent properties probed by UV−Vis spectroscopy and density functional theory (DFT). Mn-DOBDC has been synthesized by a new method involving a concurrent facile reflux synthesis and slow crystallization, resulting in yellow single crystals in monoclinic space group C2/c. Mn-DOBDC was further analyzed by single-crystal Xray diffraction (SCXRD), scanning electron microscopy−energy-dispersive spectroscopy (SEM-EDS), and photoluminescent emission. Results indicate that the luminescent properties of the DOBDC linker are transferred to the three-dimensional structures of both the RE-DOBDC and Mn-DOBDC, which contain free hydroxyls on the linker. In Co-MOF-74 however, luminescence is quenched in the solid state due to binding of the phenolic hydroxyls within the MOF structure. Mn-DOBDC exhibits a ligand-based tunable emission that can be controlled in solution by the use of different solvents.

Variability in the Formation and Framework Polymorphism of Metal‐organic Frameworks based on Yttrium(III) and the Bifunctional Organic Linker 2,5‐Dihydroxyterephthalic Acid

“…Doped yttrium (or, in fact, pure) lanthanide MOFs with 2,5‐dihydroxyterepthalic acid as organic component can show a wide variation within their optical and magnetic properties, which can be exploited in sensing and imaging applications. [ 9m,23 ] Thus, the materials reported here are a valuable expansion of the library of available compounds for research in these directions.…”

Mechanistic Insight into Charge and Energy Transfers of Luminescent Metal–Organic Frameworks Based Sensors for Toxic Chemicals

“…[240] The presence of hydroxyl group linkers in MOFs resulted in better luminescent properties with stable 3D structures. [241] MOFs with hydroxyl groups also exhibited π-π stacking and hydrogen bonding with guest NACs. The luminescence spectra of a 2,5-dihydroxy-1,4-benzenedicarboxylic acid-linked In(III)-MOF showed a rapid "turn-off" response for NACs (4-NP, 2,6-DNT, and 2,4-DNT) owing to RET and PET.…”

Kinetically Controlled Linker Binding in Rare Earth-2,5-Dihydroxyterepthalic Acid Metal–Organic Frameworks and Its Predicted Effects on Acid Gas Adsorption

“…Both modeling and experimental approaches on a set of RE elements (Y, Yb, Eu, and Tb) were used to confirm NO x binding to the linker, rather than to the metal center. , This was further verified computationally by analyzing the electronic density of states. Through the use of density functional theory (DFT), predictions have been made on target acid gas binding to the metal centers, with the gas binding energies in the order of NO 2 < H 2 O < SO 2 …”