Synthesis, optical properties and supramolecular order of π-conjugated 2,5-di(alcoxy)phenyleneethynylene oligomers

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• 作者：Griselda Castruita ; Eduardo Arias ; Ivana Moggio ; Fá ; tima Pé ; rez ; Diana Medellí ; n ; Romá ; n Torres ; Ronald Ziolo ; Amelia Olivas ; Emilia Giorgetti ; Maurizio Muniz-Mir ; a
• 关键词：Oligo(phenyleneethynylene)’ ; s ; Supramolecular structure ; Liquid crystals ; Small angle X-ray diffraction ; Optical properties
• 刊名：Journal of Molecular Structure
• 出版年：2009
• 出版时间：12 November 2009
• 年：2009
• 卷：936
• 期：1-3
• 页码：177-186
• 全文大小：2767 K

文摘

Two series of 2,5-di(alkoxy)phenyleneethynylene oligomers were synthesized by Sonogashira–Heck coupling reaction. The chemical structure was corroborated by ¹H, ¹³C, APT, DEPT-135 NMR, Raman, FTIR and MALDI-TOF mass spectrometry. The chemical structure of the molecules has been varied in order to study the effect on the physicochemical and optoelectronic properties of the different chain lengths of the lateral substituents (dodecanoxy and butoxy), of different terminal groups (H, Br and I), of different chain length (3, 5 and 7 repeat units in the main conjugated backbone). The thermal properties were analyzed by DSC, TGA and by temperature-dependent X-ray diffraction. The diffraction studies of the oligomers revealed a crystalline behavior for the butoxy series, while for the dodecanoxy series the X-ray patterns are consistent with a supramolecular organization formed of randomly distributed crystalline domains that exhibit a periodic structure at small angles, indicating the presence of a lamellar order. The optical properties can be modulated within a series by increasing the length of the conjugated oligomer chain. On the contrary, neither the length of the alkoxy substituents nor the terminal groups have effect on the shape of the absorption and emission spectra.