Partially Fluorinated Cu(I) Triazolate Frameworks with High Hydrophobicity, Porosity, and Luminescence Sensitivity

Solvothermal reactions of 3-methyl-5-trifluoromethyl-1,2,4-triazole (Hfmtz) with Cu(CH3COO)(2) at 120 degrees C in the presence of Cl- generate two partially fluorinated coordination polymers: i.e., [Cu4Cl(fmtz)(3)] (1 or MAF-51) and [Cu7Cl(fmtz)(6)] (2 or MAF-52). Single-crystal X-ray diffraction revealed 1 to have a three-dimensional (3D) nonporous structure with pcu topology consisting of 6-connected Cu-4(mu(4)-Cl) clusters and 2 to possess a highly porous (void ratio 48%) 3D bnn network consisting of 5-connected Cu-5(mu(5)-Cl) clusters. Benefiting from the hydrophobic pendant groups, complete coordination of the ligand N atoms, and strong M-N coordination bonds, 1 and 2 possess high water stability (exposed to water for at least 1 year) and hydrophobicity (water contact angles of 141 degrees and 148 degrees, respectively). The N-2 sorption isotherm of activated 2 gave Langmuir/BET surface areas of 1023/848 m(2) g(-1) and a pore volume of 0.365 cm(3) g(-1). Moreover, 2 can adsorb large amounts of benzene and methanol but barely adsorb water. Both 1 and 2 show phosphorescence of Cu(I) complexes, but only that of porous 2 is sensitive to O-2, showing a linear Stern-Volmer response below 1 mbar with an ultrahigh K-sv value of 5234 bar(-1) and ultralow limit of detection of 1.9 ppm.