Using the means of quantum chemistry, scientists from the Max Plank Institute for Chemical Energy Conversion discovered new properties of the oxygen evolving complex (OEC). It is known that OEC is the catalyst that splits water molecules to build carbohydrates using sunlight. The researchers were now able to establish and solve its enigmatic spectroscopic behavior.
Dr. Dimitrios Pantazis, scientist at the MPI CEC, and his team recognized two different types of spectroscopic signals, which could be converted to each other using different treatments without changing their structure. The researchers identified that the cause of the signals are two electrically similar structures of the complex.
A partial cubic structure made of manganese, calcium and oxygen (Mn4CaO5) makes up the core of the enzyme. Panatazis comments that although the difference is only in one bond, this has a big impact on the electronic structure and spectroscopic properties of the molecule. The energy of the structures is almost identical allowing easy bond swapping.
One of the core findings of the team is the distinct spectroscopic signature of each structure. With this research, the time is certain that they are now able to better understand the process of water oxidation, which is key to developing energy research further.
Pantazis’s team is now working on identification of the origin of the oxygen atoms released from the enzyme as a molecular oxygen. If they prove that these oxygen atoms are the same as these involved in the bond swapping process, the scientists are convinced they will gain further understanding of the mechanism of water oxidation at atomic level.