Linear and branched electroactive polymers based on ethylenedioxythiophene–triarylamine conjugates

Abstract

Triphenylamines with one, two, or three 3,4-ethylenedioxythiophene (EDOT) substituents attached to the para-phenyl carbons have been prepared via metal-catalyzed cross-coupling reactions. The amines with two or three EDOTs (compounds 4 and 3, respectively) can be oxidatively electropolymerized (via intermolecular coupling between two EDOT groups at their respective a-carbon atoms) to afford stable, linear and cross-linked polymers, respectively. The linear polymer (poly-4) exhibits two resolved, reversible oxidation waves corresponding to the oxidation of the amine and EDOT centers. These two oxidation processes occur at the same potential in cross-linked poly-3 giving rise to one broad, reversible oxidation wave. The observation of redox processes associated with the EDOT-based chromophores contrasts the properties of related (non-EDOTcontaining) polymers for which the thiophene backbone serves only as a conjugated 'linker'. These polymers are highly stable to electrochemical oxidation and can be electrochemically cycled hundreds of times with no detectable decomposition; color changes accompany the redox processes, interconverting between reduced (yellow) and oxidized (green-blue) forms.

Triphenylamine-based multielectrochromic material and its neutral green electrochromic devices

“…Tris [4-(3,4-ethylenedioxythiophene)phenyl]amine (TEPA) is a star-shaped molecular, with three 3,4-ethylenedioxythiophene (EDOT) substituents attached to the para-phenyl carbons of triphenylamine. According to the reports by Chahma et al and Idzik et al, TEPA can be electrochemically synthesized at a much lower potential than that of TPA, and the obtained polymer are distinct from related amine or thiophene polymers due to the observation of redox processes attributable to the EDOT chromophores in addition to the triarylamine-based oxidation [16,17]. However, up to now, there is no detailed report on the electrochromic properties of the poly(tris[4-(3,4-ethylenedioxythiophene)phenyl]amine) (PTEPA) film, not to mention the fabrication of dual type ECDs based on PTEPA and poly (3,4-…”

Redox-State Dependent Spectroscopic Properties of Porous Organic Polymers Containing Furan, Thiophene, and Selenophene

“…The successful formation and characterisation of the polymers was verified by the solid state NMR 13 C cross polarisation (CP) magic-angle spinning (MAS) and 13 C CP non-quaternary suppression (NQS) spectra (Fig. 1).…”

“…The appearance of two peaks is due to the chemical inequivalence of the two carbon positions. The resonance at 140 ppm in the 13 C CP NQS spectra of the furan-containing polymers, POP-O and POP-O1, can be assigned to the quaternary carbons present on the furan ring. In the thiophene and selenophene polymers this peak (along with the alkynyl carbon peaks) was increasingly shifted upfield due to the greater electron density present on the sulfur and selenium atoms when compared with oxygen.…”

“…Solid State NMR The 13 C CPMAS solid state NMR experiments were carried out on a wide-bore Bruker Biospin Avance III solids-300 MHz spectrometer operating at a frequency of 75 MHz for the 13 C nucleus. Approximately 80 mg of sample was placed into 4 mm zirconia rotors fitted with Kel-f caps and spun in a double resonance H-X probehead at 8 kHz MAS (magic angle spinning).…”

“…The efficiency of triarylamines as hole conductors in organic polymers and films has been previously demonstrated where the degree of electron transfer is able to be tuned by variation of the linker between triarylamine cores. [9,10,[12][13][14] Heterocycles such as thiophenes have been demonstrated to provide efficient electron transfer between 'holes' in a system, with high charge carrier mobility in addition to good thermal and photo stabilities. [15,16] Systematic variation in the heterocycle used, from furan through to thiophene and selenophene, is hypothesised to result in increasingly electronically delocalised materials by virtue of the more diffuse orbitals of the heteroatoms further down the periodic table.…”