Symmetry yrtemmyS

Vibrational strong coupling (VSC) has recently been shown to change the rate and chemoselectivity of ground state chemical reactions via the formation of light‐matter hybrid polaritonic states.Our recent observation that vibrational mode symmetry has a large influence on charge transfer reactions under VSC suggested that symmetry considerations could be used to control other types of chemical selectivity. We thus explored the stereoselectivity of the thermal electrocyclic ring‐opening of a cyclobutene derivative, a reaction which follows the Woodward‐Hoffmann rules, under VSC. The direction of the change in stereoselectivity depends on the vibrational mode that is coupled, as do changes in rate and reaction thermodynamics. All this is summarized in a new publication, resulting from a collaboration with Joseph Moran‘s group, that just appeared in Angewandte Chemie in Open Access, but also in our publication page.

Mirrors and nothingness…

An interesting article written by Katrina Krämer just appeared in Chemistry World, about the control of chemical reactions via hybrid-light matter states. It summarizes, via the opinion of some actors of this research field like T.W. Ebbesen, J. Yuen-Zhou or Felipe Herrera, what is known already, what still needs to be understood and what could be the future of the field.

Summer reading

Our latest manuscript has just been accepted for publication in ACS Nano. We are showing that it is possible to enhance both the conductivity and photoconductivity of a p-type semiconductor rr-P3HT that is ultra-strongly coupled to plasmonic modes. In addition, the photoconductivity shows a modified spectral response due to the formation of the hybrid polaritonic states.

Congratulations to all co-authors !

Role of Symmetry in Vibrational Strong Coupling

Our latest paper is online and open access in Angewandte Chemie. We explore and reveal the critical role of molecular symmetry in vibrational strong coupling (VSC) in the case of a charge-transfer (CT) complexation reaction. We show indeed that VSC induces large changes in the equilibrium constant of the mesitylene-I2 CT complex, which can be either enhanced or suppressed depending only on the symmetry of the
vibration coupled to the vacuum electromagnetic field.

 

Thermodynamics of VSC

A new publication appeared last week in Nanophotonics, where we study the evolution of some thermodynamic parameters of a chemical reaction (desilylation of PTA) happening in an optical cavity, under vibrational strong coupling (VSC). In this regime, the enthalpy and entropy of activation, determined from temperature-dependent kinetics studies, vary nonlinearly with the coupling strength whereas, when the same parameters are characterized out of cavity, they are pretty constant. It confirms that changes in the kinetics observed under VSC are only related to the enhanced coupling strength. Those results give more insight into the role of collective strong coupling on the transition state that leads to modified dynamics and branching ratios. See our publications page !

Back to school…

We are pleased to announce that a new publication, in cooperation with Vladimir Torbeev group, has just been accepted in Angewandte Chemie International Edition. This time we applied the concept of strong-coupling induced cooperative effect to a biological molecule, the pepsin, which is a digestive enzyme. When strongly coupling the OH stretching bond of the water surrounding pepsin (and involved in its chemical mechanism), the enzyme activity, characterized by fluorescence spectroscopy, is modified. Being able to alter the energy landscape of biological molecules opens a new and promising way to studies on biochemical reactivity. The paper is open access and has been tagged as VIP paper. You can also download it in our Publications page.

One more for the week-end !

Dr Jino George is now leading his group at IISER Mohali but still collaborating with the lab and we are pleased to announce that our paper, previously on ChemArXiv is now accepted for publication in Angewandte Chemie. It reports the solvolysis of PNPA catalysed by vibrational strong coupling (VSC) under cooperative strong coupling effect between the reactant and the solvent molecules. More precisely, when the solvent and reactant have the same vibrational bands, but only the solvent is at a concentration high enough to be strongly coupled to the cavity mode, the reaction rate is increased by one order of magnitude at room temperature. These results offer an exciting perspective for the control of chemical reactivity under VSC regime.

New publications

We added two more papers in our publications page.

One is a recent review written by two groups of ISIS (ours and Thomas Hermans one), including also three researchers from United-Kingdom and Sweden. It deals with the mechanical separation of chiral objects, in particular at the colloidal scale and the way of achieving it by new methods.

The second presents the results of a collaboration, this time with theoreticians colleagues of the DYNO group at IPMCS and a mathematician from NYU Shangaï. It proposes to control the dynamics of a stochastic system from one thermal equilibrium to another, via some optimized protocols that are tested experimentally on a particle in an optical trap.