Post-doctoral position (M/F) to study the EPR/time-resolved spectroscopy of diarylethene-functionalized polyoxometallates.

Diarylethenes (DAEs) are very well known for their robust photochromic properties, which include excellent fatigue resistance, thermal reversibility, and high quantum yield. The integration of diarylethenes into molecular cages has revealed unique features like photoresponsive encapsulation and efficient energy transfer. Polyoxometalates (POMs), primarily composed of early transition metals, are distinguished by their diverse structural forms and catalytic prowess, especially in redox reactions. Ritchie et al. have made a significant breakthrough by developing the first POM-DAE molecular cage. This cage contains multiple DAE ligands that undergo sequential electrocyclization post-illumination, confirmed via transient absorption and NMR spectroscopy. The transient absorption studies further disclosed additional photoproducts during the illumination process. These include a charge-separated electron-hole pair of DAE+• and POM- with a lifespan exceeding 200 µ-seconds. This finding suggests that POM-DAE combinations could open new avenues in photocatalytic applications by leveraging these long-lived charge-separated states.

This project will explore detailed photo physics of more such POM-DAE systems along with transient absorption and EPR spectroscopy at Laboratory LASIRe CNRS, France, and in collaboration with Chris Ritchie, Monash University.

EPR spectroscopy will be crucial for understanding the radical intermediates in POM-DAE systems during photochromic reactions. These combined techniques promise to elucidate the complex interactions within the POM-DAE system, shedding light on their potential applications in various fields, including energy conversion and catalysis.

SAMPLE PREPARATION UNDER INERT ATMOSPHERE
POM synthesis
EPR CAMPAINS
TRANSIENT ABSORPTION SPECTROSCOPIES CAMPAINS
DATA TREATMENT

The post-doc is a transversal action in the LASIRE laboratory between the two teams.
The experiment will be launched at C4 (EPR) and C8 (Bâtiment).
All chemical preparations will take place in a newly renovated laboratory.
For transient spectroscopy, the researcher will be supported by the research engineer.