A polyhedron-based metal-organic framework with a rare hexanuclear Co(II) cluster for selective sorption and chemical conversion for CO2

A new polyhedron-based metal-organic framework (MOE), namely {[Co-6(OH)(2)(H2O)(4) (cpt)(9)](NO3)(DMF)(13)} (1, Hcpt = 4-(4'-carboxyphenyl)-1,2,4-triazole), was constructed by employment of a bifunctional triazolyl-carboxyl ligand Hcpt. Single crystal X-ray structural analysis shows that compound I features a rare hexanuclear {Co-6(OH)(2)(H2O)(6)}(10+) cluster and could be topologically viewed as a 10-connected bct net. Furthermore, compound 1 comprises octahedral cages with the inner diameter of 19.6X12.9 angstrom(2) and 2D pore systems along the a and b axis with high density of open metal centers generated by the removal of coordinated water molecules, which contribute to a high CO2 adsorption capacity and significantly selective capture for CO2 over CH4 around room temperature. In addition, the resulting activated la could behave as the heterogeneous Lewis catalyst facilitates the chemical fixation of CO2 coupling with epoxides into cyclic carbonates under mind conditions.