Looking for the perfect molecule

Visiting Humboldt scientist: Dr. Peng Zhang

Developing and then synthesizing new types of molecules on the nanoscale is the research project of chemist Dr. Peng Zhang from China. The Humboldt fellow working at the Institute for Physical Chemistry (IPC) at the University of Stuttgart aims to modify the properties of molecules in order to improve their functions.

The idea is to make individual molecules act as magnets. If this is successful, such molecules could be used for magnetic data storage in the future. One of the major challenges is the fact that air and water disturb the production process of molecules and must therefore be excluded. This is why Zhang conducts the synthesis in a so-called glovebox, a method with which he has gathered experience in his home country.

Joris van Slageren is professor for modern spectroscopic methods and molecular nano-magnetism at IPC and has known Zhang’s doctoral supervisor for many years. After receiving an application from Zhang, he spoke with him and with his future supervisor. The post-grad’s scientific career and his research plan convinced van Slageren, and he offered Zhang a one-year position in his institute. Because Zhang’s project has enormous potential, the Humboldt Foundation also agreed to lend support.  

Patience and endurance
His Chinese doctoral supervisor had done his doctorate in Germany and worked there for seven years. This is why Peng Zhang of the Changchun Institute of Applied Chemistry (CIAC) also wanted to move his research to Germany, at least temporarily. “The field of science I am working on is much more advanced here,” explains the chemist, whose Humboldt fellowship runs from 1 January 2017 to the end of December 2018.

“I sent a lot of e-mails to Germany back then. Finding a post-doc position was almost as difficult as finding an apartment for my wife and me in Stuttgart,” the Chinese researcher reports with a smile. But in both cases, he was successful in the end. The experience showed once again how an internationally active scientific network can bring people together so their cooperation can accelerate scientific progress.

Der Chemiker Dr. Peng Zhang aus China führt die Synthese der neuartigen Moleküle in der Glovebox durch.
Chemist Dr. Peng Zhang from China synthesizes new molecules in the glovebox.

Molecules as highly effective data storage
Van Slageren and his group of researchers are examining molecular magnetic materials. They are spurred by the idea that in principle it must be possible to store a data bit in a molecule. A trailblazing concept, because molecules are much, much smaller than the magnetic particles that are used in hard drives today. “This would lead to significantly higher data density on hard drives,” Zhang’s guest professor explains, mentioning an impressive factor of 100 to 1,000.

The institute specializes in the physical measurement of the properties of molecules. The scientists there are conducting fundamental research to help them understand why certain molecules show stable magnetization and others do not.  

Scientific give and take
In his work, Zhang benefits from the physical measurement methods used at the institute in Stuttgart. “I have to learn some of the magnetic measurement processes like electron spin resonance (EPR) and magnetic circular dichroism (MCD),” he says, adding: “In China we do not have these devices for measurement methods that would let us better understand the electronic structure and magnetic properties.” In turn, the chemist contributes his expertise on synthesizing new molecules. “The new molecule we want unfortunately does not yet exist. I have to synthesize it first,” he explains his mission. The search for the perfect molecule is truly a never-ending task. Together with the other members of the work group, Zhang examines the properties of each newly produced molecule. The results of these physical measurements let him design and synthesize an even better molecule in the next step.

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