Syntheses, Crystal Structures, and Photothermal Conversion Property of Aluminum Cluster Molecular Rings-Based Heterometallic Complexes

Effective combination of Al clusters with functional motif is a good way to expand the application of Al cluster materials. In this work, by introducing noble-metal ions with photothermal property into the assembly of aluminum clusters, four Al₈-based mixed metal complexes, {[Al₈Ag₂(OH)₈(NA)₁₆(CH₃CN)₂]·2SO₃CF₃}_n (Ag–Al₈, NA^– = nicotinic acid), {[(H₃O)₂Al₈Ag₃Cl₉(OH)₈(NA)₂(HNA)₁₄]·AgCl₄·Ag₂Cl₇·2SO₃CF₃}_n (AgCl-Al₈), {[Al₈Cu₄Br₃(OH)₈(NA)₁₆]·NA·HNA}_n (CuBr-Al₈-1) and {[Al₈Cu₄Br₂(OH)₈(NA)₁₆]·2NA}_n (CuBr-Al₈-2), were obtained. They are all constructed by the Al₈ ring cluster as the building unit and Ag/AgCl/CuBr-pyridine N as the linkers. Moreover, the Ag–Al₈ and AgCl-Al₈ show a photothermal conversion property under the irradiation of a 980 nm infrared laser. The temperatures of Ag–Al₈ and AgCl-Al₈ can respectively increase to 50 and 32 °C, and the photothermal conversion efficiency can reach 26.62 and 28.64%. Furthermore, the photothermal performance is reversible at least five irradiation cycles. This work first reports Al–Ag mixed metal frameworks with photothermal conversion performance based on aluminum metal clusters, enriching the family of Al cluster-based frameworks and expanding their application.