132898-95-4Relevant articles and documents
Preparation, photophysics, and electrochemistry of segmented comonomers consisting of thiophene and pyrimidine units: New monomers for hybrid copolymers
Dufresne, Stephane,Hanan, Garry S.,Skene
, p. 11407 - 11418 (2007)
An efficient coupling route to novel π-conjugated comonomers consisting of pyrimidine, thiophene, and bithiophene units was developed. The novel π-donor-acceptor-donor and π-donor-acceptor-acceptor-donor conjugated compounds were prepared by Suzuki heterocoupling and Ni(0)-mediated Ullman homocoupling reactions. Photophysical investigation of these alternating π-donor and acceptor compounds indicated that the deactivation of their singlet excited State proceeds predominately by fluorescence and results in high fluorescence quantum yields. Intersystem crossing to the triplet state was also present in ca. 10%. Quantification of the triplet manifold by laser flash photolysis further revealed that bithiophene ,produced its triplet state in only 31%. Cyclic voltammetry studies showed that the comonomers undergo both oxidation and reduction leading to their radical cations and radical anions, respectively. The radical cations are highly reactive and undergo anodic polymerization resulting in mutual p- and n-type dopable polymers. The extended conjugation resulting from polymer formation was confirmed by both absorbance and fluorescence spectroscopy and by GPC. Ruthenium binding with the conjugated homocoupled ligand was also found resulting in a hybrid alternating copolymer with significantly different spectroscopic and electrochemical properties relative to its metal-free counterpart.
Spectroelectrochemistry of alternating ambipolar copolymers of 4,4′- and 2,2′-bipyridine isomers and quaterthiophene
Zassowski, Pawel,Golba, Sylwia,Skorka, Lukasz,Szafraniec-Gorol, Grazyna,Matussek, Marek,Zych, Dawid,Danikiewicz, Witold,Krompiec, Stanislaw,Lapkowski, Mieczyslaw,Slodek, Aneta,Domagala, Wojciech
, p. 437 - 452 (2017)
First report of π-conjugated push-pull copolymer systems with 4,4′-bipyridine moieties in the main macromolecular chain is presented. C-substitution pattern of electropolymerisable bithiophene pendants at the 4,4′-bipyridine unit offered the versatility to retain the latter as free amine, or convert it into bipyridylium salt. Both structures have been prepared and investigated, delivering the first example of a polymer with viologen unit making up the extended π-bond. Detailed electrochemical, spectroelectrochemical and quantum chemical study of these new polymer systems and their 2,2′-bipyridine analogues has shown that while linear structure and extended conjugation in the latter help it to accommodate charge carriers characteristic for heavily doped polythiophene, the conjugation break afforded by the meta substitution pattern across the 4,4′-pirydyl unit makes the polymer behave like an ensemble of shorter oligomeric segments with better defined electron transitions and sharper, and faster electrochromic response. Effective π-π interchain coupling between α,ω-bis(2-pyridyl)quaterthiophene repeating units was observed, whereas intramolecular interactions were found to dominate in the linear 2,2′-bipyridyl based polymer. While the bithiophene derivative of methyl viologen electropolymerised less easily than its corresponding non-quaternised derivative, the resulting polymer films demonstrated decent stability when subject to subsequent p- and n-doping, featuring pronounced charge trapping/detrapping signatures. Furthermore, ion pairing between the viologen and weakly basic PF6? and CF3SO3? counterions has been found to impact the redox chemistry of bithiophene functionalised viologen structure. Experimental findings have been confronted with results of quantum chemical computations helping to elucidate the electrochemical and spectroelectrochemical observations made. Presented study delivers insights into the doping processes taking place in conjugation disrupted 4,4'-bipyridine core copolymers, helping to evaluate their potential as substrates for new tuneable π-conjugated polymeric systems.
DIARYLETHENE COMPOUNDS AND USES THEREOF
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Paragraph 0446, (2014/09/29)
A compound according to Formula IA and IB, reversibly convertible under photochromic and electrochromic conditions between a ring-open isomer A and a ring-closed isomer B is provided. For substitutent groups, Z is N, O or S; each R1 is independently selected from the group consisting of H, or halo; each R2 is independently selected from the group consisting of H, halo, a polymer backbone, alkyl or aryl; or, when both R2 together form —CH═CH— and form part of a polymer backbone; each R3 is independently selected from the group consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl; each R4 is aryl; and each R5 is independently selected from the group consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl.
