Innovation in Decoding Complex Molecular Structures
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Molecular structures are usually determined using X-ray diffraction on single crystals. This method makes it possible to establish the three-dimensional structure of complex substances in the crystal lattice and derive a wide range of information, such as the arrangement of the atoms and the expected chemical reactivity of the compound. X-ray diffraction is therefore the standard method of characterizing unknown substances. The challenge here is that the crystals of the substances under examination must be of a suitable size. This is why researchers often fail to determine a substance’s structure.
New method reduces sample size requirements
With electron crystallography, on the other hand, electrons are diffracted on the crystal instead of X-ray photons. “What makes this method special is that we can use tiny, crystalline particles with sizes in the range of 100-1000 nanometers,” says Dr. Julian Holstein, who is the correspondent author of the article alongside Dr. Tim Grüne from the University of Vienna. As a result, powdery, crystalline deposits, which can often even be found in raw products that are still contaminated, become accessible as samples. These particles cannot be seen with the naked eye or even with extremely powerful optical microscopes. “Even samples that are unsuitable for high-brilliance synchrotron radiation due to their small crystal size can be examined using electron diffraction. Due to less stringent demands on sample size, we are also able to shorten the very time-consuming crystallization processes in the laboratory,” adds Dr. Julian Holstein. As a result, this method also has a lot of interesting potential for other scientific areas such as materials science or pharmacy.
Hydrogen atoms can be recognized more easily
Electron diffraction also offers yet another advantage. Using this method, very light hydrogen atoms, which often play a key role in both chemical reactions and biological processes, can be detected particularly effectively. What’s more, the oxidation state of certain elements in the crystal can be experimentally determined, which was previously not possible. This opens up new research opportunities in the field of catalyst research, hydrogen storage and drug development.
Prof. Guido Clever, Professor of Bioinorganic Chemistry at TU Dortmund University and one of the authors of the project says: “We are enthusiastic about the results of the measurements we carried out on our samples at ETH Zurich and the University of Vienna. We are confident that this method can lead to a series of previously inaccessible results in the areas of functional molecules and materials, solvation science and drug research.”
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