Barak, A and Dhiman, N and Sturm, F and Rauch, F and Lakshmanna, YA and Findlay, KS and Beeby, A and Marder, TB and Umapathy, S (2022) Excited-State Intramolecular Charge-Transfer Dynamics in 4-Dimethylamino-4′-cyanodiphenylacetylene: An Ultrafast Raman Loss Spectroscopic Perspective. In: ChemPhotoChem .
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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 �-conjugation, relative orientation/twists of the donor/acceptor entities and polarity of the environment. Herein, 4-dimethylamino-4�-cyanodiphenylacetylene (DACN-DPA), a typical donor-�-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. © 2022 The Authors. ChemPhotoChem published by Wiley-VCH GmbH.
| Item Type: | Journal Article |
|---|---|
| Publication: | ChemPhotoChem |
| Publisher: | John Wiley and Sons Inc |
| Additional Information: | The copyright for this article belongs to the Authors. |
| Department/Centre: | Division of Chemical Sciences > Inorganic & Physical Chemistry Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics |
| Date Deposited: | 17 Oct 2022 07:17 |
| Last Modified: | 17 Oct 2022 07:17 |
| URI: | https://eprints.iisc.ac.in/id/eprint/77460 |
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