A group of chemists from Rice University has created a more cost-effective and ecologically friendly method of incorporating chlorine into chemical building blocks for pharmaceuticals, plastics, pesticides, and other necessary goods. The study was published in Nature Synthesis.
Led by Julian West, researchers developed a photocatalytic process that uses iron and sulfur catalysts activated by mild blue light to add chlorine atoms to organic molecules. Image Credit: Rice University
Chlorine is necessary for daily life, including food preservation and pool cleanliness.
The research team, led by Julian West, an Assistant Professor of Chemistry and a Cancer Prevention and Research Institute of Texas (CPRIT) Scholar, created a photocatalytic method that adds chlorine atoms to organic molecules using iron and sulfur catalysts activated by mild blue light.
The harsh chemicals and high temperatures needed for chlorination—which can produce challenging-to-purify byproducts—are no longer necessary.
Our method uses sustainable, low-cost catalysts and operates at room temperature with gentle blue light. It provides a targeted, efficient way to chlorinate molecules without conventional approaches’ environmental and purification challenges.
Julian West, Assistant Professor, Chemistry, Rice University
One key advantage of the team's method is its precise control over chlorine placement on molecules, a process known as anti-Markovnikov hydrochlorination. By carefully affixing chlorine atoms to less reactive regions of the initial molecules, this accuracy produces extremely pure products. Chemists can avoid additional purification procedures with this method, which are frequently expensive and time-consuming.
The scientists also revealed a new step in this procedure: adding the stable hydrogen isotope deuterium to heavy water. This step may increase the stability of some medications, extending their half-lives in the body and possibly improving their efficacy.
It’s exciting that this method could open new doors for modifying pharmaceuticals and natural products in ways that weren’t possible with older techniques.
Julian West, Assistant Professor, Chemistry, Rice University
Rice students Kang-Jie Bian, Shih-Chieh Kao, Ying Chen, Yen-Chu Lu, David Nemoto Jr., and Xiaowei Chen collaborated on this study.
Angel Martí, a professor and chair of chemistry as well as a professor of bioengineering, materials science, and nanoengineering, also contributed to this research. CPRIT, the Welch Foundation, the Research Corporation for Science Advancement, and the American Chemical Society Petroleum Research Fund supported the research.
Journal Reference:
Bian, K., et al. (2024) Anti-Markovnikov hydro- and deuterochlorination of unsaturated hydrocarbons using iron photocatalysis. Nature Synthesis. doi.org/10.1038/s44160-024-00698-z