General Chemistry Seminar

In the present seminar I will present ab initio molecular dynamics calculations based on DFT+U carried out on the natural complex PSII, on a cobalt-based inorganic system (CoCat) and on a manganese-based inorganic system (MnCat). Using a Quantum Mechanics / Molecular Mechanics framework based on the recently reported X-ray structure  we have explored the free energy landscape associated with the transition between distinct geometrical structures of the Mn4CaO5 catalytic centre along the pathway between S2 and S3 states. These calculations also shed some light on the mechanism of Mn cluster oxidation by TyrZ and on the binding of substrate water.

On the side of inorganic water splitting, we investigate cluster models of a cobalt-based catalyst (CoCat) in explicit water solution, providing insights into the pathways for oxygen evolution and identifying the formation of Co(IV)-oxyl species as the driving ingredient for the activation of the catalytic mechanism. The comparison between calculations and X-ray adsorption data on CoCat and active and inactive Mn-based catalysts revealed the details of the structural motifs of the catalytic sites. The achieved results suggest differences and similarities between the bio-inspired inorganic catalysts and the catalytic core of PSII.