CFA-2 and CFA-3 (Coordination Framework Augsburg University-2 and -3) novel MOFs assembled from trinuclear Cu(I)/Ag(I) secondary building units and 3,3',5,5'-tetraphenyl-bipyrazolate ligands

The syntheses of H 2 -phbpz, [Cu 2 (phbpz)]·2DEF·MeOH ( CFA-2 ) and [Ag 2 (phbpz)] ( CFA-3 )(H 2 -phbpz = 3,3 ’ ,5,5 ’ -tetraphenyl-1 H ,1 ’ H -4,4 ’ -bipyrazole) compounds and their crystal structures are described. The Cu( I ) containing metal – organic framework CFA-2 crystallizes in the tetragonal crystal system, within space group I 4 1 / a (no. 88) and the following unit cell parameters: a = 30.835(14), c = 29.306(7) Å, V =27865(19) Å 3 . CFA-2 features a fl exible 3-D three-connected two-fold interpenetrated porous structure con- structed of triangular Cu( I ) subunits. Upon exposure to di ff erent kinds of liquids (MeOH, EtOH, DMF, DEF) CFA-2 shows pronounced breathing e ff ects. CFA-3 crystallizes in the monoclinic crystal system, within space group P 2 1 / c (no. 14) and the following unit cell parameters: a = 16.3399(3), b = 32.7506(4), c = 16.2624(3) Å, β = 107.382(2)°, V = 8305.3(2) Å 3 . In contrast to the former compound, CFA-3 features a layered 2-D three-connected structure constructed from triangular Ag( I ) subunits. Both compounds are characterized by elemental and thermogravimetric analyses, single crystal structure analysis and X-ray powder di ff raction, FTIR- and fl uorescence spectroscopy. Preliminary results on oxygen activation in CFA-2 are presented and potential improvements in terms of framework robustness and catalytic e ffi ciency are discussed.