Space Craft-like Octanuclear Co(II)-Silsesquioxane Nanocages: Synthesis, Structure, Magnetic Properties, Solution Behavior, and Catalytic Activity for Hydroboration of Ketones.

Two novel space craft-like octanuclear Co(II)-silsesquioxane nanocages, {Co8[(MeSiO2)4]2(dmpz)8} (SD/Co8a) and {Co8[(PhSiO2)4]2(dmpz)8} (SD/Co8b) (SD = SunDi; Hdmpz = 3,5-dimethylpyrazole), have been constructed from two similar multidentate silsesquioxane ligands assisted with a pyrazole ligand. The Co8 skeleton consists of eight tetrahedral Co(II) ions arranged in a ring and is further capped by two (MeSiO2)4 ligands up and down. The auxiliary dmpz- ligands seal the ring finally. Electrospray ionization mass spectrometry revealed SD/Co8a and SD/Co8b are highly stable in CH2Cl2. Magnetic analysis implies that SD/Co8a announces antiferromagnetic interactions between Co(II) ions. Moreover, both of them display good homogeneous catalytic activity for hydroboration of ketones in the presence of pinacolborane under mild conditions.