A stable mixed-valent uranium(v,vi) organic framework as a fluorescence thermometer

Abstract

Stable presence of U(V)-containing compounds is important for the study of radionuclides. However, pentavalent uranium is prone to disproportionation, thus U(V)-containing compounds are generally sensitive to air and water. Herein,...

Zwitterionic and Anionic Polycarboxylates as Coligands in Uranyl Ion Complexes, and Their Influence on Periodicity and Topology

“…Hence, in the present work, we have turned to three organic di- or trizwitterions having significant flexibility and a higher energy electronic absorption, 1,1′-[(2,3,5,6-tetramethylbenzene-1,4-diyl)­bis­(methylene)]­bis­(pyridin-1-ium-4-carboxylate) ( p L1), 1,1′-[(2,3,5,6-tetramethylbenzene-1,4-diyl)­bis­(methylene)]­bis­(pyridin-1-ium-3-carboxylate) ( m L1), and 1,1′,1″-[(2,4,6-trimethylbenzene-1,3,5-triyl)­tris­(methylene)]­tris­(pyridin-1-ium-4-carboxylate) (L2) (Scheme ), and have examined their behavior as coligands with anionic carboxylates in the formation of uranyl ion coordination polymers. Dizwitterions containing the 4-carboxylatopyridinium motif have previously been used as complexants for the uranyl cation, − in association with oxido, hydroxido, oxalato, or sulfato donors, and most often with cucurbiturils so as to form polyrotaxanes. Some of these structures involve the ligand analogous to p L1 but devoid of methyl substituents, ,, but in most cases, the pyridinium units are linked through a longer, aliphatic chain.…”

“…Dizwitterions containing the 4-carboxylatopyridinium motif have previously been used as complexants for the uranyl cation, − in association with oxido, hydroxido, oxalato, or sulfato donors, and most often with cucurbiturils so as to form polyrotaxanes. Some of these structures involve the ligand analogous to p L1 but devoid of methyl substituents, ,, but in most cases, the pyridinium units are linked through a longer, aliphatic chain. The isolation of a discrete, dinuclear species and of a diperiodic polymer containing octanuclear secondary building units (SBUs) with a ligand related to p L1 is notable and of particular relevance here in that the octanuclear species involves the association of the dizwitterion with a dicarboxylate (oxalate) .…”

Layered Uranyl Phosphonates Encapsulating Co(II)/Mn(II)/Zn(II) Ions: Exfoliation into Nanosheets and Its Impact on Magnetic and Luminescent Properties

“…When excited at 412 nm, however, almost no emission was detected for ZnU , indicating that the emission comes from the ligand‐to‐metal charge transfer transition. Temperature dependent luminescence was also observed in a few other uranyl compounds which can be used as potential luminescent thermometer [16,71–73] . By contrast, CoU and MnU are non‐emissive both at room temperature and at 77 K. This can be attributed to the presence of paramagnetic 3d metal centers which eliminate emission from uranyl complexes because of the overlap of emission from uranyl cations with the d‐d absorption band of 3d metal ions, yielding energy transfer and nonradiative decay [22,74] …”

“…Temperature dependent luminescence was also observed in a few other uranyl compounds which can be used as potential luminescent thermometer. [16,[71][72][73] By contrast, CoU and MnU are nonemissive both at room temperature and at 77 K. This can be attributed to the presence of paramagnetic 3d metal centers which eliminate emission from uranyl complexes because of the overlap of emission from uranyl cations with the d-d absorption band of 3d metal ions, yielding energy transfer and nonradiative decay. [22,74] We also measured the luminescent properties of ZnU-ns at 77 K. As shown in Figure 9a, there appear additional peaks at 508, 530, 554, 581 and 610 nm in addition to the original five peaks of the pristine ZnU.…”

Compensation effect of electron traps for enhanced fluorescence intensity ratio thermometry performance

“…Non-contact optical thermometry has become an important development trend for thermometry. [1][2][3][4][5] Specifically, the optical fluorescence intensity ratio (FIR) thermometry technique has received great attention because it avoids the fluctuations of the light sources and shows fast response and excellent resolution. [6][7][8][9][10] Therefore, developing highly sensitive FIR thermometry has become a worldwide research hotspot.…”