Unraveling the Molecular Details of the “Gate Opening” Phenomenon in ZIF-8 with X-ray Absorption Spectroscopy

The local structural changes associated with the ZIF-8 framework flexibility upon nitrogen gas adsorption have been studied by in situ X-ray absorption spectroscopy (XAS) and high-energy-resolution fluorescence-detected near-edge structure (HERFD-XANES) spectroscopy. Different thermodynamic conditions (isobar isotherm) used to explore so-called “gate opening” transition which hexagonal pore windows of sodalite cage open, increasing accessible volume for adsorption. To elucidate source spectral XANES region spectra observed along through from closed open configuration, ab initio calculations performed. Our results demonstrate that configurations involves not only rotation MeIM ligand but also a further bend Me group away plane defined IM ring. Additionally, contribution N2 molecules adsorbed center 4-ring window has included scattering model fully reproduce main features configuration.