Ligand engineering to achieve enhanced ratiometric oxygen sensing in a silver cluster-based metal-organic framework

Abstract

Ratiometric luminescent oxygen sensing based on dual fluorescence and phosphorescence emission in a single matrix is highly desirable, yet the designed synthesis remains challenging. Silver-chalcogenolate-cluster-based metal-organic frameworks that combine the advantages of silver clusters and metal-organic frameworks have displayed unique luminescent properties. Herein, we rationally introduce −NH 2 groups on the linkers of a silver-chalcogenolatecluster-based metal-organic framework (Ag 12 bpy-NH 2) to tune the intersystem crossing, achieving a dual fluorescence-phosphorescence emission from the same linker chromophore. The blue fluorescence component has a 100-nm gap in wavelength and 8,500,000-fold difference in lifetime relative to a yellow phosphorescence component. Ag 12 bpy-NH 2 quantifies oxygen during hypoxia with the limit of detection of as low as 0.1 ppm and 0.3 s response time, which is visualized by the naked eye. Our work shows that metal clusterbased MOFs have great potential in luminescent sensing, and the longer-lived chargeseparated states could find more photofunctional applications in solar energy transformation and photocatalysis.

Frontiers in circularly polarized luminescence: molecular design, self-assembly, nanomaterials, and applications

“…Metal clusters bridging molecules and nanoparticles have attracted increasing attention for the remarkable structures and fascinating chemical/physical properties [213][214][215][216][217][218].…”

Atomically precise metal nanoclusters meet metal-organic frameworks

“…The inter-nanocluster linking process remarkably improved the stability of Ag 12 NCs (from minutes to over 1 year), and a 60-fold enhancement in photoluminescence (PL, quantum yield from 0.2 to 12.1%) was observed after the assembly of Ag 12 building blocks; thus, this strategy should be promising for extension to other systems by utilizing the functionalized NCs ( Gunawardene et al., 2019 ; Li et al., 2016 ) for enhancing luminescence and catalytic functionalities ( Takano et al., 2018 ; Higaki et al., 2018 ). The composites have been utilized in various applications ( Huang et al., 2018 ; Du et al., 2018 ; Cao et al., 2019 ; Dong et al., 2020 ). Several other Ag NCs including Ag 8 ( Chang et al., 2018 ), Ag 10 ( Dong et al., 2018 ), Ag 14 ( Wang et al., 2018 ; Alhilaly et al., 2019 ; Deng et al., 2021 ), Ag 15 ( Alhilaly et al., 2019 ), Ag 18 ( Ma et al., 2019 ), and Ag 27 ( Zhao et al., 2020a ) have also been constructed into two- or three-dimensional cluster-based MOFs using N-containing linkers with different configurations and functionalities.…”

Advanced photocatalysts based on metal nanoparticle/metal-organic framework composites

“…For examples, arming MNP/MOF composite with moderate oxidation functionality, multiple catalytic sites, chiral inducing ability for partial photooxidation of methane, light-induced tandem reaction and asymmetric photocatalysis. Noteworthy, the recently developed metal-cluster based MOFs [141,142] those utilizing atomically precise metal nanoclusters as the metal nodes of MOFs have conventionally integrated the unique optical and catalytic properties of atomically precise metal nanocluster and desire more future exploitations. Fourthly, although many researches concerning on photodegradation of pollutants were reported, much more efforts are still required forwarding the practical applications.…”