| Abstract: By controlling the molar ratio of solvent compositions in DMSO/DMF/H2O solvent and reaction temperature, three Co-cluster-based metal-organic frameworks, (NH2Me2)2[Co3O(BTB)2(H2O)]·2H2O·4.5DMF·7.5DMSO (1), (NH2Me2)2[Co4O(BTB)8/3]·6H2O·13DMSO (2) and (NH2Me2)2[Co6O3(BTB)8/3(H2O)4]·5H2O·5DMF·13DMSO (3), (BTB, 4,4′,4″-benzene-1,3,5-triyl-tribenzoate), have been synthesized based on H3BTB and cobalt chloride, containing trinuclear Co3O, tetranuclear Co4O and hexanuclear Co6O3 cluster, respectively. The hexanuclear Co-O cluster is observed unprecedentedly. Systematic researches indicate that relatively moderate temperature, 105 ℃, and more DMF used could facilitate the formation of trinuclear cluster while high temperature, 125 ℃, and DMSO solvent may be in favor of the construction of tetranuclear cluster. However, lower temperature, 95 ℃, and more water may contribute to the generation of hexanuclear cluster. In addition, the transformation of 1 to 3 in mother liquid happened when exposed in atmosphere at room temperature. Interestingly, 2 and 3 exhibit the identical framework with topological type of the and the Schlfli symbol of (43)8(48.64.812.104)3. Furthermore, the adsorption properties of the evacuated products of 2 and 3 have been investigated and both of them have relatively high H2 adsorption enthalpy. CCDC: 867443, 1; 867444, 2; 867445, 3. |
