Dysprosium(III) Metal–Organic Framework Demonstrating Ratiometric Luminescent Detection of pH, Magnetism, and Proton Conduction

Abstract

A multifunctional metal–organic framework, (Hdmbpy)­[Dy­(H2dobdc)2(H2O)]·3H2O (Dy-MOF, H4dobdc = 2,5-dihydroxyterephthalic acid, dmbpy = 4,4′-dimethyl-2,2′-bipyridine), was synthesized and structurally characterized. The metal center DyIII is connected by four carboxyl groups to form the [Dy2(CO2)4] binuclear nodes, which are further interconnected by eight separate H2dobdc2– ligands to form a three-dimensional (3D) framework including hydrophilic triangular channels and abundant hydrogen-bonding networks. Dy-MOF has good stability in aqueous solution as well as in harsh acidic or alkaline solutions (pH range: 2.0–12.0). Furthermore, the luminescence signal of Dy-MOF undergoes a visualized color change as the acidity of the solution alters, which is the typical behavior of pH ratiometric probe. At a 100% relative humidity, Dy-MOF exhibits a high proton conductivity σ (1.70 × 10–4 S cm–1 at 303 K; 1.20 × 10–3 S cm–1 at 343 K) based on the proton hopping mechanism, which can be classified as a superionic conductor with σ exceeding 10–4 S cm–1. Additionally, the ferromagnetic interaction and magnetic relaxation behavior are simultaneously achieved in Dy-MOF. Herein, the combination of luminescence sensing, magnetism, and proton conduction in a single-phase 3D MOF may offer great potential applications in smart multitasking devices.

Supramolecular encapsulation of hexaaquacobalt(ii) cations in a hydrogen-bonded framework for slow magnetic relaxation and high proton conduction

“…Recently, several lanthanide based molecular nanomagnets have been reported for proton conduction as emerging bifunctional magnetic materials. 32–35 Herein, the supramolecular architecture showing both magnetic and electrical functions is distinct from these reported systems based on structural and synthetic viewpoints.…”

An Overview of the Design of Metal-Organic Frameworks-Based Fluorescent Chemosensors and Biosensors

“…The abnormal intracellular pH is related to many diseases, such as cancer, stroke, and Alzheimer’s disease [ 82 ]. Several fluorescent MOFs have been reported to exhibit response toward different pH values, such as PCN-225(Zn), Y(III)-MOFs and Dy-MOF [ 83 , 84 , 85 , 86 , 87 ]. Typically, Chen et al reported a dual-emission fluorescent MOF for monitoring the change of pH value with an excitation wavelength ( Figure 4 ) [ 88 ].…”

Two heptanuclear cluster-based 3D metal–organic frameworks with a good magnetocaloric effect

“…[1][2][3][4][5][6][7] As we know, two prominent representative applications of molecule-based magnetic materials are single molecule magnets (SMMs) and the magnetocaloric effect. [8][9][10][11][12][13][14][15][16] Warburg made the first observation of the magnetocaloric effect (MCE) in metal iron in 1881. He measured it via the change in isothermal magnetic entropy ΔS m which is based on the equation: nR ln(2S + 1)/M w .…”