TY  - JOUR
A1  - Zhao, Yuhang
A1  - Opitz, Andreas
A1  - Eljarrat, Alberto
A1  - Kochovski, Zdravko
A1  - Koch, Christoph
A1  - Koch, Norbert
A1  - Lu, Yan
T1  - Kinetic study on the adsorption of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane on Ag nanoparticles in chloroform
BT  - implications for the charge transfer complex of Ag-F(4)TCNQ
JF  - ACS applied nano materials
N2  - In this study, the kinetics of the adsorption of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F(4)TCNQ) on the surface of Ag nanoparticles (Ag NPs) in chloroform has been intensively investigated, as molecular doping is known to play a crucial role in organic electronic devices. Based on the results obtained from UV-visible (vis)-near-infrared (NIR) absorption spectroscopy, cryogenic transmission electron microscopy, scanning nanobeam electron diffraction, and electron energy loss spectroscopy, a two-step interaction kinetics has been proposed for the Ag NPs and F(4)TCNQ molecules, which includes the first step of electron transfer from Ag NPs to F(4)TCNQ indicated by the ionization of F(4)TCNQ and the second step of the formation of a Ag-F(4)TCNQ complex. The whole process has been followed via UV-vis-NIR absorption spectroscopy, which reveals distinct kinetics at two stages: the instantaneous ionization and the long-term complex formation. The kinetics and the influence of the molar ratio of Ag NPs/F(4)TCNQ molecules on the interaction between Ag NPs and F(4)TCNQ molecules in an organic solution are reported herein for the first time. Furthermore, the control experiment with silica-coated Ag NPs manifests that the charge transfer at the surface between Ag NPs and F(4)TCNQ molecules is prohibited by a silica layer of 18 nm.
KW  - Ag nanoparticles
KW  - F(4)TCNQ
KW  - phase transfer
KW  - kinetics
KW  - electron transfer
KW  - surface interaction
Y1  - 2021
U6  - https://doi.org/10.1021/acsanm.1c02153
SN  - 2574-0970
VL  - 4
IS  - 11
SP  - 11625
EP  - 11635
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Schwarze, Thomas
T1  - Determination of Pd2+ by fluorescence enhancement caused by an off-switching of an energy- and an electron transfer
JF  - ChemistrySelect
N2  - In this paper, we introduce a fluorescent dye 1, which is able to detect selectively Pd2+ by a clear fluorescence enhancement (FE) in THF. In the presence of eight Pd2+ equivalents, we observed a fluorescence enhancement factor (FEF) of 28.3. The high Pd2+ induced FEF can be explained by an off switching of multiple quenching processes within 1 by Pd2+. In the free dye 1 a photoinduced electron transfer (PET) and energy transfer (ET) takes place and quenches the anthracenic fluorescence. The coordination of eight Pd2+ units by the alkylthio-substituted porphyrazine receptor suppresses the PET and ET quenching process and the anthracenic fluorescence is switched on.
KW  - Palladium ion
KW  - electron transfer
KW  - energy transfer
KW  - fluorescence
KW  - porphyrazine
Y1  - 2021
U6  - https://doi.org/10.1002/slct.202003975
SN  - 2365-6549
VL  - 6
IS  - 3
SP  - 318
EP  - 322
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Schwarze, Thomas
A1  - Kelling, Alexandra
A1  - Sperlich, Eric
A1  - Holdt, Hans-Jürgen
T1  - Influence of regioisomerism in 9-anthracenyl-substituted dithiodicyanoethene derivatives on photoinduced electron transfer controlled by intramolecular charge transfer
JF  - ChemPhotoChem
N2  - In this paper, we report on the fluorescence behaviour of three regioisomers which consist of two 9-anthracenyl fluorophores and of differently substituted dithiodicyanoethene moieties. These isomeric fluorescent probes show different quantum yields (phi(f)). In these probes, an oxidative photoinduced electron transfer (PET) from the excited 9-anthracenyl fluorophore to the dithiodicyanoethene unit quenches the fluorescence. This quenching process is accelerated by an intramolecular charge transfer (ICT) of the push-pull pi-electron system of the dithiodicyanoethene group. The acceleration of the PET depends on the strength of the ICT unit. The higher the dipole moment of the ICT unit, the stronger the observed fluorescence quenching. To the best of our knowledge, this is the first report of a regioisomeric influence on an oxidative PET by an ICT.
KW  - anthracene
KW  - charge transfer
KW  - electron transfer
KW  - fluorescence
KW  - isomerism
Y1  - 2021
U6  - https://doi.org/10.1002/cptc.202100070
SN  - 2367-0932
VL  - 5
IS  - 10
SP  - 911
EP  - 914
PB  - Wiley-VCH
CY  - Weinheim
ER  -