New effective method for the synthesis of fluorophores

14:42, November 20, 2017

The research was conducted in collaboration with Professor Enrico Benassi

The new method for the synthesis of thiophene derivatives was developed by the chemists of Ural Federal University. The research team also studied fluorescent properties of thiophene derivatives by experimental and theoretical methods. Many organic substances containing the thiophene cycle show significant pharmacological activity. Due to their unusual electronic nature and low aromaticity, thiophenes are an ideal molecule for the synthesis of photoactive polymers, liquid crystals and organic dyes for solar batteries. The scientists have described their discovery in the article published by the journal Chemistry - An Asian Journal.

‘Our work would be impossible without funding by UrFU development program and the competitiveness enhancement program (UrFU is a participant of the project 5-100). We met with the theoretical physicist Enrico Benassi, who became an important member of our team. In order to measure fluorescence spectra and determine the optical characteristics of synthesized compounds, we had to travel to other institutes in Russia and even to Nankai University in China. Real results appeared only when our institute was able to acquire the necessary equipment (UV spectrophotometer and two Japanese fluorimeters). Thanks to them, our studies have reached the world level, we started to make publications with a high impact factor,’ says the Doctor of Chemistry Natalia Belskaya, the lead author of the article.

The research group of UrFU Department of Organic Synthesis Technology published the results of the joint work with the scientists from Italy (Scuola Normale Superiore, Pisa) and Nazarbayev University (Astana, Kazakhstan). They presented a convenient and effective two-step procedure for obtaining new thiophene derivatives from simple and accessible starting materials. The scientists determined the features of this reaction mechanism with the help of quantum mechanical calculations of the thermodynamic parameters of the reaction, the comparison of charges on active centers, the modeling of the structure of intermediate substances, and the study of their intramolecular interactions.

The proposed method is of interest due to convenient and safe conditions (heating of the original substances in dimethylformamide at the temperature of 80°C for 30-120 minutes). It differs from previously proposed long and labor-intensive though less effective processes. Finally, a new procedure can be applied to obtain libraries of new thiophenes, the structure of which will include new combinations of substituents, depending on the requirements of their subsequent use.

The obtained compounds have an important photophysical property - fluorescence (the absorption of a quantum of light by matter followed by the emission of another quantum that has properties different from the original one). The researcher used the methods of quantum mechanics to interpret the experimental results and study the features of the ground and excited states of the substances.

It should be noted that molecules and materials with fluorescent properties are of great interest for organic photonics when creating luminescent (LEDs and displays, luminescent probes and tags) and photovoltaic devices (photodetectors, color-sensitized solar cells). Due to their photophysical properties and increased sensitivity to the environment, synthesized compounds can find application in many fields, especially in biology, because of their structural similarity with biologically active thiophenes.

The article in the Chemistry - An Asian Journal is the fourth article, published in 2017 by UrFU team of chemists. Previously, they developed a method for the synthesis of 2-aryl-1,2,3-triazoles, discovered and studied their fluorescent properties. In addition, they proposed a new method for the synthesis of 4,5-dihydro-1,2,4-triazoles and showed that accessibility, synthetic simplicity, stability and high sensitivity to the microenvironment make these compounds a convenient platform for creating new sensors. In all publications, the researchers present new original substances with unusual optical properties in solutions, crystalline state or in suspension (nanoparticles).

Based on the results obtained, scientists are going to proceed to design, synthesis and research of fluorescent properties of compounds that can be used in biology, medicine in the future.