CFA-7 : an interpenetrated metal–organic framework of the MFU-4 family

Abstract

Structural characterization of a novel interpenetrated bistriazolate-based MOF followed by postsynthetic replacement of Zn 2+ by M 2+ ions (M = Co, Ni, Cu) represents a versatile approach towards redox-active MOFs. The novel interpenetrated metal–organic framework CFA-7 (Coordination Framework Augsburg University-7), [Zn 5 Cl 4 (tqpt) 3 ], has been synthesized containing the organic linker {H 2 -tqpt = 6,6,14,14-tetramethyl-6,14-dihydroquinoxalino[2,3- b ]phenazinebistriazole}. Reaction of H 2 -tqpt and anhydrous ZnCl 2 in N , N -dimethylformamide (DMF) yields CFA-7 as pseudo-cubic crystals. CFA-7 serves as precursor for the synthesis of isostructural frameworks with redox-active metal centers, which is demonstrated by postsynthetic metal exchange of Zn 2+ by different M 2+ (M = Co, Ni, Cu) ions. The novel framework is robust upon solvent removal and has been structurally characterized by single-crystal X-ray diffraction, TGA and IR spectroscopy, as well as gas sorption (Ar, CO 2 and H 2 ).