Figure 4.

Distribution of stiffening/softening nonbonded contributions for (a) structures with BCT topology and IM, mIM, and dcIM ligands, and (b) structures with mIM ligand and BCT and AEI topologies. The vertical axes represent the sum of second derivative of van der Waals (vdW) energy () plotted with respect to the interatomic distances normalized with vdW radii (R̅_i,j = r_i,j/σ_i,j). The bulk moduli are 4.7, 9.4, and 7.1 for the BCT structures with IM, mIM, and dcIM ligands, and 6.3 and 7.0 for the AEI structures with IM and mIM ligands, respectively (values are in GPa). (c, d) Atomic representation and primary and secondary networks for the mIM ligand structures with BCT and AEI topologies, respectively. Details of ligands and metals were omitted in visualization of the primary and secondary networks for clarity. The primary net is demonstrated with red tubes and secondary net with cyan tubes; white, black, blue, and gray spheres represent H, C, N, and Zn atoms, respectively. The corresponding structures with IM ligand have the same primary net and no secondary net.