Difluorenyl carbo‐Benzenes: Synthesis,Electronic Structure,and Two‐Photon Absorption Properties of Hydrocarbon Quadrupolar Chromophores |
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| Authors: | Dr. Iaroslav Baglai Manuel de Anda‐Villa Rodrigo M. Barba‐Barba Corentin Poidevin Dr. Gabriel Ramos‐Ortíz Dr. Valérie Maraval Dr. Christine Lepetit Dr. Nathalie Saffon‐Merceron Dr. José‐Luis Maldonado Prof. Dr. Remi Chauvin |
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| Affiliation: | 1. CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP 44099, 31077 Toulouse CEDEX 4 (France);2. Université de Toulouse, UPS, ICT‐FR 2599, 31062 Toulouse CEDEX 9 (France);3. Kiev National Taras Shevchenko University, 60 Volodymyrska Str., 01033 Kiev (Ukraine);4. Centro de Investigaciones en óptica A.P. 1‐948, 37000 León, Gto. (México), Fax: (+33)?5‐61‐55‐30‐03 |
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| Abstract: | The synthesis, crystal and electronic structures, and one‐ and two‐photon absorption properties of two quadrupolar fluorenyl‐substituted tetraphenyl carbo‐benzenes are described. These all‐hydrocarbon chromophores, differing in the nature of the linkers between the fluorenyl substituents and the carbo‐benzene core (C?C bonds for 3 a , C?C?C?C expanders for 3 b ), exhibit quasi–superimposable one‐photon absorption (1PA) spectra but different two‐photon absorption (2PA) cross‐sections σ2PA. Z‐scan measurements (under NIR femtosecond excitation) indeed showed that the C?C expansion results in an approximately twofold increase in the σ2PA value, from 336 to 656 GM (1 GM=10?50 cm4 s molecule?1 photon?1) at λ=800 nm. The first excited states of Au and Ag symmetry accounting for 1PA and 2PA, respectively, were calculated at the TDDFT level of theory and used for sum‐over‐state estimations of σ2PA(λi), in which λi=2 hc/Ei, h is Planck’s constant, c is the speed of light, and Ei is the energy of the 2PA‐allowed transition. The calculated σ2PA values of 227 GM at 687 nm for 3 a and 349 GM at 708 nm for 3 b are in agreement with the Z‐scan results. |
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| Keywords: | carbo‐mers charge transfer chromophores density functional calculations nonlinear optics |
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