Difluorenyl carbo‐Benzenes: Synthesis, Electronic Structure, and Two‐Photon Absorption Properties of Hydrocarbon Quadrupolar Chromophores. Issue 40 (12th August 2015)

• Record Type: Journal Article
• Authors: Baglai , Iaroslav; de Anda‐Villa, Manuel; Barba‐Barba, Rodrigo M.; Poidevin, Corentin; Ramos‐Ortíz, Gabriel; Maraval , Valérie; Lepetit , Christine; Saffon‐Merceron, Nathalie; Maldonado, José‐Luis; Chauvin , Remi
• Is Part Of: Chemistry. Volume 21:Issue 40(2015)
• Page Start: 14186
• Page End: 14195
• Publication Date: 2015-08-12
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201500482
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The synthesis, crystal and electronic structures, and one‐ and two‐photon absorption properties of two quadrupolar fluorenyl‐substituted tetraphenyl <italic>carbo</italic>‐benzenes are described. These all‐hydrocarbon chromophores, differing in the nature of the linkers between the fluorenyl substituents and the <italic>carbo</italic>‐benzene core (CC bonds for <bold>3 a</bold>, CCCC expanders for <bold>3 b</bold>), exhibit quasi–superimposable one‐photon absorption (1PA) spectra but different two‐photon absorption (2PA) cross‐sections <italic>σ</italic><sub>2PA</sub>. <italic>Z</italic>‐scan measurements (under NIR femtosecond excitation) indeed showed that the CC expansion results in an approximately twofold increase in the <italic>σ</italic><sub>2PA</sub> value, from 336 to 656 GM (1 GM=10<sup>−50</sup> cm<sup>4</sup> s molecule<sup>−1</sup> photon<sup>−1</sup>) at <italic>λ</italic>=800 nm. The first excited states of A<sub>u</sub> and A<sub>g</sub> symmetry accounting for 1PA and 2PA, respectively, were calculated at the TDDFT level of theory and used for sum‐over‐state estimations of <italic>σ</italic><sub>2PA</sub>(<italic>λ<sub>i</sub></italic>), in which <italic>λ<sub>i</sub></italic>=2 <italic>hc</italic>/<italic>E<sub>i</sub></italic>, <italic>h</italic> is Planck's constant, <italic>c</italic> is the speed of light, and <italic>E<sub>i</sub></italic> is the energy of the 2PA‐allowed transition. The calculated <italic>σ</italic><sub>2PA</sub> values of 227 GM at 687 nm for <bold>3 a</bold> and 349 GM at 708 nm for <bold>3 b</bold> are in agreement with the <italic>Z</italic>‐scan results.</p> </abstract>