Orthogonal luminescence lifetime encoding by intermetallic energy transfer in heterometallic rare-earth MOFs

Abstract

Lifetime-encoded materials are particularly attractive as optical tags, however examples are rare and hindered in practical application by complex interrogation methods. Here, we demonstrate a design strategy towards multiplexed, lifetime-encoded tags via engineering intermetallic energy transfer in a family of heterometallic rare-earth metal-organic frameworks (MOFs). The MOFs are derived from a combination of a high-energy donor (Eu), a low-energy acceptor (Yb) and an optically inactive ion (Gd) with the 1,2,4,5 tetrakis(4-carboxyphenyl) benzene (TCPB) organic linker. Precise manipulation of the luminescence decay dynamics over a wide microsecond regime is achieved via control over metal distribution in these systems. Demonstration of this platform’s relevance as a tag is attained via a dynamic double encoding method that uses the braille alphabet, and by incorporation into photocurable inks patterned on glass and interrogated via digital high-speed imaging. This study reveals true orthogonality in encoding using independently variable lifetime and composition, and highlights the utility of this design strategy, combining facile synthesis and interrogation with complex optical properties.

Quest for Multifunctionality: Current Progress in the Characterization of Heterometallic Metal–Organic Frameworks

“…Given the broad compositional tunability of heterometallic MOFs, these materials can be further optimized to perform complex multicomponent separations in the near future. Mixed-metal MOFs can display complex, tunable luminescent signatures (Figure D). , One example, known as PCM-22, demonstrated the ability to fingerprint a range of organic solvents and quantify the concentration of H 2 O in D 2 O, which otherwise requires expensive and time-consuming analyses . This was only possible by generating mixed-metal versions of the material with variable compositions.…”

“…A trimetallic MOF based on a nonanuclear rare-earth cluster (M-1,2,4,5-tetrakis(4-carboxy- phenyl)benzene (TCPB); M = Gd, Eu, Yb) was synthesized containing various targeted ratios of Gd, Eu, and Yb (Figure 13). 46 Eu emits in the visible range, Yb emits in the near-IR (NIR) range, and Gd was used as a nonemissive spacer. The MOFs retained the anticipated visible and NIR spectral emissions, while varying amounts of Gd were found to tune the luminescent lifetimes in the visible range.…”

“…This demonstrated that direct synthesis can be a powerful tool for the formation of heterometallic MOFs, given a versatile MOF platform. Notably, similarities in size and coordination chemistry across the lanthanide series have allowed the one-pot approach to be applied broadly in the synthesis of heterometallic MOFs with rare-earth elements (REEs), including those based on polynuclear REE clusters. − …”

“…Nonanuclear cluster of EuGdYb-TCPB with varying metal ratios and associated luminescence lifetimes (T). Reprinted with permission under a Creative Commons CC-BY license from ref . Copyright 2023 Springer Nature.…”

Gold(I)-Organic Frameworks as Catalysts for Carboxylation of Alkynes with CO2

“…In virtue of structural and functional exploration, reticular chemistry endows chemists to construct targeted MOFs with specific topologies and properties by rationally choosing metal nodes and organic linkers. , For instance, incorporation of rare-earth metal produces new topologies , and largely enhances the photoluminescence (PL) properties of MOFs, , and introduction of noble metals such as Ru and Pd improves the catalytic performance of MOFs. , So far, great strides have been made in this regard, and most of the metals in the periodic table can be used as metal nodes for preparing MOFs …”