Adsorption of Olefins at Cupric Ions in Metal-Organic Framework HKUST-1 Explored by Hyperfine Spectroscopy.

Metal-organic frameworks (MOFs) represent a promising platform for gas storage and separation. In this work, adsorption of olefins in Zn-doped HKUST-1 metal-organic framework is explored with hyperfine spectroscopy. By means of electron-nuclear double resonance and hyperfine sublevel correlation spectroscopy, we detect the interaction between the electron spins of the Cu sites of the MOF and the H nuclear spins of adsorbed CH and CH. Further analysis of the measured spectra allows us to precisely locate the protons in the vicinity of the Cu ions and thereby establish ensemble-averaged structural models of the olefin molecules adsorbed at the open metal sites of HKUST-1.