Description du sujet de thèse

Title : DFT insights into light-driven charge accumulation based on Earth-abundant high potential photosensitizers
Keywords : theoretical photochemistry - photoinduced electron transfer - redox potential - potential energy surface
Context : Photoinduced electron transfer is an elementary reaction step of natural photosynthesis and, as such, plays a key role in the conversion of sunlight into biological matter. The transfer of single electrons is nowadays fairly well understood, but the photoinduced transfer and accumulation of multiple electrons has remained extremely challenging, although natural or artificial photosynthesis crucially relies on multi-electron transfer reactions. Against this background, we will develop new concepts for the light-driven accumulation of multiple redox equivalents to unravel its basic operating principles.
Objectives : We will develop new photosensitizers made from abundant transition metals featuring higher reducing power than well-known precious metal-based photosensitizers such as Ru(bpy)32+. We will also develop new molecular electron storage units that help us exploit the concept of redox potential inversion to facilitate the light-driven accumulation of several electrons. The design of high-potential photosensitizers (HiPoPS) based on molybdenum(0) complexes will be guided by computational chemistry. Subsequently and in parallel to the experimental work, novel photosensitizer-acceptor (PS-A) dyads or triads PS-A-PS with acceptors capable of storing up to four electrons will be studied. In a third stage, selected donors (D) will be covalently connected via two Mo(0) HiPoPS to a central acceptor unit, to form molecular pentads D-PS-A-PS-D.
Framework : international collaboration with experimentalists (Katja Heinze, U. Mainz and Oliver Wenger, U. Basel), fully funded by the 2022 Solar-driven chemistry call (ANR project ANR-23-SODR-0001). Three PhD students will be starting simultaneously and will combine their synthetic, spectroscopic and computational efforts to reach the objectives.
Skills : Master 2 in theoretical chemistry or physics, with a particular taste for photochemistry and discussion with experimentalists. Programming skills are a plus (Fortran, python), as well as good written and oral skills in English to ensure efficient communication within the project consortium.

Contexte de travail

The Ph.D. student will be hosted at the LCPQ Toulouse, France (about 30 staff members + 30 doc/postdoc), within the Theoretical and Computational Photochemistry group. The calculations will be performed on the local cluster or on the regional cluster (CALMIP)