Seoul National University team develops high-performance catalyst using four sulfur atoms — no rare metals needed

Researchers have opened a new path to high-performance catalysts using sulfur — an element abundant in nature — instead of costly, scarce rare metals. By engineering four sulfur atoms to work in concert, the team achieved reactivity that surpasses the limits of conventional main-group element catalysts, raising hopes of cutting the time and cost of developing new drug candidates.

The National Research Foundation of Korea announced that a research team led by Hong Seung-yun, a professor in the Department of Chemistry at Seoul National University, has developed a "polyatomic main-group element catalyst" designed so that multiple main-group elements cooperate as a single catalytic center.

Catalysts are substances that drive chemical reactions quickly and selectively in small quantities. They are an indispensable technology for producing high-value materials such as pharmaceuticals, agrochemicals and advanced materials.

High-performance catalysts today rely heavily on transition metals such as palladium. These metals are expensive due to limited reserves, their supply chains are unstable, and some carry toxicity concerns.

Main-group elements — carbon, nitrogen, oxygen and sulfur — which are plentiful in nature, have drawn attention as potential replacements. The challenge is that they struggle to exchange electrons flexibly and are difficult to tune freely.

The research team solved these limitations through "atomic cooperation." Rather than relying on the properties of a single atom, as conventional catalyst designs do, they engineered multiple atoms to react by combining their strengths.

Specifically, the team placed a single carbon atom at the center and arranged four sulfur atoms around it in a three-dimensional configuration. Even without direct bonds between the sulfur atoms, the design allows them to influence one another through space, moving as if they were a single team.

When the team applied the catalyst to halogenation reactions — attaching chlorine, bromine or iodine to molecules — it demonstrated the highest reactivity and broadest substrate applicability among existing methods.

Particularly notable was its effectiveness on pharmaceutical- and agrochemical-like molecules that had been difficult to react using conventional methods. Rather than resynthesizing a nearly complete, complex molecule from scratch, researchers can modify it into the desired form at the final stage.

In drug development, researchers make small modifications to a core molecular structure to generate large numbers of candidates and compare their efficacy. If this catalyst is put to practical use, it could reduce the burden of synthesizing each candidate from scratch and accelerate the pace of drug discovery.

The team also elucidated the mechanism behind the four sulfur atoms' cooperation. When one sulfur atom transfers a halogen to a molecule, the other sulfur atoms exert influence through space, weakening the bond between sulfur and the halogen. The collective involvement of multiple atoms in the reaction process boosts catalytic performance.

The research is also significant in that it expands the basic unit of catalyst design from a single atom to the cooperative action of multiple atoms. Combining various main-group elements beyond sulfur could open the door to an entirely new family of catalysts.

"When atoms are arranged well in space, properties and reactivity that are difficult to achieve with a single atom can be unlocked," Hong said. "We plan to expand the research to other main-group elements and a wider range of chemical reactions, while improving stability and scalability for use in actual industrial settings."

The findings were published in Nature Catalysis, an international journal in the field of catalysis.