A 2-Fold Interpenetrated Nitrogen-Rich Metal-Organic Framework: Dye Adsorption and CO₂ Capture and Conversion

A bifunctional ligand strategy for modification of the functional pores is of great significance in the structural design of metal-organic frameworks (MOFs). Herein, a new 2-fold interpenetrated "pillared-layer" 3D Co-MOF, {[Co(HL)(4,4'-bipy)]·DMF·2H₂O} (1), was successfully synthesized by using two kinds of ligands, imidazolecarboxylic acid and pyridine. The metal-carboxylic layers are pillared by the 4,4'-bipy ligand, displaying a 3D framework with rectangular 3D channels (high BET surface of 190.9 m² g^-1 and maximum aperture of 3.9 Å) that are decorated with abundant uncoordinated N and O atoms. 1 shows good water stability and thermal stability (320 °C). The proper pores and active sites endowed 1 with a selective adsorption of Congo red in aqueous solution. In addition, a high CO₂ adsorption capacity and an excellent CO₂ chemical conversion were observed.