KAUST-7 (NbOFFIVE-1-Ni) Metal Organic Frameworks (MOFs) Powder for Gas Absorption and Separation, CGASMOFKAUST7

KAUST-7 (also designated as NbOFFIVE-1-Ni, with chemical formula Ni(pyrazine)2(NbOF5)]n) is a benchmark pillared-layer hybrid ultramicroporous material (HUM) belonging to the pcu (primitive cubic) topology family. Developed at King Abdullah University of Science and Technology (KAUST), it is constructed from 2D [Ni(pyrazine)2]^{2+} square grids pillared along the c-axis by trans-directing inorganic oxofluoroniobate [NbOF5]^{2-} octahedra.

The key structural features and functions of the KAUST-7 are: (1) Periodic Fluorinated Ultramicropores: Pore Aperture: ~ 3.0–3.1 Å (narrowest window), tailored precisely between the kinetic diameters of propylene (4.0 Å nominal / 3.8 Å cross-section) and propane (4.3 Å). Channel Dimensions: 1D square channels with a diagonal cage dimension of ~ 4.75 Å. (2) Electrostatic Pore-Surface Chemistry: The inorganic [NbOF5]^{2-} pillars project four equatorial fluoride atoms directly into the center of each channel, generating a periodic, highly dense electrostatic field that strongly polarizes and confines unsaturated hydrocarbons without requiring open metal sites. (3) Hydrolytic & Thermal Stability: The (NbOF5)^{2-} pillar forms strong coordination bonds with Ni2+, providing moisture resilience against humidity and boiling water, and remaining thermally stable up to ~ 250–280°C.

References:

1. M. R. Tchalala, et al., Fluorinated MOF platform for selective removal and sensing of SO2 from flue gas and air, Nature Communications, 2019, 10, 1328
2. J. Lv, et al., Inorganic Pillar Center-Facilitated Counterdiffusion Synthesis for Highly H2 Perm-Selective KAUST‑7 Membranes, ACS Appl. Mater. Interfaces (2018) 10 (34): 28656–28663.