Two Terbium Metal–Organic Frameworks Showing Fluorescence Sensing and Proton Conductivity

Abstract

Two new terbium-based metal−organic frameworks, {[Tb(ADBA)-(CH 3 COO)(H 2 O)]•H 2 O} n (MOF 1) and [Tb(ADBA)(HCOO)(DMF)] n (MOF 2) (H 2 ADBA = 4,[4][5][6][7][8][9] benzoic acid), were synthesized by the solvothermal method. Structural analysis indicates that the Tb III ions in MOFs 1 and 2 are coordinated to acetic and formic acids, respectively, leading to differences in the structures. Fluorescence measurements show that both MOFs 1 and 2 are fluorescence sensors for Al 3+ and Ga 3+ with fluorescence enhancement and a blue shift. The detection limits of MOF 1 are 0.067 μM for Al 3+ and 0.093 μM for Ga 3+ , and the detection limits of MOF 2 are 0.064 for Al 3+ and 0.086 μM for Ga 3+ . The proton conductivity measurements of MOFs 1 and 2 indicate that the proton conductivities of MOFs 1 and 2 increase in resistance with increasing humidity. MOF 1 is more sensitive to humidity with a maximum conductivity of 1.07 × 10 −5 S•cm −1 under 40 °C and 98% RH. Therefore, MOFs 1 and 2 are potential multifunctional MOF materials.

Exploration of the Capacity of a Superstable Eu-MOF for Visualized Identification of 1-HP and Trp in Fresh Human Urine

“…To analyze the possible mechanism of the detection of Eu-MOF for 1-HP and Trp, PXRD patterns of Eu-MOF before and after the introduction of the analytes were captured first and shown in Figure d: all peaks in the patterns of treated samples barely have changed compared with the as-synthesized one, ruling out the occurrence of the collapse of the skeleton. , Subsequently, X-ray photoelectron spectroscopy (XPS) data were recorded for verifying whether the interaction between Eu-MOF and the analytes exists. As demonstrated in Figure b, the binding energies of Eu 3d in Eu-MOF change from 1135.04, 1164.97 eV to 1134.90, 1164.25 eV after treatment with 1-HP and to 1134.75, 1164.42 eV after sensing Trp, respectively.…”

Highly proton-conducting lanthanide metal–organic frameworks featuring highly oxygenated ligands with slow magnetic relaxation or magnetocaloric effect

“…The rise in conductivity with temperature follows the standard pattern of proton conductivity. 65–78 To explore the potential proton transport mechanisms, we calculated the activation energy ( E a ) using the Arrhenius law σ T = σ 0 exp( E a / k B T ), resulting in an E a value of 0.51 and 0.46 eV (Fig. 7b and S26, ESI†).…”