Revolutionizing organometallic chemistry: the 21-electron metallocene “sandwich”

This discovery could open up new directions in medicine, catalysis and energy.

Organometallic compounds, molecules made up of metal atoms and organic molecules, are often used to speed up chemical reactions and have played an important role in advancing the field of chemistry.

Metallocenes

Metallocenes, a type of organometallic compound, are known for their versatility and their unique “sandwich” structure. Their discovery constituted a significant contribution to the field of organometallic chemistry and led to the awarding of the Nobel Prize in Chemistry in 1973 to the scientists who discovered and explained their sandwich structure.

The versatility of metallocenes is due to their ability to “sandwich” many different elements to form a variety of compounds. They can be used in a variety of applications, including the production of polymers, glucometers (used to measure the amount of glucose in the blood), perovskite solar cells and, as a catalyst, a substance that increases the speed of a chemical reaction without being consumed or consumed. modified by the reaction itself.

Examples of metallocene chemical compounds, their number of electrons and their applications. Credit: Takebayashi et al., 2023

Recent development at OIST

Dr. Satoshi Takebayashi, researcher in the science and technology group of the Okinawa Institute of Science and Technology (OIST), in collaboration with Dr. Hyung-Been Kang, scientist in the engineering section of OIST, and scientists from Germany, Russia and Japan. , successfully developed a new metallocene compound at OIST.

The chemical structure of metallocenes can accommodate a variety of electron counts, allowing the formation of complexes containing up to 20 electrons. However, the 18-electron structure is the most preferred because it is the most stable version.

“Having more than 18 electrons is known to be rare because if you deviate from 18, the chemical bonds of metallocenes begin to lengthen, break and change structure. However, we added two more electrons to a 19 electron metallocene and created a 21 electron metallocene. I think most people didn’t think this was possible, but our 21-electron metallocene is stable in solution and solid state and can be stored for a long time,” Dr. Takebayashi explained.

With this new metallocene, we can potentially create new materials that can be used for applications in medicine, catalysis and the energy sector, helping to solve important global problems and improving our quality of life.

Research challenges and collaboration

Since the sandwich structure of metallocenes can be easily changed, the most difficult part of the research was for the scientists to demonstrate that the nitrogen had successfully bonded to the cobalt without altering the sandwich structure. They had to rigorously prove that the metallocene was correctly bonded to all neighboring carbon atoms and that the nitrogen

” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>atom was attached to the cobalt atom. To do this, Dr. Takebayashi organized a strong team of researchers with different specialties and showed unambiguously that all the elements had come together well.

“This progress would not have been possible without the participation of my collaborators who have carried out substantial work”, added Dr Takebayashi. Dr. Satoshi Takebayashi, Jama Ariai, Dr. Urs Gellrich, Sergey Kartashov, Dr. Robert Fayzullin, Dr. Hyung-Been Kang, Dr. Takeshi Yamane, Dr. Kenji Sugisaki, and Professor Kazunobu Sato co-authored a paper published in the newspaper