Fig. 4: The relationship between linker pKa and MOF d-orbital energy.
From: Ligand field tuning of d-orbital energies in metal-organic framework clusters
The relationship between free-linker pKa and d-orbital extracted from the DFT computation of the bulk functionalized MOF. The d-energies are linearly related to the linker pKa with strong positive correlation. Dichloro functionality in the C2,3 position is highlighted in green. In blue, biphenyl† is substituted for the aromatic portion of bdc (i.e., biphenyldicarboxylate) and this MOF is also known as UiO-67. In red, pyrene§ is substituted for the aromatic portion of bdc (i.e., pyrenedicarboxylate) and this MOF is also known as IRMOF-1436. The gradients are 0.49 (UiO-66), 0.38 (MOF-5), 0.16 (MIL-125), and 0.13 (ZIF-8) eV/pKa. Bands that show up in the conduction band (d0 MOFs) are labeled with a blue background, while those that appear within the valence band (d10 MOFs) are labeled with a yellow background.
