X‐Shaped Electroactive Molecular Materials Based on Oligothiophene Architectures: Facile Synthesis and Photophysical and Electrochemical Properties

Abstract

Novel X‐shaped conjugated oligothiophenes, which form a family of well‐defined C4‐substituted compounds with a core thiophene ring that bears four short‐chain branches containing α–α and α–β linkages, have been designed and synthesized by a facile synthetic route. Their optoelectronic properties can be electronically fine‐tuned by manipulating the segments of the branches. In solution, the four compounds show strong photoluminescence with emission maxima located at 459, 491, 494, and 547 nm. The optical properties of their films suggest an interesting conjugated effect in these X‐shaped oligomers. Cyclic‐voltammetry measurements of these compounds have been performed, and corresponding stable polymers from two of the monomers have been prepared by electrochemical polymerization. UV–vis absorption and emission properties of the resultant electroactive polymers are studied, indicating that the optical properties of the 3D polymers could be controlled by repeated potential scans.

From One‐ to Three‐Dimensional Organic Semiconductors: In Search of the Organic Silicon?

“…[66] Liu and co-workers have synthesized X-shaped conjugated systems by attaching short nTs chains at the four positions of a central thiophene ring. [67] Compounds 48 and 49, which absorb at 336 and 383 nm respectively were used as donor in bulk heterojunction solar cells using PCBM as acceptor in a 1:1.2 w/w ratio. Under white light illumination at 100 mW cm -2 the cells gave J sc values of 1.14 and [68] Our group has proposed a different approach based on the use of a bithiophene twisted by steric effects as starting node for building 3D conjugated systems (Fig.…”

Spider‐Like Oligothiophenes

“…Labelled T9 5 [D n ] was prepared according to the reaction sequence reported in Scheme 3, taking advantage of the higher reactivity of the bromine atoms in position a of tetrabromothiophene. [3] Laser-desorption-ionization (LDI) mass spectrometric analysis gave the isotopic distribution in the starting T9 5 [D n ] monomer shown in Table 6. The regioselectivity of the labelling was proven by the nearly total absence in the 1 H NMR spectrum of a signal (dd) at d 7.17 ppm, due to the a' hydrogens of T9 5 .…”

An effective multipurpose building block for 3D electropolymerisation: 2,2′-Bis(2,2′-bithiophene-5-yl)-3,3′-bithianaphthene

“…Thiophene-based oligomers are a virtually boundless class of organic semiconductors and starting materials for preparation of electroactive polymer films [1][2][3][4][5][6][7][8][9][10][11]. Current strategies of molecular design of these oligomers address a trade off between two key requirements [1,12], that is branching, to achieve the solubility required for industrial processing, and planarity, for the most efficient conjugation to achieve the highest conductivity.…”