Chemists from Ural Federal University (UrFU, Ekaterinburg) have suggested a new technique for synthesizing thiophene derivatives and studied their fluorescent properties experimentally as well as theoretically. Many organic compounds containing thiophene rings exhibit a significant pharmacological activity. Thanks to their unusual electronic nature and low aromaticity, thiophenes are an ideal molecule for synthesizing photoactive polymers, liquid crystal and organic dyes for solar cells.
A research group from the UrFU Institute of Chemical Engineering with Italian scientist Scuola Normale published a joint study that showed a new, convenient and effective two-step procedure from producing new thiophene derivatives from simple and easy to obtain starting materials. They determined the features of the mechanism of this reaction using quantum mechanical calculations to compute the reaction thermodynamic parameters, as well as compare the electronic structure of active centers to plot the structure of intermediate substances and to investigate their intramolecular interactions.
The proposed method is promising due to its safe reaction conditions, suggesting that this protocol may provide a valid alternative to previously reported protocols, which are tedious, time-consuming and result in poor yields using dangerous and harsh conditions. Moreover, the new procedure can be used to synthesize libraries of new thiophene derivatives, whose structures will include new combinations of substituents, depending on the requirements of specific applications.
The compound obtained processes important to photophysical properties, in particular, fluorescence, the emission of light by a substance that has absorbed light or other electromagnetic radiation. Molecules and materials with fluorescent properties are of great interest to the field of organic photonics, when creating devices that are luminescent (OLEDS, displays, luminescent probes and labels) and photovoltaic (photodetectors, color-sensitized solar cells). State-of-the-art quantum mechanical methods were used to interpret the experimental results and study the characteristics of the ground and excited states of these new compounds. Due to the photophysical properties and sensitivity to the environment, these synthesized compounds may find applications in many areas, especially in biology, because of their structural similarity with biologically active thiophenes.
The team has proposed a new technique for the synthesis of 4,5-dihydro-1,2,4-triazoles and showed qualities like accessibility, synthetic simplicity, stability and high sensitivity to the microenvironment making these compounds into a convenient platform for creating new sensors.
Based on these results, the researchers prepare to proceed to designing, synthesizing and investigating the fluorescent properties of compounds that are promising candidates for practical use in biology or medicine.
"Our work would not be possible without the funding we received under the UrFU development program and the competitiveness enhancement program (UrFU is a participant in the 5-100 Project). In the conference on organic chemistry, we met the theoretical physicist Enrico Benassi, who became an important member of our team. In order to measure the fluorescence spectra and determine the optical characteristics of synthesized compounds, we had to travel to other institutes in Russia and even to the Nankai University (China). Concrete and effective results appeared only when our institute has purchased new high-quality equipment (a UV spectrophotometer and two Japanese fluorimeters). Thanks to this equipment, our studies have reached the world-level quality and importance of the problems being solved in them, and we have managed to produce publications with high impact factor," says the lead author of the articles, Dr. Nataliya Belskaya, Doctor of Chemistry.
The paper on this research was published in Chemistry – An Asian Journal.