Our group offers

One-year contract on

Towards NIR chromophores reversibly photo-switching in water

From Fall 2020 to Fall 2021

Project Description:

Structural changes induced by photo-isomerization are exploited in nature as well as in materials science to develop light-responsive systems. The extensive application of such systems constantly stimulates chemists to develop new photo-isomerizable chromophores for expanding their operating range and targeting specific applications. In this regard, Donor-Acceptor Stenhouse Adducts (DASAs) have been recently introduced as photo-isomerizable dyes displaying photo-induced cyclization between an extended conjugated triene-enol state to a cyclic non-conjugated photo-stationary state. Qualities such as negative photochromism, the possibility to trigger photo-isomerization with near-infrared (NIR) light, and their orthogonality with other photoswitches render DASAs ideal candidates for a broad range of applications. In material science, DASAs found already large use due to their reversible photo-isomerization both in aprotic solvent and polymer matrices. Differently, the lack of reversible photo-isomerization in protic solvents is currently hindering the exploitation of DASAs in bio-applications even if their NIR absorption would be optimal for obtaining in depth photo-isomerization in biological samples.

This project focuses on the design, synthesis and photo-physical characterization of DASAs dyes with the objective of achieving reversible photo-isomerization in protic solvents. Your work will be focused on developing a new DASA library through structural modifications aimed to improve water solubility and achieve reversible photo-switching in protic solvents. Reversible photo-isomerization in aqueous solutions will be tested also by applying supramolecular strategies to favor the stability of the triene-enol form in water. Complexation of DASA will be tested in systems such as cyclodextrins, polymeric assemblies and proteins. The project will be done in close collaboration with members of the group, which will test promising DASA molecules for bio-imaging applications.

 

The skills you will acquire:

Along with strengthening your skills in organic chemistry, you will have the opportunity to acquire knowledge on spectroscopy and photophysical investigation, develop expertise in supramolecular complexation and have an overview of optical microscopy. Your work will be done in collaboration with members of the group in a highly interdisciplinary environment at the interface between chemistry, imaging, and biophysics.

Required background:

The candidate should have a keen interest in molecular organic chemistry and light responsive materials. The candidate must have a M2 degrees in chemistry or equivalent degree and experience in organic synthesis.

Keywords:

Organic chemistry, near-infrared chromophores, photo-isomerization in protic solvents, physical chemistry, spectroscopy, bioimaging.

Contacts:

Dr. Beatrice Adelizzi (Beatrice.Adelizzi@ens.psl.eu), Prof. Ludovic Jullien (Ludovic.Jullien@ens.psl.eu)