A Series of {Al2M2} (M = Ni/Co) Clusters with Different Solvents and Auxiliary Ligands for Near-Infrared Photothermal Conversion and Aldol Condensation Reaction

By adjusting the solvents, nitrogen-containing auxiliary ligands, and transition metal salts, we successfully constructed 11 new aluminum-transition heterometallic clusters of Al2Ni2-(1-6) and Al2Co2-(1-5). They possess the same metal cores with different terminal-coordinated solvents and nitrogen-containing auxiliary ligands. Given their structural differences, we investigated the variations in the photothermal effects and aldol condensation catalytic reaction. The results indicated that the above compounds displayed a good photothermal conversion effect under 980 nm infrared laser irradiation, in which the highest temperature can rise to 161 °C (0.9 W cm-2). Nevertheless, the photothermal responses of the different Al2Ni2 clusters have no significant difference, but the Al2Ni2 clusters display a better photothermal effect than that of Al2Co2 clusters with the same structures. Interestingly, the aldol condensation reaction proves that the {Al2M2} clusters with different coordinated solvents and nitrogen-containing auxiliary ligands exhibited different catalytic activities, in which Al2Ni2-2 achieved a yield of 99%. Through bimetallic synergy and dynamic coordination assembly design, this work not only successfully realizes the structural regulation of Al-based heterometallic clusters but also demonstrates a good near-infrared photothermal conversion effect and optimizes the catalytic performance of aldol condensation reaction through structural regulation.