@article{BarakDhimanSturmetal.2022, author = {Barak, Arvind and Dhiman, Nishant and Sturm, Floriane and Rauch, Florian and Lakshmanna, Yapamanu Adithya and Findlay, Karen S. and Beeby, Andrew and Marder, Todd B. and Umapathy, Siva}, title = {Excited-State Intramolecular Charge-Transfer Dynamics in 4-Dimethylamino-4′-cyanodiphenylacetylene: An Ultrafast Raman Loss Spectroscopic Perspective}, series = {ChemPhotoChem}, volume = {6}, journal = {ChemPhotoChem}, number = {12}, doi = {10.1002/cptc.202200146}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312280}, year = {2022}, abstract = {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.}, language = {en} }