Open questions include: (1) the direction and intensity of charge transfer and (2) the influence of the chemical environment of the open metal site on the adsorbent-adsorbate interaction. Recently, Cu L-edge near edge x-ray absorption fine structure (NEXAFS) measurements performed on Cu(I)-MFU-4l suggest the energies of the x-ray transitions correlate with the energy levels of the isolated small molecule adsorbates. The transition intensities were also found to be proportional to the binding energies of the guest molecules within Cu(I)-MFU-4l. To further understand the effects of guest binding on the structure, dynamics, and electron density distribution, we employ C and 1 H NMR spectroscopy measurements of ethylene adsorbed within two MOFs with different Cu(I) metal sites and conduct DFT and NLMO analyses to better understand the NMR spectra. These analyses are further informed by computational simulations for other ethylene-metal complexes.