- Small band gap oligothieno[3,4-b]pyrazines
-
(Chemical Equation Presented) (Graph Presented) The synthesis and the optical and electrochemical properties of thiophene end capped oligo(2,3-alkylthieno[3,4-b]pyrazine)s are presented. The optical absorption rapidly shifts to lower energies with increasing chain length, caused in almost equal amounts by a rise of the HOMO and a lowering of the LUMO levels. The optical band gap of the polymer is estimated to be 1.13 ± 0.07 eV. Extrapolated redox potentials indicate that the polymer is a small band gap p-type material.
- Karsten, Bram P.,Janssen, Rene A. J.
-
-
Read Online
- The effect of changes in π-conjugated terthienyl systems using thienyl and ethylenedioxybenzene functionalized thieno[3,4-b]pyrazine precursors: Multicolored low band gap polymers
-
New classes of thieno[3,4-b]pyrazines containing thienyl and ethylenedioxy phenyl units on electron-withdrawing moieties of π-conjugated terthienyl were synthesized. The effect of structural differences on electrochemical and optoelectronic properties of the resulting polymers was investigated. Changes in the electronic nature of the functional groups enable to tune the electrochemical properties of the π-conjugated terthienyl monomers by lowering oxidation potential from 0.62 V (DTTP) to 0.56 V (DBTP). Spectroelectrochemical analyses revealed that the neutral polymer (PDBTP) is dark green in its neutral state revealing π-π* transitions in two well-separated bands at 410 and 751 nm. The electronic band gap of polymer, defined as the onset of the π-π* transition, is found to be 1.0 eV. Using the thienyl unit instead of ethylenedioxy phenyl, a red shift in the band gap (0.95 eV) is observed. The polymer, PDTTP, exhibits multicolor electrochromism and can be switched between a dark yellow neutral state, a green intermediate state, and a brown oxidized state. PDBTP also shows a multicolored electrochromic behavior with three distinct states: dark green at the neutral state, a brown intermediate state, and a brown-violet oxidized state.
- Tarkuc, Simge,Unver, Elif Kose,Udum, Yasemin Arslan,Tanyeli, Cihangir,Toppare, Levent
-
-
Read Online
- Donor-Acceptor-Donor Thienopyrazines via Pd-Catalyzed C-H Activation as NIR Fluorescent Materials
-
A series of thienopyrazine-based donor-acceptor-donor (D-A-D) near-infrared (NIR) fluorescent compounds were synthesized through a rapid, palladium-catalyzed C-H activation route. The dyes were studied through computational analysis, electrochemical prope
- McNamara, Louis E.,Liyanage, Nalaka,Peddapuram, Adithya,Murphy, J. Scott,Delcamp, Jared H.,Hammer, Nathan I.
-
-
Read Online
- Nitration method of simple and efficient aromatic heterocyclic compound
-
The invention provides a nitration method of a simple and efficient aromatic heterocyclic compound, which is large in width, easy to operate and good in repeatability. By means of the method, high-efficiency nitration of common aromatic compounds is realized, the nitration efficiency is greatly improved, and the simple synthesis of the organic photoelectric material intermediate is realized.
- -
-
Paragraph 0025-0027
(2021/09/08)
-
- Donor-Acceptor-Donor Thienopyrazine-Based Dyes as NIR-Emitting AIEgens
-
Organic Near-Infrared luminophores have found broad application as functional materials, but the development of efficient NIR emitters is still a challenging goal. Here we report on a new class of thieno[3,4-b]pyrazine-based NIR emitting materials with Aggregation Induced Emission (AIE) properties. The dyes feature a donor–acceptor–donor (D?A?D) structure, with a thienopyrazine acceptor core connected to two triarylamine donor groups bearing a tetraphenylethylene (TPE) moiety. Fast and efficient synthesis allowed the modular preparation of three dyes of tunable absorption and emission profiles. These constructs were extensively characterized by spectroscopic studies in different solvents, which revealed intense light-harvesting ability and emissions in the deep-red and NIR region with large Stokes shift values. Remarkably, the dyes exhibited AIE properties, retaining emissive ability in the aggregate state, thus emerging as attractive materials for their potential application in the development of luminescent devices.
- Calamante, Massimo,Coppola, Carmen,Dessì, Alessio,Franchi, Daniele,Goti, Giulio,Mordini, Alessandro,Reginato, Gianna,Sinicropi, Adalgisa,Zani, Lorenzo
-
p. 2655 - 2664
(2021/06/26)
-
- Photocontrolled Synthesis of n-Type Conjugated Polymers
-
Current approaches to synthesize π-conjugated polymers (CPs) are dominated by thermally driven, transition-metal-mediated reactions. Herein we show that electron-deficient Grignard monomers readily polymerize under visible-light irradiation at room temperature in the absence of a catalyst. The product distribution can be tuned by the wavelength of irradiation based on the absorption of the polymer. Conversion studies are consistent with an uncontrolled chain-growth process; correspondingly, chain extension produces all-conjugated n-type block copolymers. Preliminary results demonstrate that the polymerization can be expanded to donor–acceptor alternating copolymers. We anticipate that this method can serve as a platform to access new architectures of n-type CPs without the need for transition-metal catalysis.
- Berl, Alexandra J.,Kalow, Julia A.,Woods, Eliot F.
-
supporting information
p. 6062 - 6067
(2020/02/27)
-
- TRIPHENYLAMINE COMPOUNDS, POLYMERS MADE THEREFROM AND ELECTROCHROMIC DEVICE COMPRISING THE SAME
-
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
- -
-
Paragraph 0173; 0176; 0180-0182
(2018/05/03)
-
- In Situ Oxidation Synthesis of p-Type Composite with Narrow-Bandgap Small Organic Molecule Coating on Single-Walled Carbon Nanotube: Flexible Film and Thermoelectric Performance
-
Although composites of organic polymers or n-type small molecule/carbon nanotube (CNT) have achieved significant advances in thermoelectric (TE) applications, p-type TE composites of small organic molecules as thick surface coating layers on the surfaces of inorganic nanoparticles still remain a great challenge. Taking advantage of in situ oxidation reaction of thieno[3,4-b]pyrazine (TP) into TP di-N-oxide (TPNO) on single-walled CNT (SWCNT) surface, a novel synthesis strategy is proposed to achieve flexible films of TE composites with narrow-bandgap (1.19 eV) small molecule coating on SWCNT surface. The TE performance can be effectively enhanced and conveniently tuned by poly(sodium-p-styrenesulfonate) content, TPNO/SWCNT mass ratio, and posttreatment by various polar solvents. The maximum of the composite power factor at room temperature is 29.4 ± 1.0 μW m?1 K?2. The work presents a way to achieve flexible films of p-type small organic molecule/inorganic composites with clear surface coating morphology for TE application.
- Gao, Caiyan,Chen, Guangming
-
-
- Synthesis and characterization of triphenylamine-based polymers and their application towards solid-state electrochromic cells
-
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.
-
p. 78984 - 78993
(2016/09/09)
-
- π-electron conjugated compound, manufacturing method therefor, and π-electron conjugated polymer obtained using same
-
Provided are a π-electron conjugated polymer having a constitutional unit represented by general formula (2) that is suitable as an electrochromic material that changes from a desired colored state to a decolored state, a new compound that is a raw materi
- -
-
Page/Page column 33
(2013/08/28)
-
- INHIBITORS TARGETING DRUG-RESISTANT INFLUENZA A
-
Provided are compounds according to formula (la) or (lb) as described herein, that are capable of modulating the activity of influenza viruses (e.g., influenza A virus), for example, via interaction with the M2 transmembrane protein, and other similar viroporins. Also provided are methods for treating an influenza A-affected disease state or infection comprising administering a composition comprising one or more compounds according to according to formulas (la') or (lb), as described herein.
- -
-
Paragraph 0407
(2013/06/27)
-
- Novel red-emitting thieno-[3,4-b]-pyrazine derivatives suitable for vacuum evaporation and solution method to fabricate non-doped OLEDs
-
Two novel red-emitting thieno-[3,4-b]-pyrazine-cored molecules with phenyls (TP) or polyphenyls (Müllen type dendron, DTP) as peripheral groups were designed and synthesized. They have large Stokes shifts over 100 nm. DTP is thermally stable with decompos
- Li, Qing,Li, Jiuyan,Yang, Ruixia,Deng, Lijun,Gao, Zhanxian,Liu, Di
-
experimental part
p. 674 - 680
(2012/02/06)
-
- Palladium-catalyzed direct C-H arylation of thieno[3,4-b]pyrazines: Synthesis of advanced oligomeric and polymeric materials
-
The first examples are reported of an efficient regioselective direct C-H arylation of thieno[3,4-b]pyrazine (TP) and its 2,3-dimethyl derivative with bromoalkylthiophenes (BATs), under Heck experimental conditions using Pd(OAc)2/Bu4NBr as the catalytic system, giving rise to a variety of valuable aryl-substituted thienopyrazines. The obtained results suggested that the 2-position of the TP moiety is less reactive towards C-H arylation than the 5-and 7-positions. Moreover, the 3-position of the TP moiety showed almost no significant reactivity when all other positions were arylated. The C-H arylation of 2,3-dimethyl-TP with an excess amount of BATs proceeded smoothly, affording the corresponding diarylated thienopyrazine derivatives in excellent yields, without any additional products. Compared to usual cross-coupling reactions, the present synthetic methodology has been used to prepare interesting donor-acceptor π-conjugated polymeric materials in a facial manner in a simple way. Microwave-assisted polymerization proved to be efficient for obtaining reasonable molecular weight copolymers ranging from 18.8 to 24.3 kg mol-1. Incorporating the thienopyrazine unit into polyhexylthiophene chains affected the photophysical and electrochemical properties. The optical band gaps were estimated to be in the range of 1.63-1.06 eV. All copolymers exhibited a diffraction peak at around 2θ = 5.72° corresponding to a d spacing of 15.43 A, which was assigned to an interchain spacing between polymer main chains similar to that found in P3HT. Moreover, a peak around 2θ = 23.09 (3.84 A) was also observed and is believed to be related to π-π stacking of the polymer backbones.
- Abdo, Nabiha I.,El-Shehawy, Ashraf A.,El-Barbary, Ahmed A.,Lee, Jae-Suk
-
p. 5540 - 5551
(2012/10/30)
-
- Thieno[3,2-b]pyrrolo donor fused with benzothiadiazolo, benzoselenadiazolo and quinoxalino acceptors: Synthesis, characterization, and molecular properties
-
Nitrogen-bridged donor-acceptor multifused dithienopyrrolobenzothiadiazole (DTPBT) and dibenzothiadiazolopyrrolothiophene (DBTPT) were successfully synthesized by intramolecular Cadogan annulation. The electron-deficient benzothiadiazole unit in DTPBT can be converted to benzoselenadiazole and quinoxaline moieties through reduction/cyclization to generate dithienopyrrolobenzoselenadiazole (DTPBSe) and dithienopyrroloquinoxaline (DTPQX), respectively. The nitrogen atoms function as the bridges for covalent planarization to induce intermolecular interaction and intramolecular charge transfer.
- Cheng, Yen-Ju,Chen, Chiu-Hsiang,Ho, Yu-Ju,Chang, Shu-Wei,Witek, Henryk A.,Hsu, Chain-Shu
-
scheme or table
p. 5484 - 5487
(2011/12/22)
-
- Dual functions of a novel low-gap polymer for near infra-red photovoltaics and light-emitting diodes
-
We have synthesised and characterised a new low-gap conjugated polymer, with a broad absorption profile. In blends with a C70 derivative we demonstrate power conversion efficiencies of 0.76%. We show electroluminescence from the polymer peaking at 956 nm, and quantum efficiency of 0.02% in a blend.
- Li, Penglei,Fenwick, Oliver,Yilmaz, Seyfullah,Breusov, Dietrich,Caruana, Daren J.,Allard, Sybille,Scherf, Ullrich,Cacialli, Franco
-
supporting information; experimental part
p. 8820 - 8822
(2011/09/21)
-
- Low band gap conjugated small molecules containing benzobisthiadiazole and thienothiadiazole central units: Synthesis and application for bulk heterojunction solar cells
-
Two novel conjugated low band gap small molecules (SMs), M1 and M2, containing benzobisthiadiazole and thienothiadiazole central units, respectively, were synthesized. Both SMs carried terminal cyanovinylene 4-nitrophenyl at both sides which were connected to the central unit with a thiophene ring. The long-wavelength absorption band was located at 591-643 nm and the optical band gap was 1.62-1.63 eV, which is lower than that of P3HT. These two SMs were investigated as electron donor materials along with PCBM or F as electron acceptors for fabrication of bulk heterojunction (BHJ) organic photovoltaic devices. F is a modified PCBM which has been previously synthesized and used as an electron acceptor for poly(3-hexylthiophene) (P3HT). The power conversion efficiency (PCE) for M1:PCBM, M1:F, M2:PCBM and M2:F was 1.05%, 2.02%, 1.23% and 2.72%, respectively. The higher PCE for the devices with M2 as the electron donor has been related to the improved hole mobility for M2. However, the improved PCE for the devices with F as the electron acceptor has been attributed to the more intense absorption of F in the visible region than that of PCBM and also to the higher open circuit voltage resulting from the higher LUMO level of F. We have also fabricated devices with M2:F cast film from mixed solvents. The PCE for the BHJ devices with the as cast and thermally annealed M2:F (mixed solvents) is 3.34% and 3.65%, respectively.
- Mikroyannidis,Tsagkournos,Sharma,Vijay,Sharma
-
scheme or table
p. 4679 - 4688
(2011/10/13)
-
- Thieno[3,4-b]pyrazine-based low bandgap photovoltaic copolymers: Turning the properties by different aza-heteroaromatic donors
-
A new series of low-bandgap copolymers based on electron-accepting thieno[3,4-b]pyrazine (TPZ) and different electron-donating aza-heteroaromatic units, such as carbazole (CZ), dithieno[3,2-b:2′,3′-d]pyrrole (TPR) and dithieno[3,2-b:2′,3′-e]pyridine (TPY), have been synthesized by Suzuki or Stille coupling polymerization. The resulting copolymers were characterized by NMR, elemental analysis, gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry. UV-vis absorption and cyclic voltammetry measurements show that TPZ-based copolymer with TPR has the best absorption due to the strongest intramolecular charge transfer effect and smallest bandgap. The basic electronic structure of D-A model compounds of these copolymers were also studied by density functional theory (DFT) calculations. The conclusion of calculation agreed also well with the experimental results. The polymer solar cells (PSCs) based on these copolymers were fabricated with a typical structure of ITO/PEDOT:PSS/copolymer: PC71BM/Ca/Al under the illumination of AM 1.5G, 100 mW cm -2. The performance results showed that TPZ-based copolymer with TPR donor segments showed highest efficiency of 1.55% due to enhanced short-circuit current density. The present results indicate that good electronic, optical, and photovoltaic properties of TPZ-based copolymers can be achieved by just fine-tuning the structures of aza-heteroaromatic donor segments for their application in PSCs.
- Peng, Qiang,Liu, Xiangju,Qin, Yuancheng,Zhou, Dan,Xu, Jun
-
scheme or table
p. 4458 - 4467
(2012/06/15)
-
- Synthesis and characterization of bridged bithiophene-based conjugated polymers for photovoltaic applications: Acceptor strength and ternary blends
-
Six of three-component donor-acceptor random copolymers P1-P6, symbolized as (thiophene donor)m -(thiophene acceptor)n, were rationally designed and successfully synthesized by the palladium-catalyzed Stille coupling. The 4H-cyclopenta[2,l-b:3,4-b']dithiophene (CPDT) unit serves as the donor for Pl-P4, while the benzothiadiazole (BT), quinoxaline (QU), dithienoquinoxaline, and thienopyrazine (TP) units are used as the acceptor for P1, P2, P3, and P4, respectively. P5 and P6 are structurally analogous to P1 and P2 except for using the dithieno[3,2-b:2',3'-d]silole (DTS) unit as the donor. Because the band gap lowering ability of the acceptor units in the polymer is in the order TP > BT > QU presumably due to the quinoid form population in the polymers, the optical band gaps can be well adjusted to be 1.2,1.6, and 1.8 eV for P4, P1, and P2, respectively. It is found that the two bridged bithiophene units, CPDT and DTS, have similar steric and electronic effects on the P1 and P5 as well as P2 and P6, respectively, leading to comparable intrinsic properties and device performances. Bulk heterojunction photovoltaic cells based on ITO/PEDOT:PSS/polymer:PC7BM/Ca/Al configuration were fabricated and characterized. Although P4 exhibits the lowest optical band gap, broadest absorption spectrum, and highest mobility, the too low-lying LUMO level hinders the efficient exciton dissociation, resulting in a low PCE of 0.7%. Compared with poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b'] dithiophene)-alt-4,7-(2,l,3-benzothiadiazole)] (PCPDTBT), random copolymer P1 shows more blue-shifted, broader absorption spectrum, comparable mobility, and a higher PCE of 2.0%. In view of the fact that P1 shows a higher band gap with strong absorption in visible region, while PCPDTBT has a lower band gap to mainly absorb NIR light, a BHJ device with the active layer containing ternary blend of PCPDTBT/P1/PC71BM was investigated and achieved an enhanced PCE of 2.5%, which outperforms the devices based on the binary blending systems of PCPDTBT/ PC71BM(PCE = 1.4%)orP1/PC71BM(PCE = 2.0%) under the identical conditions. Such an improvement is ascribed to the complementary absorption and compatible structure of P1 and PCPDTBT polymers.
- Chen, Chiu-Hsiang,Hsieh, Chao-Hsiang,Dubosc, Martin,Cheng, Yen-Ju,Hsu, Chain-Shu
-
scheme or table
p. 697 - 708
(2011/10/08)
-
- Iron(II) complexes containing thiophene-substituted "bispicen" ligands Spin-crossover, ligand rearrangements, and ferromagnetic interactions
-
The synthesis and characterization of three new tetradentate "bispicen-type" ligands containing a substituted thiophene heterocycle are described [2,5-thienyl substituents = H (7), Ph (8), or 2-thienyl (9)]. Iron(II) bis(thiocyanate) coordination complexe
- Cheng, Haojin,Djukic, Brandon,Jenkins, Hilary,Gorelsky, Serge,Lemaire, Martin
-
experimental part
p. 954 - 963
(2011/01/06)
-
- Compound capable of being used in organic layer of organic light emitting device
-
Disclosed is a compound represented by the following formula 1 as a light emitting material: wherein each of R0, R1 and R2 is the same as defined herein. An organic light emitting device including a first electrode, an organic film having one or more layers and a second electrode, laminated successively, is also disclosed. At least one layer of the organic film includes at least one compound represented by formula 1. The organic light emitting device shows excellent characteristics in terms of light emitting efficiency, life time and thermal stability.
- -
-
-
- Synthesis and structural characterization of 2,5-dihalo-3,4- dinitrothiophenes
-
Using new nitration protocols, we have been able to efficiently dinitrate 2,5-dihalothiophenes with yields of ～80-95%. The resulting products 2,5-dibromo-3,4-dinitrothiophene (1), 2,5-dichloro-3,4-dinitrothiophene (2), 2-bromo-5-chloro-3,4-dinitrothiophene (3), as well as the analogous 2-bromo-3,4-dinitrothiophene (4), all crystallize easily allowing their characterization via X-ray crystallography. Crystallization of 1 occurs in the monoclinic space group C2/c with a=14.547(3)A, b=7.3534(15)A, c=10.775(2)A, β=128.89(3)°, and Z=4. Crystallization of 2 occurs in the tetragonal space group I-42d with a=9.9398(14)A, b=9.9398(14)A, c=16.866(3)A, and Z=8. Crystallization of 3 occurs as a pseudo-merohedral twin in the triclinic space group P-1 with a=7.340(5)A, b=8.094(5)A, c=9.112(5)A, α=82.059(5)°, β=66.232(5)°, γ=63.021(5)°, and Z=2. Crystallization of 4 occurs in the triclinic space group P-1 with a=7.1787(14)A, b=7.4092(15)A, c=8.3151(17)A, α=101.67(3)°, β=96.00(3)°, γ=116.13(3)°, and Z=2. The structures of all compounds exhibit the formation of interesting solid-state assemblies due to halogen-bonding interactions between the halogen and nitro groups. Springer Science+Business Media, LLC 2007.
- Wen, Li,Rasmussen, Seth C.
-
p. 387 - 398
(2008/02/05)
-
- 1-N-AMINOBENZIMIDAZOLE DERIVATIVES
-
Provided are 1-N-aminobenzimidazole derivatives represented by the following formula (I): wherein R1 and R2 each represents a substituted or unsubstituted alkyl group or the like, R3, R5 and R6 each represents an alkyl group, alkoxy group, hydrogen atom or the like, R4 represents a substituted or unsubstituted alkyl group or the like, A represents a benzene ring or the like, B represents a hydrogen atom or the like, an n stands for an integer of from 0 to 2, or salts thereof; and medicines containing them. The compounds (I) according to the present invention do not bring about much individual differences in therapeutic effects despite the existence of individual differences in the CYP2C19 activity. At the same dose, they can hence bring about appropriate therapeutic effects for all patients. In addition, they are low in the risk of induction of an interaction or a cancer caused by induction of the CYP1A family. Accordingly, they are useful as peptic ulcer therapeutic agents which are safe and surely bring about therapeutic effects.
- -
-
-
- Thieno[3,4-b]pyrazines: Synthesis, structure, and reactivity
-
A general synthetic route has been developed for the efficient preparation of 2,3-disubstituted thieno[3,4-b]-pyrazines. These methods eliminate problems in the preparation of the precursor 3,4-diaminothiophene and utilize α-diones prepared through the reaction of the appropriate organocuprates with oxalyl chloride. This combination allows the convenient preparation of thieno[3,4-b]pyrazine and its 2,3-disubstituted analogues (where substituent = methyl, hexyl, octyl, decyl, dodecyl, and phenyl) in high yield. Characterization of the structure and reactivity of this class of compounds is also described, including the results of structural, electrochemical, and pKa studies.
- Kenning, Don D.,Mitchell, Kari A.,Calhoun, Tessa R.,Funfar, Melanie R.,Sattler, Daniel J.,Rasmussen, Seth C.
-
p. 9073 - 9076
(2007/10/03)
-
- Alternating donor/acceptor repeat units in polythiophenes. Intramolecular charge transfer for reducing band gaps in fully substituted conjugated polymers
-
This paper describes a method to limit the band gap widening that occurs in fully substituted conjugated polymers. This is done by constructing step growth [AB] polymers where the A-units are electron rich and the B-units are electron deficient. The thiophene-based polymers were prepared by modified Stille polymerizations using Pd(0)/CuI catalyst systems in which aryldibromides were coupled with aryldistannanes. The donor units were N,N′-(bis-tert-butoxycarbonyl)-3,4-diaminothiophene, N,N′-(bis-tert-butoxycarbonyl)-N,N′-(dimethyl)-3,4-diaminothiophene, 3,4-diaminothiophene, or 3,4-dialkoxythiophenes while the acceptor units were 3,4-dinitrothiophene, 3,4-(N-n-butylimido)thiophene, or 3,4-diketone-containing thiophenes. The optical spectra showed λmax values ranging from 400 to 676 nm (solution) and 400-768 (film) for these fully substituted polythiophenes, consistent with significant decreases in the band gaps. Intramolecular charge transfer character between the consecutive units explained the lowering of the band gaps. Two polymer systems based solely on electron deficient thiophenes were prepared via an Ullmann coupling which had optical absorption maxima that were in the range of 300-340 nm; considerably smaller than the λmax values for the donor/acceptor systems. Several model trimers were prepared which had significantly shorter wavelength optical absorptions than their corresponding polymers, thus confirming the need for the extended polymeric backbones.
- Zhang, Qing T.,Tour, James M.
-
p. 5355 - 5360
(2007/10/03)
-
- Poly(2,3-dihexylthienopyrazine). A New Processable Low Band-gap Polyheterocycle
-
A new soluble, low band-gap polymer, poly(2,3-dihexylthienopyrazine) 2b, which is dark blue-black in the neutral state and which becomes transparent light yellow when doped has been prepared; it has a doped film conductivity of 3.6 * 10-2 S cm-1 and a band-gap (film) of ca. 0.95 eV making it one of the lowest band-gap polymers prepared to date.
- Pomerantz, Martin,Chaloner-Gill, Benjamin,Harding, Larry O.,Tseng, John J.,Pomerantz, Wendy J.
-
p. 1672 - 1673
(2007/10/02)
-
