Effects of Two Electron-Donating and/or -Withdrawing Substituents on Two-Photon Absorption for Diphenylacetylene Derivatives

Shota Watanabe; Ayumi Tahara; Tasuku Isozaki; Sho Kinoshita; Ryo Takeuchi; Wataru Kashihara; Tadashi Suzuki

doi:10.1021/acs.jpca.3c02865

Effects of Two Electron-Donating and/or -Withdrawing Substituents on Two-Photon Absorption for Diphenylacetylene Derivatives

J Phys Chem A. 2023 Aug 3;127(30):6204-6212. doi: 10.1021/acs.jpca.3c02865. Epub 2023 Jul 11.

Authors

Shota Watanabe¹, Ayumi Tahara¹, Tasuku Isozaki^{1

2}, Sho Kinoshita¹, Ryo Takeuchi¹, Wataru Kashihara¹, Tadashi Suzuki¹

Affiliations

¹ Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan.
² Division of Natural Sciences, College of Arts and Sciences, J. F. Oberlin University, 3758 Tokiwa-machi, Machida, Tokyo 194-0294, Japan.

PMID: 37433226
DOI: 10.1021/acs.jpca.3c02865

Abstract

Two-photon absorption for diphenylacetylene (DPA) derivatives with two substituents (-OMe and/or -NO₂) at the 4,4'-position was investigated experimentally and theoretically. The two-photon absorption spectra and the two-photon absorption cross-sections σ⁽²⁾ for DPA derivatives were obtained by optical-probing photoacoustic spectroscopy (OPPAS). The simulated two-photon absorption spectra of the DPA derivatives, obtained with the time-dependent density functional theory within the Tamm-Dancoff approximation, agreed well with the experimental ones. The mechanisms for enhancement of the σ⁽²⁾ for centrosymmetric and non-centrosymmetric DPA derivatives were found to be different. The large σ⁽²⁾ for centrosymmetric molecules (DPA-OMeOMe and DPA-NO₂NO₂) results from the magnitude of the transition dipole moment, while for non-centrosymmetric molecules (DPA-OMeNO₂), it is enhanced by the smaller detuning energy. Information on two-photon absorption properties of DPA derivatives obtained in this study will be important for the molecular design of two-photon absorption materials.