- Organic Thin-film Solar Cells Using Benzotrithiophene Derivatives Bearing Acceptor Units as Non-Fullerene Acceptors
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New star-shaped non-fullerene acceptors (5Z,5′Z,5′′Z)-5,5′,5′′-((benzo[1,2-b : 3,4-b′ : 5,6-b′′]trithiophene-2,5,8-triyltris(4-octylthiophene-5,2-diyl))tris(methaneylylidene))tris(3-octyl-2-thioxothiazolidin-4-one) (1: BTT-OT-ORD) and 2,2′,2′′-((5Z,5′Z,5′′Z)-((benzo[1,2-b : 3,4-b′ : 5,6-b′′]trithiophene-2,5,8-triyltris(4-octylthiophene-5,2-diyl))tris(methaneylylidene))tris(3-octyl-4-oxothiazolidine-5,2-diylidene))trimalononitrile (2: BTT-OT-OTZDM) with a benzotrithiophene core, alkyl-thiophen units, and acceptor units were designed and synthesized. The HOMO-LUMO levels of 1 and 2 were determined by photoemission spectroscopy and UV-Vis absorption spectroscopy. Binary blend and ternary blend bulk heterojunction (BHJ) organic solar cells with non-fullerene acceptors 1 and 2 were fabricated with the inverted device structures of glass/ITO/ZnO/active_layer/MoO3/Ag. Both binary blend BHJ solar cells with 1 and 2 show lower JSC and larger VOC values than P3HT : PCBM solar cells. On the other hand, ternary blend BHJ organic solar cells, including 10 % of 1, exhibited a larger power conversion efficiency than P3HT : PCBM solar cells because the JSC value was largely improved.
- Matsumoto, Kouichi,Yamashita, Kazuhiro,Sakoda, Yuuki,Ezoe, Hinata,Tanaka, Yuki,Okazaki, Tatsuya,Ohkita, Misaki,Tanaka, Senku,Aoki, Yuki,Kiriya, Daisuke,Kashimura, Shigenori,Maekawa, Masahiko,Kuroda-Sowa, Takayoshi,Okubo, Takashi
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p. 4620 - 4629
(2021/09/10)
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- Thiophene-benzothiadiazole based donor–acceptor–donor (D-A-D) bolaamphiphiles, self-assembly and photophysical properties
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Bolaamphiphilies with D-A-D type π-conjugated rigid cores composed by thiophenes as donors (D) and benzothiadiazole (BTD) as central acceptor (A) have been synthesised. Their self-assemblies and photophysical properties were investigated by polarising optical microscope, differential scanning calorimetry, X-ray diffraction and scanning electron microscopy. Such compounds can self-assemble into honeycomb cylinder mesophases with Colhex?/p6mm and Colsqu/p4mm lattices in their pure states as well as organogels with different morphologies in organic solvents. Their absorption spectra cover nearly the entire visible light range and their band gaps are relatively low. Tetrathiophene BTD based bolaamphilphiles (BT4/n) with higher D/A ratios than the bisthiophene BTD bolaamphilphiles (BT2/n) can self-assemble into more ordered nanostructures in both bulk states and solution. Both the absorption and emission peaks of BT4/n are strongly red shifted. The influence of the molecular conformation, the conjugated core length, as well as the D/A ratio on the self-assemble and photophysical characteristics of such D-A-D bolaamphiphiles are discussed.
- Chang, Qing,Cheng, Xiaohong,Ding, Wei,Ma, Tao,Zhang, Lin
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- Linear and nonlinear optical properties of a quadrupolar carbo-benzene and its benzenic parent: The carbo-merization effect
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Herein, the optical properties of thiophene-functionalized quadrupolar carbo-benzenes and a benzenic parent, of generic structure Th–C[tbnd]C–[core]–C[tbnd]C–Th, Th = R2C4HS, are comparatively investigated. Beyond the previously unknown dioctylthienylethynylbenzene (core = p-C6H4, R = nOct), two bis-dialkylthienylethynyl-carbo-benzenes (core = C18Ph4, R = nOct, nBu) are envisaged for the unique “carbo-aromatic” character of the C18 macrocycle. The three targets were synthesized from the corresponding ethynylthiophenes in 47, 20 and 10% yield, respectively, then characterized by classical methods such as NMR spectroscopy, and X-ray crystallography for one of the carbo-benzenes. Regarding linear and nonlinear optical properties, our results show that the carbo-merization induces a significant shift to lower energies of the one-photon electronic excitations accompanied by an 8-fold increase of the molar extinction coefficient compared to the parent molecule. Intriguingly, these excitations lead to a broad band of photoluminescence comprising decay transitions of the type S1 → S0 but also of the type S2 → S0. This phenomenon of emission from higher excited states, which is contrary to Kasha's rule, is assigned to - or revealed by - a reduction of the internal conversion efficiency between S2 and S1. Two-photon induced transitions are also enhanced, the two-photon absorption cross-section (σ2PA) being in average five times larger for the carbo-benzenes than for their benzene parent in the wavelength range 650–950 nm, with a maximum of σ2PA = 1430 GM (1 GM = 10?50 cm4 s/photon). Beyond a moderate nonlinearity, this comparative study provides quantitative insights about the way carbo-merization or insertion of a π-conjugated macrocycle between chromophoric functions (here thiophene rings) can tune optical properties of organic molecules. The optical properties of the bis-dialkylthienylethynyl-carbo-benzenes are also discussed in regard of recent reports on organic chromophores based on other types of π-conjugated macrocyclic cores.
- Barba-Barba, Rodrigo M.,Chammam, Marwa,Ramos-Ortiz, Gabriel,Listunov, Dymytrii,Velusamy, Jayaramakrishnan,Rodriguez, Mario,Carriles, Ramon,Silva, Carlos,Duhayon, Carine,Kauffmann, Brice,Maraval, Valérie,Chauvin, Remi
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- Rational Design of an Iron-Based Catalyst for Suzuki–Miyaura Cross-Couplings Involving Heteroaromatic Boronic Esters and Tertiary Alkyl Electrophiles
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Suzuki–Miyaura cross-coupling reactions between a variety of alkyl halides and unactivated aryl boronic esters using a rationally designed iron-based catalyst supported by β-diketiminate ligands are described. High catalyst activity resulted in a broad substrate scope that included tertiary alkyl halides and heteroaromatic boronic esters. Mechanistic experiments revealed that the iron-based catalyst benefited from the propensity for β-diketiminate ligands to support low-coordinate and highly reducing iron amide intermediates, which are very efficient for effecting the transmetalation step required for the Suzuki–Miyaura cross-coupling reaction.
- Byers, Jeffery A.,Crockett, Michael P.,Li, Bo,Wong, Alexander S.
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supporting information
p. 5392 - 5397
(2020/03/04)
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- Suzuki-Miyaura coupling catalyzed by a Ni(II) PNP pincer complex: Scope and mechanistic insights
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The nickel(II) pincer complex, [NiCl(PhPNP)] (PhPNP = anion of 2,5-bis(diphenylphosphinomethyl)pyrrole), has been employed as a precatalyst for the Suzuki-Miyaura cross-coupling reaction of aryl halides and boronic acids. Both electron-rich and electron-deficient aromatic bromides were found to undergo coupling with boronic acids in modest yield at elevated temperature in the presence of K3PO4·H2O. Preliminary mechanistic studies of the reaction identified a novel species formulated as the boronate complex, [Ni(OB{OH}{2-tolyl})(PhPNP)], which most likely represents a catalyst deactivation pathway. The productive catalytic cycle was found to be most consistent with a Ni(I)/Ni(III) process where the boronic acid serves as both reductant and nucleophile in the presence of base.
- Madera, Justin,Slattery, Megan,Arman, Hadi D.,Tonzetich, Zachary J.
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- Synthesis and characterization of new D-π-A and A-π-D-π-A type oligothiophene derivatives
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In this work, we present a series of newly synthesized conjugated oligothiophene derivatives, with different numbers of central thiophene units, and different donor/acceptor architectures. Electrochemical and spectroscopic data have also been reported. We used thiophene or bithiophene as central donor core units, 3-octylthiophenes as π-bridge and solubilizing sub-units, and ethyl cyanoacetate or rhodanine moieties as acceptor end groups, in order to get D-π-A and A-π-D-π-A molecular architectures. The length of the synthesized oligothiophenes ranges from three to eight thiophene units, a variety that is sufficient to put in evidence different optical and electrochemical characteristics as well as semiconducting characteristics. Oligothiophene compounds can be regarded not only as models for the study of structure-property relationships relative to polythiophenes, but also they present a large number of applications in the field of organic electronics (i.e.: as donors in bulk-heterojunction solar cells and hole-transporting layer materials in perovskite solar cells, among others).
- Pandolfi, Fabiana,Rocco, Daniele,Mattiello, Leonardo
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supporting information
p. 3018 - 3025
(2019/03/21)
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- TRIPHENYLAMINE COMPOUNDS, POLYMERS MADE THEREFROM AND ELECTROCHROMIC DEVICE COMPRISING THE SAME
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The present invention relates to a triphenylamine compound, to a polymer thereof and to an electrochromic device comprising the same, and specifically, to a triphenylamine compound represented by the chemical formula (1), to a polymer thereof and to an electrochromic device comprising the same. In the chemical formula (1), R, R1, R2, R3, R4, and R5 are as defined in claim 1. The present invention also provides a triphenylamine-based polymer capable of forming a thin film having uniform surface and exhibiting excellent reversibility in the electrochromic characteristics.COPYRIGHT KIPO 2018
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Paragraph 0196; 0199; 0200-0202
(2018/05/03)
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- The Discovery of Citral-Like Thiophenes in Fried Chicken
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The isomers of 3,7-dimethyl-2,6-octadienal, more commonly known together as citral, are two of the most notable natural compounds in the flavor and fragrance industry. However, both isomers are inherently unstable, limiting their potential use in various applications. To identify molecules in nature that can impart the fresh lemon character of citral while demonstrating stability under acidic and thermal conditions has been a major challenge and goal for the flavor and fragrance industry. In the study of fried chicken, several alkyl thiophenecarbaldehydes were identified by gas chromatography-mass spectrometry and gas chromatography-olfactometry that provided a similar citral-like aroma. The potential mechanism of formation in fried chicken is discussed. Furthermore, in order to explore the organoleptic properties of this structural backbone, a total of 35 thiophenecarbaldehyde derivatives were synthesized or purchased for evaluation by odor and taste. Certain organoleptic trends were observed as the length of the alkyl or alkenyl chain increased or when the chain was moved to different positions on the thiophene backbone. The 3-substituted alkyl thiophenecarbaldehydes, specifically 3-butyl-2-thiophenecarbaldehyde and 3-(3-methylbut-2-en-1-yl)-2-thiophenecarbaldehyde, exhibited strong citrus and citral-like notes. Several alkyl thiophenecarbaldehydes were tested in high acid stability trials (4 °C vs 38 °C) and outperformed citral both in terms of maintaining freshness over time and minimizing off-notes. Additional measurements were completed to calculate the odor thresholds for a select group of thiophenecarbaldehydes, which were found to be between 4.7-215.0 ng/L in air.
- Cannon, Robert J.,Curto, Nicole L.,Esposito, Cynthia M.,Payne, Richard K.,Janczuk, Adam J.,Agyemang, David O.,Cai, Tingwei,Tang, Xiao-Qing,Chen, Michael Z.
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p. 5690 - 5699
(2017/07/24)
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- Synthesis and characterization of triphenylamine-based polymers and their application towards solid-state electrochromic cells
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Four novel triphenylamine-based polymers, PJK1, PJK2, PJK3 and PJK4 were successfully synthesized and fully characterized by 1H NMR, UV-VIS spectroscopy, cyclic voltammetry (CV), GPC and spectroelectrochemistry. These polymers are easily soluble in many common organic solvents, which make them appropriate for film deposition via spray-coating. We fabricated electrochromic cells comprising ITO-coated glass/polymer/gel electrolyte/ITO-coated glass and patterned the color change by applying direct current with different voltages. We report herein color changes, from the neutral to oxidized form as follows: for PJK1, orange to dark green; for PJK2, light yellow to reddish brown; for PJK3, light blue to grey; and for PJK4, green to bluish green. The majority of the copolymers exhibited very good thermal stabilities, as evidenced by less than a 5% weight loss in temperatures exceeding 400 °C. To further characterize, we simulated the electrochemical and optical properties, which are good agreement with the experimental data.
- Jeong, Jaemyeng,Kumar, Rangaraju Satish,Naveen, Mergu,Son, Young-A.
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p. 78984 - 78993
(2016/09/09)
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- Synthesis and self-assembly of 5,5′-bis(phenylethynyl)-2,2′-bithiophene-based bolapolyphiles in triangular and square LC honeycombs
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A series of X-shaped 5,5′-bis(phenylethynyl)-2,2′-bithiophene-based bolaamphiphiles bearing two long lateral alkyl chains and two terminal glycerol groups has been synthesized by using Kumada and Sonogashira coupling reactions as key steps. The thermotropic liquid crystalline behavior of these compounds was investigated by POM, DSC and X-ray scattering. With elongation of the lateral alkyl chains two different kinds of liquid crystalline phases with honeycomb structures, ColhexΔ/p6mm, formed by (defective) triangular honeycomb cells, and Colsqu/p4mm with square cells were observed for these compounds. UV and PL measurements indicate fluorescent properties making them potential candidates for application in fluorescence sensor devices.
- Gao, Hongfei,Cheng, Huifang,Yang, Zonghan,Prehm, Marko,Cheng, Xiaohong,Tschierske, Carsten
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supporting information
p. 1301 - 1308
(2015/02/19)
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- Cobalt-Catalyzed Reductive Alkylation of Heteroaryl Bromides: One-Pot Access to Alkylthiophenes, -furans, -selenophenes, and -pyrroles
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A practical and convenient Co-catalyzed alkylation method for the facile introduction of various alkyl chains into organic electronically significant heteroaryl compounds, including thiophenes, furans, selenophenes, and pyrroles, is reported. Under well-optimized reaction conditions, a wide range of alkylated heteroaryl compounds have beeen efficiently prepared in moderate to good isolated yields. Notably, 2- or 3-alkylthiophenes, which play a decisive role in polymer chemistry and organic materials, have been synthesized step-economically for the first time by this reductive-coupling methodology using inexpensive cobalt salts as catalysts. This straightforward synthetic procedure avoids the preparation of moisture-unstable organometallic reagents (RMgX or RZnX) required in conventional alkylation protocols. Various alkyl chains have been introduced into organic, electronically important heteroaryl compounds step-economically through Co-catalyzed reductive alkylation reactions. The resulting alkylheteroarenes are indispensable building blocks for polymer chemistry and π-functional organic materials.
- Cai, Deng-Jhou,Lin, Po-Han,Liu, Ching-Yuan
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supporting information
p. 5448 - 5452
(2015/08/24)
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- Transition between triangular and square tiling patterns in liquid-crystalline honeycombs formed by tetrathiophene-based bolaamphiphiles
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A series of 5,5′′′-diphenyl tetrathiophenes with polar glycerol groups at each end and two lateral flexible chains self-assemble into a series of liquid-crystalline honeycombs, formed by the π-conjugated rods which enclose polygonal prismatic cells filled by the lateral chains. With increasing chain length a discontinuous transition from triangular to square honeycombs takes place. At this transition a periodic honeycomb composed of a mixture of square and triangular cells in a ratio 1:2 was formed at low temperature, whereas at higher temperature a hexagonal columnar phase composed of triangular and randomly distributed rhombic cells, a new kind of cybotactic nematic phase, and also a cybotactic isotropic phase, both composed of square honeycomb fragments, represent the intermediate states. This provides an example of a dynamic self-assembled system where, depending on the molecular mobility, the transition between two periodic structures with different symmetry either leads to an increase of complexity, or to a chaotic regime with reduced order.
- Cheng, Xiaohong,Gao, Hongfei,Tan, Xiaoping,Yang, Xueyan,Prehm, Marko,Ebert, Helgard,Tschierske, Carsten
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p. 3317 - 3331
(2013/07/26)
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- Dithiophene based X-shaped bolaamphiphiles: Liquid crystals with single wall honeycombs and geometric frustration
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A series of 5,5′-diphenyl-2,2′-dithiophene based X-shaped polyphiles with two long lateral alkyl chains and terminal glycerol groups was synthesized and the liquid crystalline phases formed by these compounds were investigated by polarizing microscopy, DSC and XRD. These compounds form square (p4mm and p4gm) and hexagonal (p6mm) columnar LC phases. In these mesophases the molecules organize into polygonal honeycombs where the π-conjugated cores form the walls, fused at the edges by the hydrogen bonding networks between the glycerol units and filled by the lateral alkyl chains. By elongation of these chains, a series of polygonal honeycomb phases with a "single wall" structure, ranging from triangular via square and pentagonal to hexagonal was observed. Most triangular honeycombs appear to be defective and can be considered as mixtures of triangular cylinders with orientationally randomized rhombic cylinders. The transition from this improper triangular honeycomb to the square honeycomb takes place via a disordered isotropic phase. Addition of water to this isotropic phase gives rise to a true triangular honeycomb LC phase. Replacing one of the long lateral chains by a small methyl group leads to honeycombs formed by double walls instead of single walls. UV investigations indicate π-stacking of the aromatic cores organized in the honeycomb walls, which is of interest for the potential application of these materials in self assembled arrays of organic electronic material. This journal is
- Gao, Hongfei,Ye, Yafei,Kong, Leiyang,Cheng, Xiaohong,Prehm, Marko,Ebert, Helgard,Tschierske, Carsten
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p. 10921 - 10931,11
(2020/09/15)
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- Electronic properties of thienylene vinylene oligomers: Synthesis and theoretical study
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(E)-1,2-bis(2-thienyl)vinylene (TV), (E)-1,2-bis (3-octyl-2-thienyl) vinylene (TOV), (E)-1,2-bis(3-(2-ethylhexyl)-2-thienyl)vinylene (T2EHV), and (E)-1,2-bis-[2,2'-bithienyl] vinylene (BTV) have been synthesized by a combination of formylation reaction and Mc Murry dimerization. UV-Vis spectra of BTV showed the longest wavelength absorption, TOV and T2EHV showed a bathochromic shift to the red compared with TV, due to an increment of delocalization of the conjugated p-system as the result of the weakening of the carbon-carbon double bonds of the thienyl rings due to the substitution of one hydrogen by the alkyl group. Based on optical data, the effect of linear and branched alkyl chain and extension of conjugation length on the electronic properties is discussed. 1H, 13C-NMR, UV-Visible, Fluorescence data are discussed and theoretical DFT and TD-DFT calculations of ground state and excited states have been also considered in the analysis and explanation of results. Springer Science+Business Media, LLC 2012.
- Neculqueo,Rojas Fuentes,Lopez,Matute,Vasquez,Martinez
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p. 1751 - 1760
(2013/03/14)
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- Identification and quantification of defect structures in poly(2,5-thienylene vinylene) derivatives prepared via the dithiocarbamate precursor route by means of NMR spectroscopy on 13C-labeled polymers
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During the past decades several synthetic routes toward the low band gap polymer poly(2,5-thienylene vinylene) (PTV) and derivatives have been studied. This study describes an extensive NMR characterization of 13C-labeled 3-octyl-PTV and its precursor polymer prepared via the dithiocarbamate route which is, since stable monomers are available, a promising route toward PTV derivatives. By introducing 13C-labeled vinylene carbons, we were able to characterize these polymers in a quantitative way, taking the end groups and structural polymerization defects, which disturb the conjugated system, into account. Several NMR techniques and the synthesis of model compounds were used to fully assign the proton and carbon chemical shifts. Moreover, the classically used thermal conversion of the precursor toward the conjugated polymer has been compared to a smoother, acid-induced elimination procedure.
- Dilien,Chambon,Cleij,Lutsen,Vanderzande,Adriaensens
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scheme or table
p. 4711 - 4720
(2012/05/20)
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- Multifunctional materials consisting of regioregular poly(3-alkylthiophene)s covalently attached on carbon nanotubes for photovoltaic applications
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Facile ways towards the integration of the regioregular poly(3-alkylthiophene)s onto carbon nanotubes, providing multifunctional materials that combine the extraordinary properties of the carbon nanotubes with those of regioregular poly(3-alkylthiophene)s, are presented.
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- Controlling blend film morphology by varying alkyl side chain in highly coplanar donor-acceptor copolymers for photovoltaic application
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A series of varied length alkyl substituted donor-acceptor (D-A) conjugated copolymers with benzo[1,2-b:4,5-b′]dithiophene (BDT) as donor and thiophene rings attached to both sides of the benzothiadiazole (TBT) moieties as acceptors were designed and synthesized. The optical and electrochemical properties showed that the absorption spectrum, the band gaps, and the energy levels of the copolymers were not affected by the varied substituted alkyls, and all these copolymers showed low band gaps around 1.75 eV. In addition, the morphologies of the blend film between copolymers and PCBM can be fine-tuned by increasing the length of substituted alkyl of the copolymers, changing from pea-like aggregation to interpenetrating network to grain-like aggregation. Bulk heterojunction photovoltaic devices were fabricated by using the copolymers as donors and (6,6)-phenyl C61-butyric acid methyl ester (PC 61BM) or (6,6)-phenyl C71-butyric acid methyl ester (PC71BM) as acceptors. The optimized photovoltaic performances showed the stable open-circuit voltage (Voc) in the range of 0.68 to 0.74 eV, and dramatically increasing short circuit current density (Jsc) by optimizing the blending morphologies of copolymer and PCBM films. The optimized photovoltaic performance with a Voc of 0.70 V, J sc of 7.19 mA/cm2, a fill factor (FF) of 0.52, and a power conversion efficiency (PCE) of 2.88%, was obtained by the copolymer PBDT-TBT-C8 (PBDT-TBT-C8:PC61BM, 1:3 w/w, in CB solution). This is due to its low band gap and interpenetrating network morphology of PBDT-TBT-C8:PC 61BM blend film. The photovoltaic device based on PBDT-TBT-C8:PC 71BM showed a Jsc of 8.6 mA/cm2 and a PCE of 3.15%.
- Li, Yaowen,Chen, Yujin,Liu, Xing,Wang, Zhong,Yang, Xiaoming,Tu, Yingfeng,Zhu, Xiulin
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scheme or table
p. 6370 - 6381
(2012/06/18)
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- A deeper insight into the dithiocarbamate precursor route: Synthesis of soluble poly(thienylene vinylene) derivatives for photovoltaic applications
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The synthesis of, two new poly(thienylene vinylene) derivatives is described, i.e. poly(3-octyl-2,5-thienylene vinylene) (O-PTV) and poly(bis[octylphenyl-2,5-thienylene vinylene]) (BOP-PTV). Both polymers have been prepared via the dithiocarbamate (DTC) precursor route. The polymerization protocol of the monomer toward the precursor polymer has been optimized by the use of different bases, leading to improved reproducibility of the polymerization step. Processability has been guaranteed by the introduction of alkyl side chains. Finally the precursor polymers were converted toward conjugated polymers and they were fully characterized by UV/vis, IR, GPC, and cyclic voltammetry. Bulk heterojunction solar cells with PCBM as acceptor showed promising power conversion efficiencies of 0.80% for BOP-PTV and 0.92% for O-PTV.
- Dilien, Hanne,Palmaerts, Arne,Lenes, Martijn,De Boer, Bert,Blom, Paul,Cleij, Thomas J.,Lutsen, Laurence,Vanderzande, Dirk
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scheme or table
p. 10231 - 10240
(2011/08/03)
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- Iron-catalyzed cross-coupling of alkyl sulfonates with arylzinc reagents
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Iron-catalyzed cross-coupling reactions of primary and secondary alkyl sulfonates with arylzinc reagents proceed smoothly In the presence of excess TMEDA and a concomitant magnesium salt. The arylzinc reagents are prepared from the corresponding aryllithium or magnesium reagents with ZnI2. The In situ formation of alkyl Iodides and consecutive rapid cross-coupling avoids discrete preparation of the unstable secondary alkyl halides and also achieves high product selectivity.
- Ito, Shingo,Fujiwara, Yu-Ichi,Nakamura, Eiichi,Nakamura, Masaharu
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supporting information; experimental part
p. 4306 - 4309
(2009/12/26)
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- Construction of giant porphyrin macrorings self-assembled from thiophenylene-linked bisporphyrins for light-harvesting antennae
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As a model of bacterial photosynthetic light-harvesting antenna, a large number of porphyrin units were organized into barrel-shaped macrorings. Two imidazolylporphyrinatozinc(II) molecules were linked through either unsubstituted thiophenes or 3,4-dioctylthiophenes la and lb, respectively. These structures were spontaneously organized by complementary coordination of the imidazolyl to zinc and produced a series of self-assembled fluorescent polygonal macrorings under high dilution conditions. The ring size increased compared with previous m-phenylene examples. The size distribution was also controlled by the presence of octyl substituents. A wide distribution of macrorings from 7- to > 15-mer was obtained from la, whereas macrorings ranging from 7- to 11-mer with a maximum population focused at the 8-mer were formed with lb. The size distribution was governed by competition between entropy-favored, smaller-ring formation and the enthalpy-favored, less-strained larger macroring. The UV/Vis spectra showed a gradual redshift for the larger rings reflecting an increase in the transition dipole interactions.
- Fujisawa, Kaori,Satake, Akiharu,Hirota, Shun,Kobuke, Yoshiaki
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supporting information; experimental part
p. 10735 - 10744
(2009/12/03)
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- Highly conjugated poly(thiophene)s - Synthesis of regioregular 3-alkylthiophene polymers and 3-alkylthiophene/thiophene copolymers
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Tributyltin derivatives of 2-bromo-3-octylthiophene and 5-bromo-4-octyl-2,2′-bi(thiophene) have been selectively prepared. Condensation reactions in the presence of Pd2(dba)3(CHCl3)/4 PPh3 led to high yields (ca. 90%) of regioregular poly(3-octylthiophene) (Mw = 21.4 × 104, Mw/Mn = 1.48) and poly[4-octylbi(thiophene)] (Mw = 3.8 × 104, Mw/Mn = 1.1). The regioregularity of the head-to-tail (HT) coupling has been determined by 1H NMR, which showed HT > 95% for poly(3-octylthiophene) and HT > 90% for the new poly[4-octylbi(thiophene)]. The conjugation properties of these materials have been characterized by FT-IR and UV/Vis spectroscopy. Compared to the corresponding random polymers, the absorption maxima of the new regular polymers are shifted to higher wavelengths (λmax = 448 and 466 nm, respectively). The mean conjugation length increases with increasing regioregularity of the coupling and with fewer substituents along the conjugated chain. The electroactive properties of the materials have also been studied. The new poly[4-octylbi(thiophene)] shows an oxidation peak at a low potential, and, compared to poly(3-octyl-thiophene), a reduction peak is also observed at a lower potential indicating a higher electron affinity. Both polymers exhibit reversible blue-red electrochromic behavior associated with the reversible redox properties.
- Lere-Porte, Jean-Pierre,Moreau, Joel J. E.,Torreilles, Christophe
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p. 1249 - 1258
(2007/10/03)
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- Novel photoluminescent polymers containing oligothiophene and m-phenylene-1,3,4-oxadiazole moieties: Synthesis and spectroscopic and electrochemical studies
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Three conjugated polymers containing oligothiophene units (from one to three thiophene rings) and aromatic 1,3,4-oxadiazole moieties have been successfully synthesized. The polymer structures were characterized and confirmed by 1H and 13C NMR, FT-IR, and elemental analysis. Thermogravimetric analysis demonstrated that the polymers are highly thermal stable. Tunable absorption (from 342 to 428 nm) and fluorescence (from 411 to 558 nm) properties of polymers were observed: The electrochemical investigation indicated that the LUMO and HOMO energy levels of the new polymers could be adjusted. It was also revealed by the electrochemical analysis that the polymers have good charge injection properties for both p-type and n-type charge carriers, as well as good color tunable luminescence and film-forming properties, which makes them potentially useful for fabricating efficient light-emitting devices.
- Meng,Huang
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p. 3894 - 3901
(2007/10/03)
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- Preparation and characterization of ester functionalized poly(3-alkylthiophene)s
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Soluble ester group substituted polythiophenes and copolymers of substituted polythiophenes with 3-octylthiophene were prepared. The decreased conductivities and blue shifts were observed for the substituted polythiophenes. These results indicate the shortening of conjugating length due to the steric repulsion of the ester substituent.
- Lee,Kim,Rhee
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- Design, Synthesis, and Control of Conducting Polymer Architectures: Structurally Homogeneous Poly(3-alkylthiophenes)
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The full details of a facile synthesis of structurally homogeneous poly(3-alkylthiophenes) (PAT's) is presented.In three steps from 3-bromothiophene, PAT's can be made with complete regiochemical control.We define structurally homogenous as a regiochemically well-defined polymer structure that in our case contains almost exclusively head-to-tail couplings (HT-HT) (2,5-couplings between adjacent thiophene rings).By analysis of the NMR data, our poly(n-butylthiophene) (5a) contains 93percent HT-HT couplings, 98percent of the desired regiochemistry is found in poly(n-hexylthiophene) (5b), 97percent in poly(n-octylthiophene), (5c), and 95percent in poly(n-dodecylthiophene), (5d).Quenching studies on reactive intermediates and 13C NMR data also demonstrate the regiochemical purity of these materials.These PAT's show lower energy absorption maximum shifts of up to 14 nm in solution, 46 nm in the solid state, and other intense lower energy peaks with shifts of up to 129 nm (609 nm) from PAT's prepared by the usual methods.All of these data are indicative of longer mean conjugation lengths.Molecular mechanics and ab initio calculations were performed on model trimers of 3-n-alkylthiophenes and show the relationship between regiochemistry of the trimer and its resultant conformations.The results of these calculations are related to the resultant electrical conductivity in these materials.These poly(3-alkylthiophenes) provide for the first time well-defined structures for the investigation of structure-property relationships in this class of electronic and photonic materials.
- McCullough, Richard D.,Lowe, Renae D.,Jayaraman, Manikandan,Anderson, Deborah L.
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p. 904 - 912
(2007/10/02)
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