To accurately capture the interaction between molecular hydrogen and transition metal chelation complexes (framework-TMCl x ), a Morse potential (shown in Equation ) was fitted and used to parameterize the interaction. The fitting process involved considering various first-row elements (Co, Cu, Fe, Mn, and Ni) and late precious metals (Pd and Pt) using density functional theory (DFT). The first row TM were previously fit 11 using B3LYP-D3