TY  - JOUR
A1  - Jay, Raphael Martin
A1  - Eckert, Sebastian
A1  - Vaz da Cruz, Vinicius
A1  - Fondell, Mattis
A1  - Mitzner, Rolf
A1  - Föhlisch, Alexander
T1  - Covalency-driven preservation of local charge densities in a metal-to-ligand charge-transfer excited iron photosensitizer
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - Charge-density rearrangements after metal-to-ligand charge-transfer excitation in an iron photosensitizer are investigated by R. M Jay, A. Fohlisch et al. in their Communication (DOI: 10.1002/anie.201904761). By using time-resolved X-ray absorption spectroscopy, surprising covalency-effects are revealed that inhibit charge-separation at the intra-molecular level. Furthermore, the underlying mechanism is proposed to be generally in effect for all commonly used photosensitizers in light-harvesting applications, which challenges the common perception of electronic charge-transfer.
KW  - charge-transfer
KW  - density functional calculations
KW  - iron
KW  - photochemistry
KW  - X-ray absorption spectroscopy
Y1  - 2019
U6  - https://doi.org/10.1002/anie.201904761
SN  - 1433-7851
SN  - 1521-3773
VL  - 58
IS  - 31
SP  - 10742
EP  - 10746
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Sarhan, Radwan Mohamed
A1  - Koopman, Wouter-Willem Adriaan
A1  - Schuetz, Roman
A1  - Schmid, Thomas
A1  - Liebig, Ferenc
A1  - Koetz, Joachim
A1  - Bargheer, Matias
T1  - The importance of plasmonic heating for the plasmondriven photodimerization of 4-nitrothiophenol
JF  - Scientific Reports
N2  - Metal nanoparticles form potent nanoreactors, driven by the optical generation of energetic electrons and nanoscale heat. The relative influence of these two factors on nanoscale chemistry is strongly debated. This article discusses the temperature dependence of the dimerization of 4-nitrothiophenol (4-NTP) into 4,4′-dimercaptoazobenzene (DMAB) adsorbed on gold nanoflowers by Surface-Enhanced Raman Scattering (SERS). Raman thermometry shows a significant optical heating of the particles. The ratio of the Stokes and the anti-Stokes Raman signal moreover demonstrates that the molecular temperature during the reaction rises beyond the average crystal lattice temperature of the plasmonic particles. The product bands have an even higher temperature than reactant bands, which suggests that the reaction proceeds preferentially at thermal hot spots. In addition, kinetic measurements of the reaction during external heating of the reaction environment yield a considerable rise of the reaction rate with temperature. Despite this significant heating effects, a comparison of SERS spectra recorded after heating the sample by an external heater to spectra recorded after prolonged illumination shows that the reaction is strictly photo-driven. While in both cases the temperature increase is comparable, the dimerization occurs only in the presence of light. Intensity dependent measurements at fixed temperatures confirm this finding.
KW  - enhanced raman-scattering
KW  - charge-transfer
KW  - metal
KW  - nanoparticles
KW  - catalysis
KW  - AU
KW  - 4-nitrobenzenethiol
KW  - aminothiophenol
KW  - photocatalysis
KW  - wavelength
Y1  - 2019
U6  - https://doi.org/10.1038/s41598-019-38627-2
SN  - 2045-2322
VL  - 9
PB  - Macmillan Publishers Limited
CY  - London
ER  -