Tracking the evolution and differences between guest-induced phases of Ga-MIL-53 via ultra-wideline 69/71Ga solid-state NMR spectroscopy.

摘要: Abstract Ga-MIL-53 is a metal-organic framework (MOF) that exhibits “breathing effect,” in which the pore size and overall MOF topology can be influenced by temperature, pressure, host-guest interactions. The phase control afforded this flexible renders promising material for guest storage sensing applications. In work, structure behavior of four phases ( as , ht enp lt ), along with CO 2 adsorbed within at various loading levels, has been investigated using 69/71 Ga solid-state NMR (SSNMR) experiments 21.1 T 9.4 T. SSNMR spectra are observed to very sensitive distortions octahedral GaO 6 secondary building units Ga-MIL-53; extension, parameters indicative particular crystallographic Ga-MIL-53. evolution levels reveals specific level offers profound degree over phase, data also suggests re-entrant transition present. Adsorption organic compounds combination thermal gravimetric analysis (TGA), powder X-ray diffraction (pXRD) experiments. Notably, pXRD reveal adsorption interactions trigger unambiguous changes long-range Ga-MIL-53, while yield valuable information regarding effect adsorbates on local environments. This approach shows promise ultra-wideline investigation other quadrupolar metal nuclei MIL-53 e.g. In-MIL-53) MOFs general, particularly regards adsorption-related