Chiral lanthanide-silver() cluster-based metal-organic frameworks exhibiting solvent stability, and tunable photoluminescence

Due to the lack of effective synthetic strategies, the preparation of chemically stable chiral Ag( i ) cluster-based materials for assembly remains challenging. Here, we have developed an approach to synthesize three pairs of chiral Ln-Ag( i ) cluster-based metal-organic frameworks (MOFs) named l -LnAg 5 -3D (Ln = Gd for 1- L , Eu for 2- L , and Tb for 3- L ) and d -LnAg 5 -3D (Ln = Gd for 1- D , Eu for 2- D , and Tb for 3- D ) by employing a chiral Ag( i ) cluster ({Ag 5 S 6 }) as the node and Ln 3+ ion as the inorganic linker. Structural analysis revealed that the chiral ligands induced chirality through the entire structure, resulting in a chiral helix arrangement of the C 3 -symmetric chiral {Ag 5 S 6 } nodes and Ln 3+ ions. These compounds showed high solvent stability in various polar organic solvents. The solid-state circular dichroism (CD) spectra of compounds l -LnAg 5 -3D and d -LnAg 5 -3D exhibited obvious mirror symmetrical peaks. The emission spectra in the solid state revealed that compound 1- L only exhibited the emission peak of {Ag 5 S 6 }, while compounds 2- L and 3- L exhibited overlapping peaks of Ln 3+ and {Ag 5 S 6 } at different excitation wavelengths. This demonstrates the tunable photoluminescence from {Ag 5 S 6 } to Ln 3+ by introducing different Ln 3+ ions and manipulating the excitation wavelengths. The study underscores the enhanced stability of Ag( i ) cluster-based MOFs achieved through the incorporation of Ln 3+ ions and establishes chiral Ln-Ag( i ) cluster-based MOFs as promising candidates for advanced materials with tunable photoluminescence. Three pairs of chiral Ln-Ag(I) cluster-based MOFs showed the desired tunable photoluminescence from {Ag 5 S 6 } to Ln 3+ by introducing Ln 3+ ions with different emission band and controlling different excitation wavelengths.