Laboratoire P.A.S.T.E.U.R

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Depopulation of Single-Phthalocyanine Molecular Orbitals upon Pyrrolic-Hydrogen Abstraction on Graphene

ACS Nano 2016, 10, 2010−2016

 

Single-molecule chemistry with a scanning tunneling microscope has preponderantly been performed on metal surfaces. The molecule− metal hybridization, however, is often detrimental to genuine molecular properties and obscures their changes upon chemical reactions. We used graphene on Ir(111) to reduce the coupling between Ir(111) and adsorbed phthalocyanine molecules. By local electron injection from the tip of a scanning tunneling microscope the two pyrrolic H atoms were removed from single phthalocyanines. The detachment of the H atom pair induced a strong modification of the molecular electronic structure, albeit with no change in the adsorption geometry. Spectra and maps of the diff erential conductance combined with density functional calculations unveiled the entire depopulation of the highest occupied molecular orbital upon H abstraction. Occupied π  states of intact molecules are proposed to be emptied via  intramolecular electron transfer to dangling σ states of H-free N atoms.

Interview Christian Amatore : The Electrochemical Society

Christian Amatore has given an interview at The Electrochemical Society in the ECS Podcast context.

 

Ultrafast, sensitive and large-volume on-chip real-time PCR for the molecular diagnosis of bacterial and viral infections

Lab Chip2016, Advance Article

 

To control future infectious disease outbreaks, like the 2014 Ebola epidemic, it is necessary to develop ultrafast molecular assays enabling rapid and sensitive diagnoses. To that end, several ultrafast real-time PCR systems have been previously developed, but they present issues that hinder their wide adoption, notably regarding their sensitivity and detection volume. An ultrafast, sensitive and large-volume real-time PCR system based on microfluidic thermalization is presented herein. The method is based on the circulation of pre-heated liquids in a microfluidic chip that thermalize the PCR chamber by diffusion and ultrafast flow switches. The system can achieve up to 30 real-time PCR cycles in around 2 minutes, which makes it the fastest PCR thermalization system for regular sample volume to the best of our knowledge. After biochemical optimization, anthrax and Ebola simulating agents could be detected in a 7-minute real-time PCR and a 7.5-minute reverse transcription real-time PCR (for 30 PCR cycles), respectively 6.4 and 7.2 times faster than with an off-the-shelf apparatus, while conserving real-time PCR sample volume, efficiency, selectivity and sensitivity. The highspeed thermalization also enabled us to perform sharp melting curve analyses in only 20s and to discriminate amplicons of different lengths by rapid real-time PCR. This real-time PCR microfluidic thermalization system is cost-effective, versatile and can be then further developed for point-of-care, multiplexed, ultrafast and highly sensitive molecular diagnoses of bacterial and viral diseases.

 

Inauguration de l'Institut Pierre-Gilles de Gennes (14 mars 2016)

L'Institut Pierre-Gilles de Gennes pour la Microfluidique, auquel prend part le département de Chimie, a été officiellement inauguré ce lundi 14 mars 2016 en présence de Mme Hidalgo (Maire de Paris), Mme Vallaud-Belkacem (Ministre de l'Enseignement et de la Recherche), M. Mandon (Secrétaire d'Etat chargé de l'ESR) et du Président de la République, M. François Hollande.

 

 
Carbon dioxide transport in molten calcium carbonate occurs through an oxo-Grotthuss mechanism via a pyrocarbonate anion

Nature Chemistry2016, Feb.

 

The reactivity, speciation and solvation structure of CO2 in carbonate melts are relevant both for the fate of carbon in deep geological formations and for its electroreduction to CO, to be used as fuel, by means of solvation in a molten carbonate electrolyte. In particular, the high solubility of CO2 in carbonate melts has been tentatively attributed to the formation of a new carbon species, the pyrocarbonate anion, C2O52-. In this work we study, by _rst principles molecular dynamics simulations, the behaviour of CO2 in molten calcium carbonate. We _nd that pyrocarbonate forms spontaneously and the identity of the CO2 molecule is quickly lost through O2- exchange.

The transport of CO2 in this molten carbonate thus occurs in a fashion similar to the Grotthuss mechanism in water, and is three times faster than molecular diffusion. This shows that Grotthuss- like transport is more general than thought so far.