HKU Chemists Develop Chameleon-Like Molecular Chain with Dual Ion Binding Capability

In a groundbreaking discovery, a team of researchers from the University of Hong Kong (HKU) has successfully created a molecular chain that can adapt to its environment by changing its shape to bind with either copper(I) or sulfate ions. This innovative breakthrough has significant implications for various fields, including environmental monitoring, medical diagnostics, and even the extraction and recycling of essential ions.

The team, led by Professor Ho Yu Au-Yeung, has developed a catenane, a type of molecule composed of interlocked rings, which can rotate freely to adjust its binding sites and accommodate ions with opposite charges. This unique property allows the catenane to bind strongly and selectively to either copper(I) cations or sulfate anions, making it an efficient candidate for molecular switches and machines.

The challenge in designing a host that can bind to both cations and anions was overcome by installing both binding sites on each ring, allowing the catenane to adjust its position and adapt to the specific ion it encounters. This chameleon-like behavior enables the catenane to recognize and bind to ions with different geometries and charges, much like a chameleon changing its appearance to fit in its surroundings.

The significance of this discovery extends beyond its industrial and environmental applications. Copper(I) and sulfate ions are essential for proper cell growth and organism development, and the strong and selective binding of these ions by the catenane host could be exploited for the extraction and recycling of these ions from environmental samples. Additionally, new technologies for selective recognition and binding of ions and minerals will be useful for diagnostic and therapeutic purposes.

“This work highlights catenane as an efficient candidate for potent molecular receptors with versatile structures, switchable properties, and guest binding behaviors,” said Professor Au-Yeung. The team is now working on developing more sophisticated catenane hosts for the simultaneous binding of multiple cations, anions, and ion pairs.

The research paper, titled “Dynamic mechanostereochemical switching of a co-conformationally flexible [2]catenane controlled by specific ionic guests,” was published in Nature Communications and can be accessed online. The team’s work was supported by the CAS-Croucher Funding Scheme for Joint Laboratories, the Collaborative Research Fund, and the General Research Fund from the Research Grants Council of Hong Kong.

Professor Au-Yeung, an Associate Professor in the Department of Chemistry at HKU, has received several prestigious awards for his research, including the Croucher Innovation Award, the Graeme Hanson Early Career Researcher Award, and the HKU Outstanding Young Researcher Award. His research group focuses on the chemistry of mechanically interlocked molecules and their applications in coordination chemistry, host-guest recognition, catalysis, and materials.

This innovative breakthrough has the potential to revolutionize various fields and could lead to the development of new technologies for environmental monitoring, medical diagnostics, and more.

Historical Context:

The concept of molecular recognition and binding has been a topic of interest in chemistry for decades. The development of molecular machines and switches has been a significant area of research in recent years, with scientists working to create molecules that can change shape or bind to specific molecules in response to environmental stimuli. The discovery of catenanes, a type of molecule composed of interlocked rings, has been a major breakthrough in this field. Catenanes have been shown to have unique properties, such as the ability to rotate freely and adjust their binding sites, making them ideal candidates for molecular switches and machines.

In the 1990s, researchers began to explore the use of catenanes as molecular machines, and since then, there have been numerous studies on their properties and applications. However, the development of a catenane that can bind to both cations and anions has been a significant challenge. The recent breakthrough by the HKU team marks a major milestone in this field, as it demonstrates the ability of a catenane to adapt to its environment and bind to ions with opposite charges.

Summary in Bullet Points:

• A team of researchers from the University of Hong Kong (HKU) has developed a molecular chain that can adapt to its environment by changing its shape to bind with either copper(I) or sulfate ions. • The catenane, a type of molecule composed of interlocked rings, can rotate freely to adjust its binding sites and accommodate ions with opposite charges. • The unique property of the catenane allows it to bind strongly and selectively to either copper(I) cations or sulfate anions, making it an efficient candidate for molecular switches and machines. • The discovery has significant implications for various fields, including environmental monitoring, medical diagnostics, and the extraction and recycling of essential ions. • The catenane can recognize and bind to ions with different geometries and charges, much like a chameleon changing its appearance to fit in its surroundings. • The research has the potential to revolutionize various fields and could lead to the development of new technologies for environmental monitoring, medical diagnostics, and more. • The team is now working on developing more sophisticated catenane hosts for the simultaneous binding of multiple cations, anions, and ion pairs. • The research paper was published in Nature Communications and was supported by several funding schemes, including the CAS-Croucher Funding Scheme for Joint Laboratories and the Research Grants Council of Hong Kong.