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

Abstract

The novel interpenetrated metal–organic framework CFA-7 (Coordination Framework Augsburg University-7), [Zn₅Cl₄(tqpt)₃], has been synthesized containing the organic linker {H₂-tqpt = 6,6,14,14-tetramethyl-6,14-dihydroquinoxalino[2,3-b]phenazinebistriazole}. Reaction of H₂-tqpt and anhydrous ZnCl₂ 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 Zn²⁺ by different M²⁺ (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, CO₂ and H₂).