Single crystal structure and photocatalytic behavior of grafted uranyl on the Zr-node of a pyrene-based metal–organic framework

Abstract

The zirconium MOF NU-1000 was post-synthetically modified through solvothermal deposition to include the uranyl ion and characterized via single-crystal X-ray diffraction; photo-oxidation was also performed.

Pyrene-based metal organic frameworks: from synthesis to applications

“…148 A color change can be observed in the samples, indicating the successful incorporation of metal species. As in the case of AIM, Zr-nodes of NU-1000 have been modified with different species; such as ions, 146,149 oxides, 141,142,145 sulfides, 143 and single-metal atoms 144,147 to date for different target applications.…”

Linker Contribution toward Stability of Metal–Organic Frameworks under Ionizing Radiation

“…Metal–organic frameworks (MOFs) are a class of hybrid porous materials based on inorganic nodes and organic linkers that have gained interest over the past 2 decades due to their diverse applications in separations, catalysis, drug delivery, and more. − Recently, the potential use of MOFs in the nuclear fuel industry specifically for capture of radionuclides, − actinide/lanthanide separations, − and use as scintillators − has drawn interest. Several studies show high capacity and selectivity for adsorption of radionuclides (I 2 , Xe, Kr, and TcO 4 – ) ,− , as well as immobilization of uranium and other actinides utilizing MOFs. ,,,− As the complexity of the challenges in the nuclear industry continue to evolve, it is imperative that versatile, radiation-resistant materials are developed and fundamentally understood.…”

Single-Atom Metal Oxide Sites as Traps for Charge Separation in the Zirconium-Based Metal–Organic Framework NDC–NU-1000

“…We elect to use the “oxy” term instead of “oxide” as a result of some ambiguity on the exact nature of the oxygenic ligands; both oxo and hydroxo species are expected to be present, as extensively discussed in other reports on Zr-MOFs. − We hypothesized that photoexcitation of the TBAPy 4– linkers within the framework would lead to charge transfer between the linker and a sufficiently proximal node-mounted transition metal atom with a number of oxo, hydroxo, and/or aqua ligands. Among conceptually similar systems are NU-1000 decorated with a ferrocene moiety (hole acceptor) or dinitrobenzene (electron acceptor) on the node , and NU-1000-supported nickel sulfide and uranyl species, which were investigated as photocatalysts; , there are also structurally similar systems that were reported to be catalytic for specific applications without the light component. , Note that these examples all position redox-active species in proximity to the TBAPy chromophore. Other examples include the observations of photoinduced charge separation in materials like ZIF-67 and MIL-100­(Fe), where the CS state can be quite long-lived.…”

“…35−37 We hypothesized that photoexcitation of the TBAPy 4− linkers within the framework would lead to charge transfer between the linker and a sufficiently proximal node-mounted transition metal atom with a number of oxo, hydroxo, and/or aqua ligands. Among conceptually similar systems are NU-1000 decorated with a ferrocene moiety (hole acceptor) or dinitrobenzene (electron acceptor) on the node 38,39 and NU-1000-supported nickel sulfide and uranyl species, which were investigated as photocatalysts; 40,41 there are also structurally similar systems that were reported to be catalytic for specific applications without the light component. 42,43 Note that these examples all position redox-active species in proximity to the TBAPy chromophore.…”