TY  - JOUR
A1  - Preitschopf, Tobias
A1  - Sturm, Floriane
A1  - Stroganova, Iuliia
A1  - Lemmens, Alexander K.
A1  - Rijs, Anouk M.
A1  - Fischer, Ingo
T1  - IR/UV Double Resonance Study of the 2‐Phenylallyl Radical and its Pyrolysis Products
JF  - Chemistry – A European Journal
N2  - Isolated 2‐phenylallyl radicals (2‐PA), generated by pyrolysis from a nitrite precursor, have been investigated by IR/UV ion dip spectroscopy using free electron laser radiation. 2‐PA is a resonance‐stabilized radical that is considered to be involved in the formation of polycyclic aromatic hydrocarbons (PAH) in combustion, but also in interstellar space. The radical is identified based on its gas‐phase IR spectrum. Furthermore, a number of bimolecular reaction products are identified, showing that the self‐reaction as well as reactions with unimolecular decomposition products of 2‐PA form several PAH efficiently. Possible mechanisms are discussed and the chemistry of 2‐PA is compared with the one of the related 2‐methylallyl and phenylpropargyl radicals.
KW  - free electron laser
KW  - free jet
KW  - IR spectroscopy
KW  - PAH formation
KW  - radical reactions
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312338
VL  - 29
IS  - 13
ER  - 
TY  - JOUR
A1  - Barak, Arvind
A1  - Dhiman, Nishant
A1  - Sturm, Floriane
A1  - Rauch, Florian
A1  - Lakshmanna, Yapamanu Adithya
A1  - Findlay, Karen S.
A1  - Beeby, Andrew
A1  - Marder, Todd B.
A1  - Umapathy, Siva
T1  - Excited‐State Intramolecular Charge‐Transfer Dynamics in 4‐Dimethylamino‐4′‐cyanodiphenylacetylene: An Ultrafast Raman Loss Spectroscopic Perspective
JF  - ChemPhotoChem
N2  - Photo‐initiated intramolecular charge transfer (ICT) processes play a pivotal role in the excited state reaction dynamics in donor‐bridge‐acceptor systems. The efficacy of such a process can be improved by modifying the extent of π‐conjugation, relative orientation/twists of the donor/acceptor entities and polarity of the environment. Herein, 4‐dimethylamino‐4′‐cyanodiphenylacetylene (DACN‐DPA), a typical donor‐π‐bridge‐acceptor system, was chosen to unravel the role of various internal coordinates that govern the extent of photo‐initiated ICT dynamics. Transient absorption (TA) spectra of DACN‐DPA in n‐hexane exhibit a lifetime of >2 ns indicating the formation of a triplet state while, in acetonitrile, a short time‐constant of ∼2 ps indicates the formation of charge transferred species. Ultrafast Raman loss spectroscopy (URLS) measurements show distinct temporal and spectral dynamics of Raman bands associated with C≡C and C=C stretching vibrations. The appearance of a new band at ∼1492 cm\(^{−1}\) in acetonitrile clearly indicates structural modification during the ultrafast ICT process. Furthermore, these observations are supported by TD‐DFT computations.
KW  - charge transfer
KW  - ultrafast Raman loss spectroscopy
KW  - 4-dimethylamino-4′-cyanodiphenylacetylene
KW  - transient absorption
KW  - TD-DFT
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312280
VL  - 6
IS  - 12
ER  -