Synthesis, structures, and CO2 sorption of a Cu(II) and Zn(II) two-fold interpenetrated pyridyl diimide metal-organic frameworks

Herein we report synthesis, structures and CO2 sorption studies of two 2-fold interpenetrated three dimensional (3D) metal-organic frameworks (MOFs) namely; {[Cu(2,6-NDC)(L1)0.5]center dot 3DMF}n (1) and {[Zn0.5(2,6-NDC)0.5(L2)0.5]center dot 2DMF}n (2) where L1 is 5,5 '-carbonylbis(2-(pyridin-3-ylmethyl)isoindoline-1,3-dione, L2 is 2,2 '- bis(pyridin-4-ylmethyl)-[5,5 '-biisoindoline]-1,1 '-3,3 '-tetraone, DMF is N,N'-dimethylformamide, and 2,6-NDC is 2,6-naphthalenedicarboxylic acid. The MOFs were synthesized solvothermally and characterized using single -crystal X-ray diffraction (SCXRD), thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD). SCXRD revealed that 1 and 2 are 3D and possess 33% and 27% of solvent-accessible volumes. Carbon dioxide sorption experiments were conducted at 195 K and 273 K on the desolvated phases of 1 (1-d) and 2 (2-d). 1-d adsorbs 11 cm3 g-1 (STP) at 273 K and 30 cm3 g-1 (STP) at 195 K, while 2-d adsorbs 35 cm3 g-1 (STP) at 273 K and 80 cm3 g-1 (STP) at 195 K.