Hydrothermal synthesis, ab-initio structure determination and NMR study of the first mixed Cu-Al fluorinated MOF

Herein, the first fluorinated heterometallic metal-organic framework (MOF) containing both Cu(II) and Al(III) cations is presented. CuAlF4.5(OH)(0.5)(H2O)[HAmTAZ](2) (HAmTAZ = 3-amino-1,2,4-triazole) was hydrothermally synthesized. The structure of this paramagnetic compound was solved using the SDPD method (structural determination by powder diffractometry) and confirmed by H-1, F-19 and Al-27 solid-state nuclear magnetic resonance (NMR) experiments. The structure (space group Ima2, a = 16.306(3) angstrom, b = 8.9356(3) angstrom, c = 8.2884(2) angstrom) can be described from the Cu-HAmTAZ layers connected by AlF5H2O octahedra, generating a three-dimensional network with a pcu topology. This compound illustrates that from 2D MOFs within the M(HTAZ)(2)(NCS)(2) (M = Mn, Fe, Co, Ni, Cu, Zn) system, insertion of AlF5H2O octahedra building units between the Cu-HAmTAZ layers provides a way to generate 3D F-MOFs.