Free Energy of Ligand Removal in the Metal-Organic Framework UiO-66.
We report an investigation of the "missing-linker phenomenon" in the Zr-based metal-organic framework UiO-66 using atomistic force field and quantum chemical methods. For a vacant benzene dicarboxylate ligand, the lowest energy charge-capping mechanism involves acetic acid or Cl-/H2O. The calculated defect free energy of formation is remarkably low, consistent with the high defect concentrations reported experimentally. A dynamic structural instability is identified for certain higher defect concentrations. In addition to the changes in material properties upon defect formation, we assess the formation of molecular aggregates, which provide an additional driving force for ligand loss. These results are expected to be of relevance to a wide range of metal-organic frameworks.
Centre for Sustainable Chemical Technologies and Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, United Kingdom.
Jessica K
JK
Bristow
Centre for Sustainable Chemical Technologies and Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, United Kingdom.
Katrine L
KL
Svane
Centre for Sustainable Chemical Technologies and Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, United Kingdom.
Davide
D
Tiana
Centre for Sustainable Chemical Technologies and Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, United Kingdom.
Jonathan M
JM
Skelton
Nanochemistry Research Institute/Curtin Institute for Computation, Department of Chemistry, Curtin University , P.O. Box U1987, Perth, Washington 6845, Australia.
Julian D
JD
Gale
Centre for Sustainable Chemical Technologies and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom; Global E Institute and Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Korea.
Aron
A
Walsh