Hexbyte Glen Cove An updated understanding of how to synthesize value-added chemicals thumbnail

Hexbyte Glen Cove An updated understanding of how to synthesize value-added chemicals

Hexbyte Glen Cove

Credit: CC0 Public Domain

Researchers have long been interested in finding ways to use simple hydrocarbons, chemicals made of a small number of carbon and hydrogen atoms, to create value-added chemicals, ones used in fuels, plastics, and other complex materials. Methane, a major component of natural gas, is one such chemical that scientists would like to find to ways to use more effectively, since there is currently no environmentally friendly and large-scale way to utilize this potent greenhouse gas.

A new paper in Science provides an updated understanding of how to add onto simple hydrocarbons like methane. Conducted by graduate students Qiaomu Yang and Yusen Qiao, postdoc Yu Heng Wang, and led by professors Patrick J. Walsh and Eric J. Schelter, this new and highly detailed is a crucial step towards designing the next generation of catalysts and finding scalable approaches for turning greenhouse gases into value-added chemicals.

In 2018, a paper published in Science described a mechanism for adding functional groups onto methane, ethane, and other hydrocarbons at room temperature using a cerium-based photocatalyst. The ability to use earth-abundant metals like cerium to create value-added chemicals was an exciting prospect, the researchers say. However, there were aspects of this study that Schelter and his group, who have been working with cerium for a number of years, wanted to understand more thoroughly.

“There were some things in the original paper that we thought were interesting, but we didn’t necessarily agree with the conclusions based on the data that they were reporting,” Schelter says. “We had an idea that what was happening in terms of the mechanism of the reaction, the steps that were involved, and the catalyst that was operative for their chemistry was different from what they were reporting.”

To run the experiments and collect the data they would need to support a new hypothesis, Schelter and Walsh applied for a seed grant from the University of Pennsylvania’s Vagelos Institute for Energy Science and Technology. This funding supported a new collaboration between Schelter and Walsh, allowing the researchers to purchase specialized equipment and hire Yu Heng Wang, a former Penn postdoc who is now an assistant professor at National Tsinghua University in Taiwan.

Thanks to the Vagelos Institute support, the Schelter and Walsh groups were able to combine their complementary expertise in inorganic and and to conduct experiments to obtain data required to propose a new mechanism. This included synthesizing new chemicals, studying reaction rates, looking at how the photocatalyst reacted with different isotopes, and computational analysis. The researchers also isolated the proposed reaction intermediate and were able to obtain its crystal structure, an additional challenge considering that many of the compounds in this study were highly air- and moisture-sensitive.

“We are using conventional techniques to understand the system better and to give a clear mechanism,” Yang says about their approach. “Here, we are mostly using the inorganic perspective with different techniques to understand the mechanisms of the organic reaction. So, it’s a collaboration of inorganic and organic perspectives to understand the mechanism.”

After more than two years of work, the researchers were able to propose a revised mechanism that highlights the essential role of chlorine atoms. While the previous study implicated an alcohol-based intermediate, this latest study found that chlorine radicals, atoms with unpaired electrons that make them highly reactive, form a selective “trap” in the photocatalyst that can give rise to different products.

“I think the hardest part was to understand why the reactivity was happening, and we had to approach that with some unconventional thinking of these intermediate complexes,” says Walsh. “The behavior of the intermediates fits a pattern that people attribute to a radical based on oxygen, but in fact it’s really a chlorine radical that’s the active species, activating the alcohol to make it look like it’s a radical derived from the alcohol.”

Having a detailed understanding of this chemical reaction is a crucial step towards improving existing catalysts and making these and other chemical reactions more efficient. “In order to rationally develop the next generation of catalysts, we have to understand what the current generation is doing,” says Walsh. “With this information, we and others can now build on this revised mechanism and reaction pathway to push the science forward.”

And while there is more work to be done towards finding a fast, scalable reaction for methane transformation, having a detailed understanding of the mechanisms that drive this specific reaction is essential to both reducing greenhouse gas emissions and being able to use methane to create value-added products, the researchers say.

“Chemistry is at its most elegant when we can refine knowledge through expanded insight,” says Schelter. “The contribution here is about getting the right model and using it to advance to the next generation of catalysts that will be even better than the current one.”

More information:
“Photocatalytic C–H activation and the subtle role of chlorine radical complexation in reactivity” Science (2021). science.sciencemag.org/cgi/doi … 1126/science.abd8408

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Hexbyte Glen Cove Understanding SARS-COV-2 proteins is key to improve therapeutic options for COVID-19 thumbnail

Hexbyte Glen Cove Understanding SARS-COV-2 proteins is key to improve therapeutic options for COVID-19

Hexbyte Glen Cove

Transmission electron micrograph of SARS-CoV-2 virus particles isolated from a patient. Credit: NIAID

COVID-19 has had a significant impact since the pandemic was declared by WHO in 2020, with over 3 million deaths and counting, Researchers and medical teams have been hard at work at developing strategies to control the spread of the infection, caused by SARS-COV-2 virus and treat affected patients. Of special interest to the global population is the developments of vaccines to boost human immunity against SARS-COV-2, which are based on our understanding of how the viral proteins work during the infection in host cells. Two vaccines, namely the Pfizer/BioINtech and Oxford/AZ vaccine rely on the use of delivering the gene that encodes the viral spike protein either as an mRNA or through an adenovirus vector to promote the production of relevant antibodies. The use of monoclonal antibodies has also been approved by the US Food and Drug Administration.

It is very clear that provide interesting and potentially effective targets for neutralizing viruses, and SARS-COV-2 is no exception. A recent review published in Current Molecular Medicine presents a summary of SARS-COV-2 proteins. The review, authored by M. E. A. Mohammed (King Khalid University, Saudi Arabia) presents tabular information about 3 major types of SARS-COV-2 proteins: functional proteins (which represent enzymes responsible for , receptor binding, viral invasion and virion assembly and release), (which are associated with the viral protein coat), and accessory proteins (which help in viral replication and virus-host interactions). In addition to informative tables, the review also provides current information about individual proteins in detail in terms of structure and molecular function.

The author points out that SARS-COV-2 proteome consists of proteins that have an increased number of amino acids (nsp3 and spike protein), deleted proteins (orf3b and orf9b) and inserted proteins (orf10). The list of proteins has been compared with variants in SARS-COV and another bat coronavirus species (RATG13). A number of structural and nonstructural proteins of SARS-COV-2 are conserved among the coronavirus species. The list of proteins provides a good starting point for researchers to search for possible pharmaceutical targets for combatting SARS-COV-2 infections.

More information:
Mohammed Elimam Ahamed Mohammed, SARS-CoV-2 proteins: Are they useful as targets for COVID-19 drugs and vaccines?, Current Molecular Medicine (2021). DOI: 10.2174/1566524021666210223143243

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Bentham Science Publishers

Understanding SARS-COV-2 proteins is key to improve therapeutic options for COVID-19 (2021, May 11)
retrieved 12 May 2021
from https://phys.org/news/2021-05-sars-cov-proteins-key-therapeutic-options.html

This docu

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