GIST Develops Catalyst That Controls Chemical Reactions with Light

GIST (from left) Seongwook Park, integrated master's and doctoral course student (first author), and Professor Seokwon Hong. Photo by Gwangju Institute of Science and Technology

[Asia Economy Honam Reporting Headquarters Reporter Cho Hyung-joo] The research team led by Professor Hong Seok-won of the Department of Chemistry at GIST (Gwangju Institute of Science and Technology, President Kim Ki-seon) announced on the 16th that they have developed a ruthenium olefin metathesis catalyst whose reactivity can be controlled in real-time using light.

Olefin metathesis catalyst reactions have been widely applied in the synthesis of organic compounds with biological activity, such as polymers, fuel additives, and pharmaceuticals, by enabling the formation of new bonds or the introduction of various functional groups into organic compounds. Recently, the development of catalysts capable of switching metathesis reactions through external stimuli has been underway.

Existing on-off switching catalysts showed minimal reactivity control by external stimuli or used inconvenient stimuli such as acid-base or redox reactions.

The switching catalyst developed by the research team is the first case where the reaction stops upon exposure to light, contrary to previous catalysts, all of which initiated the metathesis reaction when exposed to light.

Furthermore, by focusing on the azobenzene functional group that changes its structure upon light exposure, the team introduced this structure into existing metathesis catalysts, thereby obtaining a catalyst whose structure changes according to light.

The developed catalyst exhibited a dramatic difference in reactivity depending on light exposure (60 to 300 times) in various metathesis reactions, which is significantly greater than the reactivity difference (1.5 to 2.5 times) of existing catalysts using the same strategy. Additionally, the newly developed catalyst demonstrated that by changing the light irradiation conditions during the reaction, the reactivity could be repeatedly switched on and off accordingly.

Professor Hong Seok-won stated, "This research achievement is significant as it is the first catalyst case that can stop the reaction using light," adding, "It is expected that the developed on-off switching catalyst will be applied to light-based patterning technologies such as photolithography."

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