- Preparation, photophysics, and electrochemistry of segmented comonomers consisting of thiophene and pyrimidine units: New monomers for hybrid copolymers
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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.
- Dufresne, Stephane,Hanan, Garry S.,Skene
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- Design of oligothiophene-based tetrazoles for laser-triggered photoclick chemistry in living cells
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A 405 nm light-activatable terthiophene-based tetrazole was designed that reacts with a fumarate dipolarophile with the second-order rate constant k 2 exceeding 103 M-1 s-1. The utility of this laser-activatable tetrazole in imaging microtubules in a spatiotemporally controlled manner in live cells was demonstrated.
- An, Peng,Yu, Zhipeng,Lin, Qing
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- Spectroelectrochemistry of alternating ambipolar copolymers of 4,4′- and 2,2′-bipyridine isomers and quaterthiophene
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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.
- Zassowski, Pawel,Golba, Sylwia,Skorka, Lukasz,Szafraniec-Gorol, Grazyna,Matussek, Marek,Zych, Dawid,Danikiewicz, Witold,Krompiec, Stanislaw,Lapkowski, Mieczyslaw,Slodek, Aneta,Domagala, Wojciech
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- The liquid crystal Click procedure for oligothiophene-Tethered phthalocyanines-self-Assembly, alignment and photocurrent
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A series of star-shaped liquid crystals (LCs) with a phthalocyanine donor core, oligothiophene antennae and fullerene acceptors have been successfully prepared. This hierarchical self-Assembly results in a nanosegregated helical donor-Acceptor-Antennae LC-system promoted by the recently discovered Click procedure. This model system reveals all photophysical prerequisites for energy conversion, charge generation and transport. Uniform amorphous thin films of 150 nm could be produced by bar-coating. Annealing did not only induce the formation of columns via the Click procedure but also partially homeotropically aligned the non-clearing sample in a sandwich geometry (ITO and Ag/MoO3). This has been confirmed by microscopic studies and the measurement of photocurrent, which increased by a factor of 300 after the annealing step.
- Dechant, Moritz,Fujii, Akihiko,Lehmann, Matthias,Ozaki, Masanori,Uzurano, Genya
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p. 5689 - 5698
(2021/05/17)
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- DIARYLETHENE COMPOUNDS AND USES THEREOF
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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.
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Paragraph 0446
(2014/09/29)
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- Using the nitro group to induce p-stacking in terthiophenes
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A new synthetic route to mononitrated oligothiophenes is described, as well as the preparation of halogenated derivatives (Br, I) thereof. An unusual deep red colour is observed and explained, with the aid of DFT calculations, as arising from a significant quinoidal contribution to the molecular structure. The crystal structures of two compounds, H(C4H2S) 3NO2 and Br(C4H2S) 3NO2, are presented. Both compounds have planar sheets held together by intermolecular short contacts (hydrogen bonds and, for the latter, NO2...Br interactions); the sheets do not directly superimpose, so the effect of the π-stacking is not maximized. Solid-state fluorescence and extended-Hueckel band-structure calculations are also presented for these materials.
- Sears, Wendy A.,MacKinnon, Craig D.,Mawhinney, Robert C.,Sinnemaki, Lauren C.,Johnson, Matthew J.,Winter, A. John,Robertson, Craig M.
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supporting information; experimental part
p. 309 - 317
(2010/07/09)
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- Fluorescence "turn-on" sensing of carboxylate anions with oligothiophene-based o-(carboxamido)trifluoroacetophenones
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(Chemical Equation Presented) o-(Carboxamido)trifluoroacetophenones containing ter- or pentathiophene moiety as a fluorophore exhibit fluorescence enhancement upon binding carboxylate anions. Particularly, the terthiophene derivative shows a large fluorescence enhancement factor (FEF = 120). The enhancement is explained by intramolecular H-bonding stabilization of an anion-ionophore adduct, through which a possible quenching process, the n-π* transition from the trifluoroacetophenone moiety, is eliminated.
- Kim, Dae-Sik,Kyo, Han Ahn
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p. 6831 - 6834
(2008/12/22)
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- Synthesis of thiophene/phenylene co-oligomers. V [1]. Functionalization at molecular terminals toward optoelectronic device applications
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(Chemical Equation Presented) We report the synthesis of various thiophene/phenylene co-oligomers with a total number of thiophene and benzene (phenylene) rings of 5 and 6 with various terminal groups. Those terminal groups have been chosen from among alkyl groups, methoxy groups, trifluoromethyl groups, and cyano groups. The molecular backbone of these compounds comprises phenyl- or biphenylyl-capped thiophene (or oligothiophene) or an alternating co-oligomer. The synthesis is based on either the Suzuki coupling reaction or the Negishi coupling reaction. These reaction schemes enabled us to obtain the target compounds in high quality. In particular, the latter coupling method turned out to produce the compounds at a high yield. The terminal groups are expected to produce various functionalities based upon their electron donating character (alkyl groups and methoxy groups) or electron withdrawing character (trifluoromethyl groups and cyano groups). Additionally some of these groups bring about enhanced solubility. This will lead to the production of a diversity of modified compounds of thiophene/phenylene co-oligomers. To give an example that demonstrates usefulness of the target compounds, we present optoelectronic data that are associated with their device applications.
- Katagiri, Toshifumi,Ota, Satoshi,Ohira, Takayuki,Yamao, Takeshi,Hotta, Shu
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p. 853 - 862
(2008/04/12)
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- PROCESS FOR PRODUCING DENDRIMER, BUILDING BLOCK COMPOUND, AND PROCESS FOR PRODUCING THIOPHENE COMPOUND
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A method for producing a dendrimer having a structural repeating unit which is represented by formula (1) and which contains a linear portion including a thienylene moiety and a branch portion Y formed of an optionally substituted trivalent organic group. The method is based on the convergent method and includes reaction step 1 of converting α-position hydrogen of the thiophene ring of a thienylene-moiety-containing compound (a) for forming end moieties to an active group V1 which undergoes Suzuki cross-coupling reaction, to thereby form compound (b); reaction step 2 of subjecting a compound (c) to Suzuki cross-coupling reaction with the compound (b), to thereby yield compound (d), the compound (c) having a linear portion and a branch portion Y and having, at the branch portion Y, two active groups V2 which undergo Suzuki cross-coupling reaction with the active group V1; reaction step 3 of converting α-position hydrogen of the thiophene ring of the thus-formed compound to an active group V1 which undergoes Suzuki cross-coupling reaction, and reacting the compound (c) with the active group V1, to thereby form a dendron of a subsequent generation; and a step of repeating the reaction step 3 in accordance with needs, to thereby form a dendrimer.
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- Synthesis of Thiophene/phenylene Co-oligomers. IV [1]. 6- to 8-Ring Molecules
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We report the synthesis of various thiophene/phenylene co-oligomers with total number of thiophene and benzene (phenylene) rings of 6 to 8. These compounds include a phenyl-capped sexithiophene, a thienyl-capped quaterphenylene, as well as block and alternating co-oligomers. The synthesis is based on either the Suzuki coupling reaction or the direct dimerization coupling. The latter method produces symmetric molecules with an even total ring number. These reaction schemes enables us to obtain the target compounds in high quality. Although the resulting materials are difficult to dissolve in organic solvents and therefore difficult to identify by usual 1H nmr spectroscopy, they have successfully been identified through Fourier-transform ir spectroscopy. The specific group frequencies of ring-stretching and out-of plane deformation modes are characteristic of the substitution pattern of the individual thiophene and benzene rings.
- Shu, Hotta,Katagiri, Toshifumi
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p. 845 - 850
(2007/10/03)
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- Solvent-free, microwave-assisted synthesis of thiophene oligomers via suzuki coupling
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The purpose of this study was to obtain a rapid, efficient, and environmentally friendly methodology for the synthesis of highly pure thiophene oligomers. The solvent-free, microwave-assisted coupling of thienyl boronic acids and esters with thienyl bromides, using aluminum oxide as the solid support, allowed us to rapidly check the reaction trends on changing times, temperature, catalyst, and base and easily optimize the experimental conditions to obtain the targeted product in fair amounts. This procedure offers a novel, general, and very rapid route to the preparation of soluble thiophene oligomers. Thus, for example, quaterthiophene was obtained in 6 min by reaction of 2-bromo-2,2′-bithiophene with bis(pinacolato)diboron (isolated yield 65%), whereas quinquethiophene was obtained in 11 min by reaction of dibremoterthiophene with thienylboronic acid (isolated yield 74%). The synthesis of new chiral 2,2′-bithiophenes is reported. The detailed analysis of the byproducts of some reactions allowed us to elucidate a few aspects of reaction mechanisms. While the use of microwaves proved to be very convenient for the coupling between conventional thienyl moieties, the same was not true for the coupling of thienyl rings to thienyl-S,S-dioxide moieties. Indeed, in this case, the targeted product was obtained in low yields because of the competitive, accelerated, Diels-Alder reaction that affords a variety of condensation products.
- Melucci, Manuela,Barbarella, Giovanna,Sotgiu, Giovanna
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p. 8877 - 8884
(2007/10/03)
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