Phase selectivity and tunable photophysical nature of rare earth metal–organic frameworks of EuxY1−x-PTC (H3PTC = 2, 4, 6-pyridine tricarboxylic acid; x = 0–1). Issue 42 (21st October 2020)

• Record Type: Journal Article
• Authors: Gao, Xu-Sheng; Ding, Mei-Juan; Zhang, Jin; Zhao, Li-Duo; Ren, Xiao-Ming
• Is Part Of: Dalton transactions. Volume 49:Issue 42(2020)
• Page Start: 14985
• Page End: 14994
• Publication Date: 2020-10-21
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d0dt03150j
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : All solid solutions (Eu x Y1− x -PTC, x = 0.013–0.82) are isomorphic to Eu-PTC, but different from Y-PTC, and show phase selectivity as well as excitation wavelength dependent emission. Abstract : Two rare earth metal–organic frameworks (MOFs), [Y2 (PTC)2 (H2 O)2 ]·3H2 O (Y-PTC) and [Eu2 (PTC)2 (H2 O)5 ]·H2 O (Eu-PTC) together with the solid solutions [Eu2 x Y2(1− x ) (PTC)2 (H2 O)5 ]·H2 O (Eu x Y1− x -PTC, x = 0.013–0.82), were synthesized hydrothermally, and characterized by microanalysis, IR spectroscopy, TG, powder, and single crystal X-ray diffraction techniques. Eu-PTC and Y-PTC showed different crystal structures; however, all solid solutions were isomorphic to Eu-PTC even at x = 0.013, leading to the IR spectra and TG plots of the solid solutions to be similar to those of Eu-PTC but distinct from those of Y-PTC. DFT calculations for the crystal lattice energy demonstrated that the procedure for the crystallizing nucleation of Eu-PTC occurred prior to that of Y-PTC in the reaction solution, leading to the all solid solutions being isomorphic to Eu-PTC. The solid emission spectra at ambient condition showed that Y-PTC emitted ligand-based phosphorescence at 433 nm with a quantum yield (QY) of 27.02%, while Eu-PTC and Eu x Y1− x -PTC ( x = 0.013–0.82) emitted the characteristic luminescence of Eu 3+ ions, and most solid solutions showed higher QYs than Eu-PTC; in particular, the QY of Eu0.195 Y0.805 -PTC was up to 29.48%, i.e., increased by 10% regarding Eu-PTC (19.86%). Interestingly, solid solutions with x = 0.013–0.395 showed excitation-wavelength-dependent luminescence, and such type of luminescence MOFs have promising applications including the areas of precise temperature, gas sensing and information encryption or anti-counterfeiting materials.