The chemist RUDN suggested how to use transition metals in pharmaceuticals

Transition metals are elements of secondary subgroups of the periodic table. They can form complex compounds that serve as catalysts and stimulate the flow of chemical reactions to obtain 80% of the compounds needed in industry. However, in more "fine" chemistry, for example, in pharmaceuticals, transition metal complexes are not used, although their diversity could advance this field. The fact is that the stability of most transition metal complexes is limited — metals can be washed out of compounds and contaminate the final product. Chemist RUDN together with colleagues from Spain and Italy identified ways to solve this problem.

"We offer a critical review of the issue both from the industry and technology side, and from the economic side. The findings will help to create innovative catalysts for industry and for research purposes," - Rafael Luque, PhD, Head of the research center "Molecular Design and Synthesis of Innovative Compounds for Medicine" RUDN.

Chemists analyzed the existing methods and came to the conclusion that transition metals can be used in pharmaceuticals due to two directions — flow chemistry and metal catalysts of a new generation. Flow chemistry is a new field in the chemistry of heterogeneous catalysis. In this approach, solid particles of the catalyst are "immobilized", and liquid reagents constantly, as on a conveyor, pass by them and undergo transformations. Regardless of the type of catalyst, the particles — whether atoms, enzymes or transition metal complexes - can be fixed to the substrate. If such a design is stable, then the flow will carry away the reaction products, and the catalyst particles will remain on the carrier and will not pollute the final substances. This will serve the development of industrial applications that have not been scaled up in pharmaceuticals and other fields of fine chemistry for about a century.

Chemists cited the example of Chinese colleagues who used a heterogeneous catalyst in the form of carbon nitride mixed with glass beads in the synthesis of cyclobutanes. They managed to obtain an 81% yield of reaction products at room temperature. In another work, chemists from the UK and India used a heterogeneous catalyst and a flow reactor for the industrial synthesis of enzymes. In this experiment, high productivity was maintained for about 30 hours.

"With the combination of flow chemistry and the latest metal catalysts on the substrate, the situation will change quickly. This approach will be able to become widespread, as well as the use of heterogeneous metal nanoparticles," - Rafael Luque, PhD, head of the scientific center "Molecular Design and Synthesis of innovative compounds for Medicine" RUDN.

The results are published in the journal Green Energy & Environment.