Hydrogen is considered a promising energy source for the future, provided it is produced in an environmentally friendly manner. It also plays a significant role in the production of essential substances and active ingredients. However, splitting water molecules (H2O) into hydrogen gas (H2) and oxygen presents a significant challenge due to the stability of water. To overcome this hurdle, chemists rely on catalysts to activate water and facilitate its reaction.
A team of researchers led by Prof. Armido Studer at the Institute of Organic Chemistry at Münster University in Germany has developed an innovative photocatalytic process for water activation. Unlike most other methods that employ transition metal complexes, the team’s approach utilizes triaryl phosphines. Their findings, recently published in Nature, mark a significant advancement in radical chemistry, a highly active research field. Radicals, which are typically highly reactive intermediates, are employed in this process.
The team employs a unique intermediate called a phosphine-water radical cation as the activated water, enabling the easy detachment of hydrogen atoms from H2O and their transfer to another substance. This reaction is driven by light energy.
According to Prof. Studer, “Our system provides an excellent platform for investigating unexplored chemical processes that utilize hydrogen atoms as reagents in synthesis.”
Dr. Christian Mück-Lichtenfeld, who analyzed the activated water complexes using theoretical methods, explains, “The hydrogen-oxygen bond in this intermediate is remarkably weak, enabling the transfer of a hydrogen atom to various compounds.”
Dr. Jingjing Zhang, responsible for the experimental work, adds, “The activated water’s hydrogen atoms can be transferred to alkenes and arenes in mild conditions, known as hydrogenation reactions.”
Hydrogenation reactions hold tremendous significance in pharmaceutical research, the agrochemical industry, and materials sciences.
Source: University of Münster