Efficient Synthesis and Electronic Spectra of Unsymmetrical 5,12-Diethynyltetracene Derivatives
Received: 02 July 2015
Accepted after revision: 17 August 2015
16 September 2015 (eFirst)
Unsymmetrical 5,12-diethynyltetracene derivatives were synthesized from tetracenequinone by the addition of two types of ethynyllithium reagents, followed by reductive aromatization with SnCl2. These three-step reactions could be integrated into a one-pot process to give unsymmetrically substituted 5,12-diethynyltetracene derivatives in moderate yields. Some unsymmetrical 5,12-bis(phenylethynyl)tetracene derivatives were synthesized from 5-ethynyl-12-phenylethynyltetracene and iodobenzenes by Sonogashira coupling. This integrated process was applied to the synthesis of a π-extended tetracene dimer. The photophysical properties of these compounds were examined by UV/Vis and fluorescence spectroscopy.