Abstract of the project КП-06-Н29/6

In situ irradiation NMR spectroscopy includes illumination of the samples inside the NMR spectrometer. The setup, which includes LEDs as light sources, allows application of whole variety of NMR methods to photochemical reactions. In addition to the standard NMR spectroscopic approaches feasible for reactions in the dark, a special hyperpolarization technique applicable exclusively to photoreactions, the Photo-CIDNP spectroscopy provides a molecular fingerprint of reactive intermediates at a nanosecond time scale.
The present project is focused on the application and development of this methodology on targeting systems with intramolecular proton transfer. These systems are often constituted by a base and a phenolic group being able to establish hydrogen bonds. In such systems, electron transfer (ET) and proton transfer (PT) from a phenol to the basic group can proceed via sequential (ET / PT or PT / ET) or concerted electron-proton transfer (EPT) process. Utilizing timeresolved CIDNP spectroscopy, a method providing detection of short-lived free radical intermediates via their long-lived diamagnetic products, can prove the mechanism of the redox process.
The present project includes the development of new methodology for second type targeting systems with dynamic equilibrium between several possible forms at room temperature (in addition to intramolecular/intermolecular proton transfer), where the standard NMR methods fail to give reliable results.
The compounds that will be investigated include 4-hydroxy-1-naphthaldehydes and 4- hydroxy-3-(piperidin-1-ylmethyl)-1-naphthaldehydes (candidates for a molecular switch based on intramolecular proton transfer), as well as melamine derivatives (suitable for use in luminescent liquid crystals, redox active chromophores, photovoltaic devices, two photon absorption (TPA) materials, and blue phosphorescent OLEDs).