In an effort to discover new 2D materials, a group of scientists from Ames National Laboratory determined the structure of boron monoxide. This compound was first discovered in the 1940s and has continued to interest research throughout the years. Scientists, however, were unable to determine the structure of the material due to technological limitations at the time. Using new NMR techniques and previously unavailable analytical tools, the team from Ames Lab has finally solved the structure of this deceptively simple material.
“At first we did not look to study this particular material,” said Frédéric Perras, a scientist from Ames Lab and member of the research team. “We’re actually trying to create a carbon-free covalent organic framework.” A covalent organic framework is a low density and porous material with a regularly ordered crystal structure. It is made up of organic molecules joined together by covalent bonds.
“However, after many synthesis attempts, we could not obtain a highly crystalline covalent organic framework material,” said Wenyu Huang, another scientist from Ames Lab and a member of the team. Perras and Huang’s groups are interested in these materials for alternative energy use.
The team ended up creating a boron-based material that Perras said was difficult to describe. Through their research, they reached literature dating back to the 1940s with descriptions of the exact reaction the team performed, and the synthesis of a material called boron monoxide. Unfortunately, previous scientists were unable to determine the structure of the material. This research is further discussed in the paper published in Journal of the American Chemical Society.
Fortunately, the technology for materials research has advanced since the 1940s. “Because of our expertise in nuclear magnetic resonance spectroscopy, and the development of new methods to which people in the 40s, 50s, and 60s did not have access, we think we can put this almost century-old mystery to rest. ,” said Perras.
Perras explained that boron monoxide is made using precursor molecules that act like building blocks. These molecules stick together through dehydration reactions. The key to understating structure is knowing how the blocks are physically arranged. “So we developed some NMR methods that allowed us to study the orientation of these building blocks in relation to each other. Basically, we found that adjacent precursor molecules are organized parallel to each other, which is matched by one of the previously proposed models,” Perras said.
“We also applied several other techniques, including powder X-ray diffraction, which showed that these nanosheets organize themselves in what is called a turbostratic arrangement,” says Perras. He explained that these stacked nanosheets are like a stack of paper thrown on a table. When they landed, they didn’t fit perfectly, but they stayed in a stack.
According to Perras, there is a lot of recent interest in synthesizing new boron-based 2D materials. Understanding its structure may lead to the synthesis of other useful boron-based 2D materials. “What really excites me is the fact that this is an old problem. It’s a basic material; if you write down the chemical formula, it’s BO. So, it’s interesting from the point of view that we finally solved the structure this,” said Perras
Frédéric A. Perras et al, The Structure of Boron Monoxide, Journal of the American Chemical Society (2023). DOI: 10.1021/jacs.3c02070
Provided by Ames National Laboratory
Citation: Structure of elusive boron monoxide finally determined after 83 years (2023, July 18) retrieved on July 18, 2023 from https://phys.org/news/2023-07-elusive-boron-monoxide -years.html
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