CFA-14 – a perfluorinated metal–organic framework with linear 1-D CoII-chains showing temperature dependent spin-chain magnetic ordering

Abstract

The synthesis and crystal structure of the perfluorinated metal–organic framework (MOF) CFA-14 (Coordination Framework Augsburg University-14), Co^II₂(tfpb)(OH)₂ (H₂-tfpb = 1,4-bis(3,5-bis(trifluoromethyl)-1H-pyrazole-4-yl)benzene) are described. The cobalt-containing MOF crystallizes in the tetragonal crystal system within the space group I4₁/acd (no. 142) and the unit cell parameters are as follows: a = 20.3213(11) Å, c = 12.4045(8) Å, V = 5122.5(6) ų. CFA-14 features a porous two-fold interpenetrated 3-D microporous structure constructed from 1-D chains of cobalt(II) ions expanding in the c-direction, bridged by OH⁻ groups and tfpb²⁻ ligands. The structure exhibits quadratic channels running along the c-axis. CFA-14 is fully characterized by synchrotron single crystal X-ray diffraction, thermogravimetric analysis, variable temperature powder X-ray diffraction, IR- and UV-Vis spectroscopy, photoluminescence and gas sorption measurements. Moreover, the magnetic properties of CFA-14 are examined via SQUID measurements.