Syntheses, structures and Br2 uptake of Cu(I)-bipyrazole frameworks

Abstract A novel metal-organic framework [CuCN(TMBP)·H2O]n (TCuCN) has been synthesized by the reaction of 3,3′,5,5′-tetramethyl-4,4′-bipyrazole (TMBP) and CuCN. Its structure was determined by single-crystal X-ray diffraction (SCXRD) analysis and further characterized by power X-ray diffraction (PXRD) analysis, FT-IR spectroscopy and thermogravimetric (TG) analysis. Previously reported structurally analogous TCuCl, TCuBr, TCuI have also been synthesized for Br2 adsorption comparison. All of these four MOFs exhibited reversible uptake of Br2 vapor judging by the unchanged PXRD patterns. Among four MOFs, Br2-loaded TCuI showed the most uptake amount of Br2 (15.7 ​wt%), providing the formula to be TCuI·0.33Br2. The different uptake amount of Br2 for TCuX (X ​= ​CN, Cl, Br, I) should be mainly ascribed to the intermolecular interaction between CuX and Br2.