A research team from Hokkaido University has developed a novel method that could be used for recycling CO2 waste, while also producing molecules useful for drug development.
Why are scientists interested in recycling CO2?
In addition to the significant demand for carbon-neutrality, chemists are progressively interested in utilising Carbon Dioxide (CO2) in syntheses since it is abundant, inexpensive, relatively nontoxic, and renewable.
However, the reactivity of CO2 is relatively low. To overcome this, the team led by Professor Tsuyoshi Mita utilised an electrochemical method, where in which an electron is added to either the CO2 molecule or to the other molecule in the solution; this makes it far easier for them to react with each other.
This study is considered a breakthrough in the scientific community, as CO2 is used to carry out a traditionally difficult type of transformation with unprecedented efficiency. When certain conditions are met, electrons can be shared between many atoms in a molecule by what is called an ‘aromatic system.’
These systems are especially stable and difficult to break, but the new method developed at ICReDD is able to dearomatise (or break) these stable aromatic systems by adding CO2 to the molecule with the help of electricity. This process has potential applications in recycling CO2 and producing high value-added dicarboxylic acids from simple starting materials, which essentially solves two problems at once.
How was this reaction made possible?
Prior to the experiments, ICReDD scientists screened various heteroaromatic compounds by calculating their reduction potentials, which is a measure of how a compound will react when subjected to an electric environment.
The results enabled researchers to identify potentially reactive compounds and carry out targeted electrochemical experiments. This demonstrated that a wide variety of substrates that exhibit highly negative reduction potentials can very efficiently undergo this unprecedented dearomative addition of two CO2 molecules.
Therefore, the obtained dicarboxylic acids can be easily and cost-effectively modified into key intermediates for biologically active compounds, which could lead to more efficient and economical drug development.
Researchers involved in this study attributed the rapid development of this new process to their strategy of primarily performing computational analyses that informed their experimental choices in the lab.
“I started to learn computational chemistry when I joined ICReDD. Within one year, I was able to utilise advanced calculation techniques, which was very useful for guiding my decisions in the lab,” noted first author, Dr Yong You.
“It took only eight months to complete the research and publish the paper, which is much faster than a conventional project involving experiments. Significant research time is saved because a computer can reliably predict the feasibility of the reactant structures and possible reaction pathways” concluded Tsuyoshi Mita, leader of the project.
This study was conducted at the Institute for Chemical Reaction Design and Discovery (ICReDD) in Hokkaido University.
