LEDs are commonly used in the electronic screens of our TVs, smartphones and other devices; now, researchers at the Institute of Chemical Reaction Design and Discovery (ICReDD) at Hokkaido University have used blue LEDs to develop a more sustainable way to manufacture key chemical subunits that have potential uses in pharmaceutical and photoelectronic development.
Researchers used blue LEDs in combination with a copper-based molecular catalyst to perform what is known as a cross-coupling reaction in which two molecules are connected via a carbon-carbon bond. This is one of the most common types of reactions and is essential in creating most of the chemical products used today. The use of copper - a cheaper and more commonly available metal - as a catalyst for a cross-coupling reaction is a major breakthrough in sustainability, as this reaction is typically dependent on the use of precious metals such as palladium.
The new method is also advantageous because the copper metal in the molecular catalyst itself absorbs the blue light, instead of needing a separate light-absorbing compound in addition to the catalyst. This not only makes the synthesis cheaper and easier to perform, but also easier to control as there are fewer moving parts.
The blue light plays a key role in the activation of the copper-based catalyst. Theoretical calculations showed that this light exposure causes electrons to move from the metal copper atom to a connected subunit of the molecular catalyst. This excited state has separated electrical charges, making the catalyst much more reactive, and researchers were able to use it to perform a cross-coupling reaction that creates an acyl group useful for the synthesis of drugs and photoelectronic materials.
A key aspect of this method is that the formation of the acyl group occurs asymmetrically. This means that one of the two possible mirror image versions of the product molecule is selectively produced, a function that is highly desired for the development of new drugs. Researchers tested their new method with several different starting materials, including a material derived from probenecid, a drug for arthritis. The product obtained from this starting material has potential uses in the pharmaceutical industry. The high selectivity of this method and its compatibility with compounds used in medicine highlights its potential applicability.
Implementation of this new method is expected to both provide cost savings and increase the sustainability of the production of a wide range of chemical compounds with potential applications in medicine and electronics. Its utilization of widely available materials makes it particularly appealing.
"This synthetic method is a breakthrough because it combines two easily accessible objects, blue LED light and copper, to achieve a coupling reaction that did not exist before," commented Assistant Professor Yusuke Masuda. "Technology that produces useful compounds from resources that are abundantly available on Earth is crucial to the sustainable development of mankind. I expect this progress will be a milestone in the development of sustainable molecular synthetic methods."
Citation: Blue LEDs light the way to sustainable development (2022, 18 January) retrieved 19 January 2022 from https://phys.org/news/2022-01-blue-sustainable.html
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