Guohui Zhang,^a Duxia Cao,^a,* Zhiqiang Liu^b and Guozhong Li^a

^aSchool of Materials Science and Engineering, University of Jinan, Jinan 250022, China
^bState Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
* Corresponding author: E-mail: duxiacao@ujn.edu.cn
Tel.: +86-531-89736751; Fax: +86-531-87974453

Abstract
A new trisubstituted fluorene derivative, 4,4’-{{9-[4-(diethylamino)benzylidene]-9H-fluorene-2,7-diyl}di-2,1- ethenediyl}bis(N,N-diphenyl)benzeneamine (1), with electron-donating N,N-diphenyl-4-vinylaniline group at the 2- and 7-positions, and a N,N-diethyl-4-vinylaniline group as a branch at the 9-position, has been synthesized by a route involving Heck reaction. The photophysical properties of this compound in six different solvents were examined in detail and compared with its non-branched analogue to establish structure-properties relationships. The two-photon absorption coefficient βof the sample was found to be 1.32 × 10^–2 cm GW^–1, determined by a direct nonlinear optical transmission (NLT) method, when pumped by Ti-sapphire laser at 775 nm, which indicates its potential as an optical limiting material.

Keywords: Fluorene, two-photon absorption, optical limiting