Description
In this project, we want to study of the Metal-Organic Frameworks (MOFs) UiO-66 and UiO-66-NH2 for aldol condensation reactions. We chose to investigate the cinnamaldehyde condensation between benzaldehyde and propanal.
The catalytically active sites of such Zr-terephthalate UiO-66 materials were identified as accessible Zr sites that arise during the synthesis of these materials (Angewandte Chemie Int. Ed., 51(20), 4887-4890, 2012). On these active sites, we have already computed a catalytic cycle for the aldol condensation reactions on both periodic and cluster models of the UiO-66. An extension of this research to the amino-functionalized counterpart is warranted, as this material was found to be more active and selective (Chem. Commun., 47, 1521-1523, 2011). This will enable us to unravel the role of the amino group during the catalytic cycle.
To achieve a good comparison between the UiO-66 and the amino-UiO-66 for their selectivity and activity, we need accurate hybrid functional calculations using the periodic code VASP. Why? First, this brings the results of periodic models on a comparable level of theory with the cluster models. Second, as the environment is better accounted for in periodic simulations, it makes it possible to estimate the effect of extra stabilization on the activation barriers compared to cluster calculations. These two issues are of particular importance, since accurate reaction barrier prediction is necessary if we want to compare experimental and theoretical results.
