E. Suraniti, P. Merzeau, J. Roche, S. Gounel, A. G. Mark, P. Fischer, N. Mano, A. Kuhn
Chemical systems do not allow the coupling of energy from several simple reactions to drive a subsequent reaction, which takes place in the same medium and leads to a product with a higher energy than the one released during the first reaction. Gibbs energy considerations thus are not favorable to drive e.g., water splitting by the direct oxidation of glucose as a model reaction. Here, we show that it is nevertheless possible to carry out such an energetically uphill reaction, if the electrons released in the oxidation reaction are temporarily stored in an electromagnetic system, which is then used to raise the electrons’ potential energy so that they can power the electrolysis of water in a second step. We thereby demonstrate the general concept that lower energy delivering chemical reactions can be used to enable the formation of higher energy consuming reaction products in a closed system.
V. Pirenne, G. Kurtay, S. Voci, L. Bouffier, N. Sojic, F. Robert, D. M. Bassani, Y. Landais.
Eosin-Y (EY)-mediated alkylsulfonyl cyanation of olefins was shown to afford alkylsulfonyl nitriles in good yields. On the basis of transient absorption spectroscopy, the reaction was shown to proceed via photoinduced electron transfer from 3EY* to an O-cyanated derivative of the photocatalyst, formed in situ, with generation of the corresponding sulfinate that is oxidized by EY•+ into a sulfonyl radical. Addition of the latter on the olefin, followed by a radical cyano group transfer, then furnished the nitrile along with a RSO2 radical sustaining the radical chain.
D. Kos, H. P. A. G. Astier, G. D. Martino, J. Mertens, H. Ohadi, D. De. Fazio, D. Yoon, Z. Zhao, A. Kuhn, A. C. Ferrari, C. J. B. Ford, J. J. Baumberg
Nanoactuators are a key component for developing nanomachinery. Here, an electrically driven device yielding actuation stresses exceeding 1 MPa with integrated optical readout is demonstrated. Electrolyte films of 10-nm-thick Al2O3 are sandwiched between graphene and Au electrodes that allow reversible room-temperature solid-state redox producing Al metal and O2 gas in a memristive-type switching device. The resulting high-pressure oxygen microfuel reservoirs are encapsulated under the graphene, swelling to heights of up to 1 μm, which can be dynamically tracked by plasmonic rulers. Unlike in standard memristors where the memristive redox reaction occurs in single or few conductive filaments, the mechanical deformation forces the constant creation of new filaments over the whole area of the inflated film. The resulting on–off resistance ratios are exceptionally high, reaching 108 in some cycles. The synchronization of nanoactuation and memristive switching in these devices is compatible with large-scale fabrication and has potential for precise and electrically monitored actuation technology.
A. de Poulpiquet, B. Goudeau, P. Garrigue, N. Sojic, S. Arbault, T. Doneux, L. Bouffier.
The coupling between electrochemistry and fluorescence confocal laser scanning microscopy (FCLSM) allows deciphering the electrochemical and/or redox reactivity of electroactive fluorophores. This is demonstrated with phenoxazine electrofluorogenic species frequently used in bioassays by mapping the variation of fluorescence intensity with respect to the distance from the electrode. The electrochemical conversion of resorufin dye (RF) to non-fluorescent dihydroresorufin (DH) leads to a sharp decrease of the fluorescence signal in the vicinity of the electrode. In contrast, the direct reduction of resazurin (RZ) to DH leads to an unexpected maximum fluorescence intensity localized further away from the surface. This observation indicates that the initial electron transfer (heterogeneous) is followed by a chemical comproportionation step (homogeneous), leading to the formation of RF within the diffusion layer with a characteristic concentration profile. Therefore, in situ FCLSM affords a direct way to monitor such chemical reactivity in space and to decipher a new redox pathway that cannot be resolved solely by electrochemical means.
Ruigrok, H.J., Arnaud-Cormos D., Hurtier A., Poque-Haro E., Poulletier de Gannes F., Ruffié G., Bonnaudin F, Lagroye I., Sojic N., Arbault S., Lévêque P., Veyret B. and Percherancier Y.
The existence of effects of radiofrequency field exposure at environmental levels on living tissues and organisms remains controversial, in particular regarding potential ‘‘nonthermal’’ effects produced in the absence of temperature elevation. Therefore, we investigated whether TRPV1, one of the most studied thermosensitive channels, can be activated by the heat produced by radiofrequency fields and by some specific nonthermal interaction with the fields. We have recently shown that TRPV1 activation can be assessed in real-time on live cells using the bioluminescence resonance energy transfer technique. Taking advantage of this innovative assay, we monitored TRPV1 thermal and chemical modes of activation under radiofrequency exposure at 1800 MHz using different signals (CW, GSM, UMTS, LTE, Wi-Fi and WiMAX) at specific absorption rates between 8 and 32 W/kg. We showed that, as expected, TRPV1 channels were activated by the heat produced by radiofrequency field exposure of transiently-transfected HEK293T cells, but found no evidence of TRPV1 activation in the absence of temperature elevation under radiofrequency field exposure. There was no evidence either that, at fixed temperature, radiofrequency exposure altered the maximal efficacy of the agonist Capsaicin to activate TRPV1.
A snapshot of the electrochemical reaction layer by using 3 dimensionally resolved fluorescence mapping
Friday, 14 September 2018
A. de Poulpiquet, B. Goudeau, P. Garrigue, N. Sojic, S. Arbault, T. Doneux, L. Bouffier. Chem. Sci. 2018, 9, 6622-6628. The coupling between electrochemistry and fluorescence confocal laser scanning microscopy (FCLSM) allows deciphering the... Read More...
Friday, 14 September 2018
V. Pirenne, G. Kurtay, S. Voci, L. Bouffier, N. Sojic, F. Robert, D. M. Bassani, Y. Landais. Org. Lett. 2018, 20 (15), 4521-4525. Eosin-Y (EY)-mediated alkylsulfonyl cyanation of olefins was shown to afford alkylsulfonyl nitriles in good yields. On... Read More...
C‐Functionalized Cationic Diazaoxatriangulenes: Late‐Stage Synthesis and Tuning of Physicochemical Properties
Friday, 14 September 2018
I. Hernández Delgado, S. Pascal, C. Besnard, S. Voci, L. Bouffier, N. Sojic, J. Lacour. Chem. Eur. J. 2018, 24 (40), 10186-10195. A series of nine C‐functionalized cationic diazaoxa triangulene dyes (DAOTA) has been successfully synthesized and... Read More...