New isoreticular phosphonate MOFs based on a tetratopic linker

The tetratopic linker 1,1,2,2-tetrakis(4-phosphonophenyl)ethylene (H8TPPE) was used to synthesize the three new porous metal-organic frameworks of composition (M-2(H2O)(2) (H2TPPE)]center dot xH(2)O (M = Al3+, Ga3+, Fe3+, denoted as M-CAU-53 under hydrothermal reaction conditions, using the corresponding metal nitrates as starting materials. The crystal structures of the compounds were determined ab initio from powder X-ray diffraction data, revealing small structural differences. Proton conductivity measurements were carried out, indicating different conductivity mechanisms. The differences in proton conductivity could be linked to the individual structures. In addition, a thorough characterization via thermogravimetry, elemental analysis, IR-spectroscopy as well as N-2- and H2O-sorption is given.

Automated summary

The tetratopic linker H8TPPE was used to synthesize three new porous metal-organic frameworks under hydrothermal conditions. The crystal structures showed small differences and proton conductivity measurements revealed different mechanisms. Thorough characterization through various methods was conducted.