Synthesis, Structures and Optical Limiting of Catecholato-Based Aluminum Oxo Clusters

Graphical The solvothermal synthesis of low nuclearity aluminum clusters to polynuclear aluminum clusters was achieved by regulating the amount of nitrogen-containing ligands. Present herein is the currently largest catecholato-based aluminum oxo clusters. By adjusting the amount of auxiliary 3, 5-dimethylpyrazole ligands, the synthesis of aluminum oxo clusters (AlOCs) ( AlOC-86 ) to high nuclearity AlOCs ( AlOC-88 ) were successfully achieved. Such synthetic strategy is applicable to imidazole ligands and new compounds ( AlOC-87 and AlOC-89 ) were obtained. Single crystal analysis shows that AlOC-86 and AlOC-87 are hexanuclear clusters made up of two edge-sharing tetrahedral clusters. The nuclearity of compounds AlOC-88 and AlOC-89 is doubled and they are S-shape dodecanuclear AlOCs. The aggregation of such clusters is attributed to the labile sites on the two ends of the hexanuclear clusters. In addition, open aperture (OA) Z-scan measurements results indicate that these compounds exhibit manifest reverse saturation absorption (RSA) response.