Isotope-selective pore opening in a flexible metal-organic framework
Linda Bondorf, Jhonatan Luiz Fiorio, Volodymyr Bon, Linda Zhang, Mariia Maliuta, Sebastian Ehrling, Irena Senkovska, Jack D. Evans, Jan‐Ole Joswig, Stefan Kaskel, Thomas Heine, Michael Hirscher
Abstract
Flexible metal-organic frameworks that show reversible guest-induced phase transitions between closed and open pore phases have enormous potential for highly selective, energy-efficient gas separations. Here, we present the gate-opening process of DUT-8(Ni) that selectively responds to D 2 , whereas no response is observed for H 2 and HD. In situ neutron diffraction directly reveals this pressure-dependent phase transition. Low-temperature thermal desorption spectroscopy measurements indicate an outstanding D 2 -over-H 2 selectivity of 11.6 at 23.3 K, with high D 2 uptake. First-principles calculations coupled with statistical thermodynamics predict the isotope-selective gate opening, rationalized by pronounced nuclear quantum effects. Simulations suggest DUT-8(Ni) to remain closed in the presence of HT, while it also opens for DT and T 2 , demonstrating gate opening as a highly effective approach for isotopolog separation.