We now discuss limitations of our study. First, in the construction of our Ni(PyC-X) 2 library, we assumed de novo synthesis of a new Ni(PyC-X) 2 MOF would result in a two-fold interpenetrated diamondoid network with a cis Ni coordination environment, as in the parent Ni(PyC) 2 MOF. This assumption turned out to be valid for Ni(PyC-m-NH 2 ) 2 . We also assumed the unit cell of the Ni(PyC-X) 2 MOF would be identical to the Ni(PyC) 2 MOF. For Ni(PyC-m-NH 2 ) 2 , Tab. shows that the unit cell was altered by the addition of the NH 2 group. To see the difference in predicted adsorption, Fig. shows the simulated adsorption in Ni(PyC-m-NH 2 ) 2 using the (i) experimentally determined structure and (ii) predicted structure. Still, our virtual screening correctly predicted that functionalizing the parent Ni(PyC) 2 structure with an amino group would enhance its Xe/Kr selectivity. Second, our molecular models and simulations of noble gas adsorption in the MOFs assumed that each MOF was rigid, neglecting e.g. the rotation of the PyC-X ligands and fluctuations in the pore size, which could affect adsorption . Still, the simulations predicted noble gas adsorption in Ni(PyC) 2 and Ni(PyC-m-NH 2 ) 2 quite well (see Figs and) without modification of the off-the-shelf force field (UFF). Also, our virtual screening of the Ni(PyC-X) 2 library for noble gas separations (i) pertained to dilute con- Xe/Kr pressure increases from P " . bar to . bar.