Using advanced microscopy techniques at , researchers have recorded the breaking of a single chemical bond between a carbon and an iron atom on different molecules.
The team used a high-resolution atomic force microscope (AFM) operating in a controlled environment at Princeton’s Imaging and Analysis Center. The AFM probe, whose tip ends in a single copper atom, was moved gradually closer to the iron-carbon bond until it was ruptured. The researchers measured the mechanical forces applied at the moment of breakage, which was visible in an image captured by the microscope. A team from Princeton University, the University of Texas-Austin and ExxonMobil reported the results in a paper published on September 24, 2021, in Nature Communications.
“It’s an incredible image — being able to actually see a single small molecule on a surface with another one bonded to it is amazing,” said coauthor Craig Arnold, the Susan Dod Brown Professor of Mechanical and Aerospace Engineering and director of the Princeton Institute for the Science and Technology of Materials (PRISM).
“The fact that we could characterize that particular bond, both by pulling on it and pushing on it, allows us to understand a lot more about the nature of these kinds of bonds — their strength, how they interact — and this has all sorts of implications, particularly for catalysis, where you have a molecule on a surface and then something interacts with it and causes it to break apart,” said Arnold.
Nan Yao, a principal investigator of the study and the director of Princeton’s Imaging and Analysis Center, noted that the experiments also revealed insights into how bond breaking affects a catalyst’s interactions with the surface on which it’s adsorbed. Improving the design of chemical catalysts has relevance for biochemistry, materials science and energy technologies, added Yao, who is also a professor of the practice and senior research scholar in PRISM.
In the experiments, the carbon atom was part of a carbon monoxide molecule and the iron atom was from iron phthalocyanine, a common pigment and chemical catalyst. Iron phthalocyanine is structured like a symmetrical cross, with a single iron atom at the center of a complex of nitrogen- and carbon-based connected rings. The iron atom interacts with the carbon of carbon monoxide, and the iron and carbon share a pair of electrons in a type of covalent bond known as a dative bond.
Yao and his colleagues used the atomic-scale probe tip of the AFM… Brinkwire News Summary.