CFA-13-a bifunctional perfluorinated metal-organic framework featuring active Cu(I) and Cu(II) sites

The synthesis and crystal structure of the mixed-valent perfluorinated metal-organic framework (Me2NH2)[CFA-13] (Coordination Framework Augsburg University-13), (Me2NH2)[Cu-3(I) Cu-2(II) (tfpc)(4)] (H-2-tfpc = 3,5-bis(trifluoromethyl)-1H-pyrazole-4-carboxylic acid) is described. The copper-containing MOF crystallizes in the monoclinic crystal system within the space group P2(1)/n (no. 14) and the unit cell parameters are as follows: a = 22.3887(19), b = 13.6888(8), c = 21.1804(13) angstrom, beta = 90.495(3)degrees, V = 6491.0(8) angstrom(3). (Me2NH2)[CFA-13] features a porous 3-D structure constructed from two types of secondary building units (SBUs). Besides novel trinuclear [Cu-3(I)(pz)(4)](-) coordination units, the network also exhibits Cu(II) paddle-wheel SBUs. (Me2NH2)[CFA-13] is fully characterized by single crystal X-ray diffraction, thermo-gravimetric analysis, variable temperature powder X-ray diffraction, IR spectroscopy, photoluminescence, gas sorption measurements and pulse chemisorption experiments. M[CFA-13] (M = K+, Cs+) frameworks were prepared by postsynthetic exchange of interchannel dimethylammonium cations. Moreover, it was shown that CO molecules can be selectively bound at Cu(I) sites of [Cu-3(I)(pz)(4)](-) units, whereas Cu(II) paddle-wheel units bind selectively NH3 molecules.