TWISTED INTRAMOLECULAR CHARGE TRANSFER IN STYRYLPENTAFLUOROPHENYL AMINOPYRENE: A DFT AND TDDFT STUDY OF SOLVENT EFFECTS AND MOLECULAR TWISTING DYNAMICS
DOI:
10.29303/ipr.v9i1.543Downloads
Abstract
Twisted intramolecular charge transfer is a key feature of donor–acceptor chromophores, significantly influencing their photophysical behavior. These processes are also central to the design of sensing and optoelectronic materials. In this study, we examine styrylpentafluorophenyl aminopyrene, which links a rigid pentafluorostyryl acceptor to a flexible N, N-dimethylaniline donor. Using density functional theory (DFT) and time-dependent DFT, we optimized ground and excited-state structures, mapped torsional energy surfaces, and explored solvent effects within a dielectric continuum model. The calculations indicate that the pentafluorostyryl unit remains locked in conjugation, while donor twisting through the dimethylaniline group drives the formation of a twisted intramolecular charge transfer (TICT) state. This mechanism reproduces observed solvent-independent absorption and solvent-sensitive fluorescence shifts of about 0.5 eV in polar media. The results place styrylpentafluorophenyl aminopyrene among donor-controlled twisted intramolecular charge transfer systems, while also highlighting how the structural asymmetry of a rigid acceptor and a flexible donor creates a single relaxation pathway. Such design principles can help guide the tuning of charge-transfer emission in functional dyes and related optoelectronic applications. In contrast to previously studied systems, styrylpentafluorophenyl aminopyrene reveals a distinctly donor-controlled mechanism reinforced by a rigid acceptor, establishing a new theoretical basis for predicting twisted intramolecular charge transfer behavior in asymmetric donor–acceptor chromophores.
Keywords:
DFT TDDFT Molecular conformation solvent effect TICTReferences
[1] I. Borges, E. Uhl, L. Modesto-Costa, A. J. A. Aquino, and H. Lischka, “Insight into the Excited State Electronic and Structural Properties of the Organic Photovoltaic Donor Polymer Poly(thieno[3,4-b] thiophene benzodithiophene) by Means of ab Initio and Density Functional Theory,” Journal of Physical Chemistry C, vol. 120, no. 38, pp. 21818–21826, 2016.
[2] I. Borges, A. A. J. Aquino, A. Koehn, W. L. Hase, H. Lischka, and L. X. Chen, “states in organic semiconductors for high-performance solar cells: the PTB1 / PCBM low band gap system. Ab initio modeling of excitonic and charge-transfer states in organic semiconductors: the PTB1 / PCBM low band gap system,” Journal of American Chemical Society, vol. 135, p. 18252−18255, 2013.
[3] R. Ghosh and D. K. Palit, “Effect of Donor-Acceptor Coupling on TICT Dynamics in the Excited States of Two Dimethylamine Substituted Chalcones,” Journal of Physical Chemistry A, vol. 119, no. 45, pp. 11128–11137, 2015.
[4] Z. R. Grabowski, K. Rotkiewicz, and W. Rettig, “Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures,” Chem Rev, vol. 103, no. 10, pp. 3899–4031, 2003.
[5] L. Modesto-Costa and I. Borges, “Discrete and continuum modeling of solvent effects in a twisted intramolecular charge transfer system: The 4-N, N-dimethylaminobenzonitrile (DMABN) molecule,” Spectrochim Acta A Mol Biomol Spectrosc, vol. 201, pp. 73–81, 2018.
[6] K. Tominaga and G. C. Walker, “Femtosecond experiments on solvation dynamics of an anionic probe molecule in methanol,” J Photochem Photobiol A Chem, vol. 87, no. 2, pp. 127–133, 1995.
[7] R. Zheng, M. Cheng, R. Ma, D. Schipper, K. Pichugin, and G. Sciaini, “Solvent effects on the intramolecular charge transfer excited state of 3CzClIPN: a broadband transient absorption study,” Phys. Chem. Chem. Phys., vol. 26, no. 2, pp. 1039–1045, 2024.
[8] A. Singh, M. Kumar, and V. Bhalla, “Regulating the Twisted Intramolecular Charge Transfer and Anti-heavy Atom Effect at Supramolecular Level for Favorable Photosensitizing Activity in Water,” ACS Appl Mater Interfaces, vol. 16, no. 45, pp. 62064–62081, Nov. 2024.
[9] M. Raisch, W. Maftuhin, M. Walter, and M. Sommer, “A mechanochromic donor-acceptor torsional spring,” Nat Commun, vol. 12, no. 1, pp. 1–10, 2021.
[10] R. Hertel, W. Maftuhin, M. Walter, and M. Sommer, “Conformer Ring Flip Enhances Mechanochromic Performance of ansa-Donor-Acceptor-Donor Mechanochromic Torsional Springs,” J Am Chem Soc, 2022.
[11] A. J. Reuss, C. Grünewald, H. Gustmann, J. W. Engels, and J. Wachtveitl, “Three-State Fluorescence of a 2-Functionalized Pyrene-Based RNA Label,” Journal of Physical Chemistry B, vol. 121, no. 14, pp. 3032–3041, 2017.
[12] A. M. El-Zohry, E. A. Orabi, M. Karlsson, and B. Zietz, “Twisted Intramolecular Charge Transfer (TICT) Controlled by Dimerization: An Overlooked Piece of the TICT Puzzle,” Journal of Physical Chemistry A, vol. 125, no. 14, pp. 2885–2894, Apr. 2021.
[13] S. Lee, M. Jen, T. Jang, G. Lee, and Y. Pang, “Twisted intramolecular charge transfer of nitroaromatic push–pull chromophores,” Sci Rep, vol. 12, no. 1, Dec. 2022.
[14] A. Pounder, M. Pavlovic, D. Chow, A. Chen, R. A. Manderville, and S. D. Wetmore, “Photobasicity-Triggered Twisted Intramolecular Charge Transfer of Push-Pull Chromophores.” Jun. 09, 2025.
[15] S. Ludwanowski, D. Hoenders, K. Kalayci, H. Frisch, C. Barner-Kowollik, and A. Walther, “Modular functionalization and hydrogel formation via red-shifted and self-reporting [2+2] cycloadditions,” Chemical Communications, pp. 2–5, 2021.
[16] S. Sasaki, S. Suzuki, K. Igawa, K. Morokuma, and G. I. Konishi, “The K-Region in Pyrenes as a Key Position to Activate Aggregation-Induced Emission: Effects of Introducing Highly Twisted N,N-Dimethylamines,” Journal of Organic Chemistry, vol. 82, no. 13, pp. 6865–6873, 2017.
[17] J. J. Mortensen et al., “GPAW: An open Python package for electronic structure calculations,” Journal of Chemical Physics, vol. 160, no. 9, Mar. 2024.
[18] J. Enkovaara et al., “Electronic structure calculations with GPAW: A real-space implementation of the projector augmented-wave method,” Journal of Physics Condensed Matter, vol. 22, no. 25, 2010.
[19] M. Ernzerhof and G. E. Scuseria, “Assessment of the Perdew-Burke-Ernzerhof exchange-correlation functional,” vol. 110, no. 11, pp. 5029–5036, Mar. 1999.
[20] M. E. Casida, “Time-Dependent Density Functional Response Theory for Molecules,” World Scientific, pp. 155–192, 1995.
[21] M. Walter et al., “Time-dependent density-functional theory in the projector augmented-wave method,” Journal of Chemical Physics, vol. 128, no. 24, 2008.
[22] A. Held and M. Walter, “Simplified continuum solvent model with a smooth cavity based on volumetric data,” Journal of Chemical Physics, vol. 141, no. 17, 2014.
[23] S. Ludwanowski, A. Samanta, S. Loescher, C. Barner-Kowollik, and A. Walther, “A Modular Fluorescent Probe for Viscosity and Polarity Sensing in DNA Hybrid Mesostructures,” Advanced Science, vol. 8, no. 5, Mar. 2021.
[24] Z. He, R. Xue, Y. Lei, L. Yu, and C. Zhu, “Photorelaxation pathways of 4-(N,N-dimethylamino)-4’-nitrostilbene upon S1 excitation revealed by conical intersection and intersystem crossing networks,” Molecules, vol. 25, no. 9, May 2020.
[25] S. Thekku Veedu, D. Raiser, R. Kia, M. Scholz, and S. Techert, “Ultrafast dynamical study of pyrene-N,N-dimethylaniline (PyDMA) as an organic molecular diode in solid state,” Journal of Physical Chemistry B, vol. 118, no. 12, pp. 3291–3297, 2014.
[26] P. B. Coto, L. Serrano-Andrés, T. Gustavsson, T. Fujiwara, and E. C. Lim, “Intramolecular charge transfer and dual fluorescence of 4-(dimethylamino) benzonitrile: Ultrafast branching followed by a two-fold decay mechanism,” Physical Chemistry Chemical Physics, vol. 13, no. 33, pp. 15182–15188, Sep. 2011.
[27] H. Lischka et al., “Multireference Approaches for Excited States of Molecules,” Chemical Reviews, vol. 118, no. 15. American Chemical Society, pp. 7293–7361, Aug. 08, 2018.
[28] L. González, D. Escudero, and L. Serrano-Andrés, “Progress and challenges in the calculation of electronic excited states,” ChemPhysChem, vol. 13, no. 1. Wiley-VCH Verlag, pp. 28–51, Jan. 16, 2012.
[29] A. J. Cohen, P. Mori-Sánchez, and W. Yang, “Insights into current limitations of density functional theory,” Science (1979), vol. 321, no. 5890, pp. 792–794, 2008.
[30] R. Wessling et al., “Phenothiazine‐Based Donor‐Acceptor Polymers as Multifunctional Materials for Charge Storage and Solar Energy Conversion,” Macromol Rapid Commun, vol. 2200699, p. 2200699, 2022.
License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Authors who publish with Indonesian Physical Review Journal, agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution-ShareAlike 4.0 International Licence (CC BY SA-4.0). This license allows authors to use all articles, data sets, graphics, and appendices in data mining applications, search engines, web sites, blogs, and other platforms by providing an appropriate reference. The journal allows the author(s) to hold the copyright without restrictions and will retain publishing rights without restrictions.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgment of its initial publication in Indonesian Physical Review Journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
