Highly selective C2H2 and CO2 capture and magnetic properties of robust Co-chain based metal–organic framework

A robust Co-based metal–organic framework, [Co3(L)(OH)2(H2O)4]∙2DMF∙2H2O (1), was synthesized under solvothermal conditions using pyridyl-decorated tetracarboxylic acid, 2,6-di(2',5'-dicarboxylphenyl)pyridine (H4L). Structural analysis demonstrates that 1 is a 3D framework based on 1D alternate Co4 chain units. The desolvated structure of 1a contains 1D open channels with a highly polar pore surface decorated with open metal sites, μ3-OH group and pyridyl group sites, exhibiting multipoint interactions between C2H2 and CO2 molecules. The framework efficiently uptakes C2H2 and CO2 with significant selectivity for C2H2 and CO2 over CH4. In addition, the magnetic properties of 1 were investigated, which showed a slow freezing process.