Computational details. The DFT calculations were performed with the Quantum Espresso package (v 6.4) within the generalized gradient approximation (GGA) of Perdew, Burke and Ernzerhof (PBE) and long-range interactions described with the semiempirical approach proposed by Grimme (PBE+D2). We use the Rappe-Rabe-Kaxiras-Joannopoulos ultrasoft (rrkjus) pseudopotentials without semicore states in valence. The convergence threshold on forces is 0.0001 Ry/Bohr and the wavefunctions and charge density cutoffs are set to 100 and 1000 Ry, respectively. All the calculations are performed using the low-spin (S = 0) electronic configuration for the Fe(II) atoms. The Brioullin zone is sampled using a 3 × 3 × 3 Monkhorst-Pack k-point grid. The Becke-Johnson (BJ) damping scheme together with the D3 Grimme approach (PBE+D3+BJ) was also used to perform a Barder charge analysis in the loaded MOFs. The same pseudopotentials, force thresholds, Monkhorst-Pack k-point grid, wavefunctions and charge density cutoffs than for PBE+D2 were used for this functional.