Learning by Research

Thesis Title - Exploration of the dimethyldihydropyrene molecular platform for photoswitching, singlet oxygen production and storage. Photostructural correlations.

Recent technological advances have made it possible to eradicate certain diseases, extend life expectancy, travel more easily and communicate with the rest of the world without difficulty. In a society where ecological awareness is now omnipresent, the development of so-called "intelligent" systems based on the use of molecules and in particular photochromic compounds, whose properties can be modulated by light irradiation, seems particularly attractive. Light is a very environmentally-friendly stimulus, easily modulated and inexpensive.

Photoswitches are molecules capable of reversibly oscillating between at least two stable states under the action of light. These compounds are capable of controlling various functions and properties of devices and materials. The best-known use of this type of compound is undoubtedly in the field of optics, with photochromic glasses that are capable of changing hue according to the brightness of the environment. Today, these compounds can be key elements in the fields of energy, electronics, microscopy and medicine. However, while a wide range of these compounds has been developed, most of them require the use of UV light to function. This type of high-energy light is often incompatible with the development of applications in materials science, electronics and, above all, the life sciences.
This thesis work is situated within this context. More specifically, we focused on photochromic molecules with attractive features such as quantitative photoconversion under the effect of red light, but also, in an original way, their ability to convert dioxygen from air to a highly reactive form (singlet oxygen, 1O2) which is of particular interest in the field of phototherapy (light therapy of oncological pathologies).

The work of this thesis was divided into three main areas: I) the fabrication of new highly performant photochromic molecular architectures, II) the determination of the properties of these systems and III) the exploitation of these photochromic compounds for applications in phototherapy and materials science. This multidisciplinary work involved the preparation of compounds by organic synthesis and their spectroscopic characterization. These studies were complemented by theoretical calculations.

Key Words: Photoswitching, Dimethyldihydropyrene, Organic synthesis, Spectroscopy, SF-TD-DFT, Singlet oxygen.

Doctoral School: ED CSV – Chemistry and Life Sciences
Research laboratory: Département de Chimie Moléculaire (DCM - UGA/CNRS)
Thesis supervision: Guy ROYAL and Frédérique LOISEAU

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