A joint team of chemists from Tomsk Polytechnic University and St. Petersburg State University has discovered a new technique to control the selectivity of organic reactions by non-valent interactions. It is one of the fundamental problems in organic chemistry, relating to the principles of Green Chemistry. The team used the effects of low-strength non-valent interactions. They used initial substances in powder form, refusing from solution as a medium. It was a fundamental research, however, the team believes that the developed technique will be useful to create next-gen materials, including highly selective sorbents and materials with controlled properties. The paper was published in Organic Chemistry Frontiers (IF: 5,155; Q1), a journal of the Royal Society of Chemistry.
“In organic chemistry, there is a fundamental concept of the reaction selectivity. It is a process of controlling the behavior of reaction components at the molecular level. The fact is that reactions between several organic compounds can proceed in many different directions.
The direction determines the final product and its quantity. The more such variations, the lower the selectivity, and the less the amount of a product. That is why researchers are constantly developing new methods and reagents to obtain the desired product in the shortest possible time and in the simplest possible conditions, in other words with maximum selectivity.
We assumed that we can control selectivity by changing the reaction medium and using non-valent contacts,” Pavel Postnikov, one of the authors of the article and Associate Professor of TPU Research School of Chemistry & Applied Biomedical Sciences, says.
TPU is a leading national research center in hypervalent iodine chemistry, which is highly reactive organic synthesis reagents. In this project, the team experimented with iodonium salts, one of the most popular elements for building compounds that exhibit different type of biological activity. Iodonium saltsare actively used in organic synthesis, and, in particular, they are precursors for production of drugs for the radionuclide diagnostics of oncological disease,” Prof Mekhman Yusubov, head of TPU research team and an author of the article.
The research team of St. Petersburg State University, headed by Vadim Kukushkin Academician of the Russian Academy of Sciences, is one of the leading Russian teams in chemistry of non-classical non-valent interactions. It is the cooperation of two teams that allowed achieving these results.
“The most of reactions in organic chemistry are performed in solutions. We assumed that in the solid phase, when all the initial substances are in a structured state, the reaction could proceed differently since the matter is transformed in a special way in the solid phase. We found that, in this case, iodonium salts could form non-valent interactions. Unlike classic covalent contacts, it is a very weak contact between molecules. In this case, it was the non-valent contacts, that determine reaction direction and obtained target compounds, which differ from what could be obtained in solution,”
Natalia Soldatova, one of the authors and a postdoc of St. Petersburg State University, notes.
In this project, the team demonstrated that there is an alternative to the reaction in solution. Since in the solid phase, the reaction can flow in a different direction and thus with other final products.
In addition, we found that non-valent interactions directly affect this. This is important because classical organic chemistry has always been based on strong covalent contacts. The development of chemistry of non-valent interactions and reaction control techniques, based on these interactions, provides a wide scope for creation of new materials. The creation of new non-valent materials will become a further step in this research,” Pavel Postnikov says.
The research was supported by the Russian Science Foundation.