Oligothienylenevinylenes incorporating 3,4-ethylenedioxythiophene (EDOT) units

A new series of π-conjugated oligomers based on various combinations of thiophene and EDOT units and double bonds has been synthesized by Wittig-Horner reactions from phosphonate anions carrying EDOT or bis-EDOT units. Optical and electrochemical results evidence the crucial role of the EDOT moiety for modulating the electronic properties of the oligomers. The insertion of bis-EDOT unit in the middle of the molecule leads to a self-rigidification of the conjugated system due to non covalent S?O intramolecular interactions. The strong electron donor effect of the EDOT units explains the determining role of the relative position of the EDOT units on the localization and stabilization of the positive charges in the radical cation or dication states.     

Pd-mediated C-H arylation of EDOT and synthesis of push-pull systems incorporating EDOT

The direct C-H arylation of 3,4-ethylenedioxythiophene (EDOT) is described under Heck-type experimental conditions. This methodology has been used to synthesize a series of push-pull systems containing EDOT units.     

3,4-Ethylenedioxythiophene (EDOT)-based π-conjugated oligomers: Facile synthesis and excited-state properties

A facile synthetic method to produce soluble 3,4-ethylenedioxythiophene (EDOT) oligomers was developed by using iron (III) nitrate nonahydrate as the oxidizing reagent. Two EDOT oligomers, i.e. octomers and octodecamers were obtained as the major products. Their UV–vis absorption, fluorescence at room temperature and 77 K, and triplet transient difference absorption have been measured in CH₂Cl₂ solutions or glassy solutions. With increased conjugation length from EDOT octomers (A) to EDOT octodecamers (B), the UV–vis absorption, fluorescence and the triplet transient difference absorption band shift to longer wavelength. Both the oligomers also exhibit reasonably high efficiency to generate singlet oxygen.     

Copolymerization of Azobenzene-bearing Monomer and 3,4-Ethylenedioxythiophene(EDOT): Improved Electrochemical Performance for Electrochromic Device Applications

In this study,novel electrochromic copolymers of 3,4-ethylenedioxythiophene(EDOT)and(E)-1,2-bis(2-fluoro-4-(4-hexylthiophen-2-yl)phenyl)diazene(M1)with different monomer feed ratios were designed and synthesized electrochemically.Electrochemical and spectroelectrochemical characterizations were performed using voltammetry and UV-Vis-NIR spectrophotometry techniques to test the applicability of copolymers for electrochromic applications.In terms of electrochemical behaviors,addition of an electron-rich EDOT unit into the azobenzenecontaining copolymer increased the electron density on the polymer chain and afforded copolymers with very low oxidation potentials at around0.30 V.While the homopolymers(P1 and PEDOT)exhibited neutral state absorptions centered at 510 and 583 nm,EDOT-bearing copolymers showed red shifted absorptions compared to those of P1 with narrower optical band gaps.In addition,the poor optical contrast and switching times of azobenzene-bearing homopolymer were significantly improved with EDOT addition into the copolymer chain.As a result of the promising electrochromic and kinetic preperties,Co P1.5-bearing single layer electrochromic device that works between purple and light greenish blue colors was constructed and characterized.     

Synthesis and electropolymerization of a perylenebisimide-functionalized 3,4-ethylenedioxythiophene (EDOT) derivative

[reaction: see text] We have developed a convenient and straightforward procedure for the preparation of functionalized 3,4-ethylenedioxythiophene (EDOT) systems by using a new chloromethyl-EDOT derivative as a versatile synthon. Based on this procedure, novel suitably functionalized perylenetetracarboxylic diimide (PDI) dye derivatives covalently linked to 3,4-ethylenedioxythiophene moieties have been synthesized and electrochemically polymerized to yield a donor-acceptor PEDOT derivative with an enhanced absorption cross-section.     

Electrosynthesis and characterization of poly(hydroxy-methylated-3,4-ethylenedioxythiophene) film in aqueous micellar solution and its biosensing application

A new and efficient synthetic route to hydroxymethylated-3,4-ethylenedioxylthiophene（EDOT-MeOH） was developed by a simple four-step sequence,and its global yield was approximately 41.06%.The poly（hydroxymethylated-3, 4-ethylenedioxylthiophene）（PEDOT-MeOH） film was electrosynthesized in aqueous sodium dodecylsulfate micellar solutions and characterized by different methods.The EDOT-MeOH possessed better water solubility,and lower onset oxidation potential than EDOT.The as-obtained PEDOT-MeOH film displayed good reversible redox activity,stability and capacitance properties in a monomer-free electrolyte,especially the good solubility of PEDOT-MeOH film in strong polar organic solvents such as dimethyl sulfoxide and tetrahydrofuran created a potential application in many different fields. Fluorescent spectra indicated that PEDOT-MeOH was a yellow-green-light-emitter with maximum emission at 568 nm.The as-formed PEDOT-MeOH film had good biocompatibility and was used for fabricating the electrochemical vitamin C biosensor.The proposed biosensor showed a linear range of 3×10^-6 mol/L to 1.2×10^-2 mol/L with the detection limit of 1μmol/L,a sensitivity of 95.6μA（mmol/L）^-1 cm^-2,and a current response time less than 10 s and a fairly good stability (The relative standard deviation was 0.43%for 20 successive assays,the proposed biosensor still retained 93.5%of bioactivity after 15 days storage.This result indicated that the prepared PEDOT-MeOH film as immobilization matrix of biologically-active species could be a promising candidate for the design and application of biosensor.     

Utilizing 3,4-ethylenedioxythiophene(EDOT)-bridged non-fullerene acceptors for efficient organic solar cells

A rational design of efficient low-band-gap non-fullerene acceptors(NFAs)for high-performance organic solar cells(OSCs)remains challenging;the main constraint being the decrease in the energy level of the lowest unoccupied molecular orbitals(LUMOs)as the bandgap of A-D-A-type NFAs decrease.Therefore,the short current density(J_sc)and open-circuit voltage(V_oc)result in a trade-off relationship,making it difficult to obtain efficient OSCs.Herein,three NFAs(IFL-ED-4 F,IDT-ED-4 F,and IDTT-ED-2 F)were synthesized to address the above-mentioned issue by introducing 3,4-ethylenedioxythiophene(EDOT)as aπ-bridge.These NFAs exhibit relatively low bandgaps(1.67,1.42,and 1.49 eV,respectively)and upshifted LUMO levels(-3.88,-3.84,and-3.81 eV,respectively)compared with most reported low-band-gap NFAs.Consequently,the photovoltaic devices based on IDT-ED-4 F blended with a PBDB-T donor polymer showed the best power conversion efficiency(PCE)of 10.4%with a high J_sc of 22.1 mA cm^-2 and Voc of 0.884 V among the examined NFAs.In contrast,IDTT-ED-4 F,which was designed with an asymmetric structure of the D-p-A type,showed the lowest efficiency of 1.5%owing to the poor morphology and charge transport properties of the binary blend.However,when this was introduced as the third component of the PM6:BTP-BO-4 Cl,complementary absorption and cascade energy-level alignment between the two substances could be achieved.Surprisingly,the IDTT-ED-4 F-based ternary blend device not only improved the Jscand Voc,but also achieved a PCE of 15.2%,which is approximately 5.3%higher than that of the reference device with a minimized energy loss of 0.488 eV.In addition,the universality of IDTT-ED-2 F as a third component was effectively demonstrated in other photoactive systems,specifically,PM6:BTPe C9 and PTB7-Th:IEICO-4 F.This work facilitates a better understanding of the structure–property relationship for utilizing efficient EDOT-bridged NFAs in high-performance OSC applications.     

New emissive fac-tricarbonylchlorobis(ligand)rhenium(I) complexes prepared from pyridine/thiophene hybrid ligands

Stille coupling between tributyl-(2,3-dihydro-thieno[3,4-b][1,4]dioxin-5-yl)-stannane and 4-bromopyridine resulted in the preparation of the new pyridine/thiophene hybrid ligand 4-(2,3-dihydro-thieno[3,4-b][1,4]dioxin-5-yl)-pyridine [4-py-EDOT] (1). Reaction of 1, 4-thiophen-2-yl-pyridine (2), or 4-[2,2^′]bithiophenyl-5-yl-pyridine (3) with ClRe(CO)₅ resulted in the isolation of complexes 4-6, ClRe(L)₂(CO)₃, where L=1, 2, or 3 respectively. The solid-state structure of 4 was determined by X-ray crystallography, which clearly shows the fac arrangement of the three CO ligands and the two 4-py-EDOT ligands arranged cis to one another. The metal complexes 4-6 have been characterized by ¹H and ¹³C NMR, ESI or FAB MS, FTIR, UV-Vis, fluorescence, and elemental analysis.     

Efficient synthesis of 3,4-ethylenedioxythiophenes (EDOT) by Mitsunobu reaction

Using the Mitsunobu reaction as a key step, a general and efficient method for the synthesis of EDOT monomers has been developed. Novel substituted EDOTs and the first chiral derivatives were generated in high yields.     

One-step co-electrodeposition of graphene oxide doped poly(hydroxymethylated-3,4-ethylenedioxythiophene) film and its electrochemical studies of indole-3-acetic acid

A novel graphene oxide(GO) doped poly(hydroxymethylated-3,4-ethylenedioxythiophene)(PEDOTM)film has been achieved via one-step co-electrodeposition and utilized for electrochemical studies of indole-3-acetic acid(IAA).The incorporation of GO into PEDOTM film facilitated the electrocatalytic activity and exhibited a favorable interaction between the PEDOTM/GO film and the phytohormone during the oxidation of IAA.Under optimized conditions,differential pulse voltammetry and square wave voltammetry were used for the quantitative analysis of IAA,respectively,each exhibiting a wide linearity range from 0.6 μmol L~(-1) to 10 μmol L~(-1) and 0.05 μmol L~(-1) to 40 μmol L~(-1),good sensitivity with a low detection limit of 0.087 μmol L~(-1) and 0.033 μmol L~(-1) respectively,as well as good stability.With the notable advantages of a green,sensitive method,expeditious response and facile operation,the as-prepared PEDOTM/GO organic-inorganic composite film provides a promising platform for electrochemical studies of IAA.     

Tuning the band gap of easily oxidized bis(2-thienyl)– and bis(2-(3,4-ethylenedioxythiophene))–phenylene polymers

The synthesis, characterization and electrochemical polymerization, along with redox switching behavior of the resultant polymers, of 1,4-bis(2-(3,4-ethylenedioxy)thienyl)–2,5-difluorobenzene ( 1 ) and 1,4-bis(2-thienyl)–2,5-difluorobenzene ( 2 ) is presented. Compounds 1 and 2 were synthesized by a Pd°-catalyzed cross-coupling and in good yields (85% and 84%, respectively). Both monomers electropolymerize to form electroactive redox switchable films, with the more electron-rich 3,4-ethylenedioxythiophene derivative polymerizing and switching at lower potentials. The electronic band gaps were determined to be 1.9 eV for P1 and 2.3 eV for P2. Thin films of P1 and P2 were found to be electrochromic and exhibit color changes of red-to-blue/black for P1 and yellow-to-black for P2. These results are compared with various substituted bis(heterocycle)benzene derivatives in order to present a series of structure to property relationships. © 1998 John Wiley & Sons, Ltd.     

Rigid oligomers based on the combination of 3,6-dimethoxythieno[3,2-b]thiophene and 3,4-ethylenedioxythiophene

New oligomers based on the combination of the 3,6-dimethoxythieno[3,2-b]thiophene and 3,4-ethylenedioxythiophene (EDOT) moieties have been prepared and studied by UV-vis spectroscopy and cyclic voltammetry. The use of the intrinsically rigid thienothiophene units in addition to the S?O intramolecular interactions leads to planar conformation of the conjugated chains. While the radical cations of oligomers end capped by n-hexyl chains show a tendency to the dimerization, those substituted by n-hexylsulfanyl chains present a high stability.     

多色显示树枝状聚(3, 6-双噻吩咔唑)及其共聚物的电化学和电致变色性能

设计合成了一种新型的基于咔唑单元的树枝状3, 6-双噻吩咔唑衍生物(BTCPh),通过电化学聚合法制备出其均聚物及与3, 4-乙烯二氧噻吩(EDOT)的共聚物薄膜.利用电化学工作站-紫外可见光谱联用装置对两种聚合物的光谱电化学和电致变色(EC)性能进行表征.测试结果表明,均聚物(PBTCPh)薄膜在不同电压下可显示黄、绿、蓝、灰四种颜色;而EDOT单元的引入使共聚物P(BTCPh-EDOT)进一步增加了掺杂态,从而显示出更加丰富的五种颜色(橙、绿、棕绿、蓝、灰).此外,两种聚合物薄膜均具有良好的光学对比度和快速的响应速度,因而使其在智能窗及显示器方面展现了潜在的应用前景.     

The Simplest Model for Doped Poly(3,4-ethylenedioxythiophene) (PEDOT): Single-crystalline EDOT Dimer Radical Cation Salts

Although doped poly(3,4-ethylenedioxythiophene) (PEDOT) is extensively used in electronic devices, their molecular-weight distributions and inadequately defined structures have hindered the elucidation of their underlying conduction mechanism. In this study, we introduce the simplest discrete oligomer models: EDOT dimer radical cation salts. Single-crystal structural analyses revealed their one-dimensional (1D) columnar structures, in which the donors were uniformly stacked. Band calculations identified 1D metallic band structures with a strong intracolumnar orbital interaction (band width W≈1 eV), implying the origin of the high conductivity of doped PEDOT. Interestingly, the salts exhibited semiconducting behavior reminiscent of genuine Mott states as a result of electron–electron repulsion (U) dominant over W. This study realized basic models with tunable W and U to understand the conduction mechanism of doped PEDOT through structural modification in oligomers, including the conjugation length.     

Effect of hydroxypropyl-β-cyclodextrin on the electrochemical oxidation and polymerization of 3,4-ethylenedioxythiophene

The electrochemical oxidation of 3,4-ethylenedioxythiophene (EDOT) on platinum is studied in electrolyte solutions containing hydroxypropyl-β-cyclodextrin (HP-β-CD). HP-β-CD is found to increase the solubility of EDOT up to a concentration of 0.026 M in aqueous solutions. Addition of HP-β-CD (0.1 M) produces a slight red shift of the EDOT main absorption band from 254.9 to 257.7 nm and an increase of the HP-β-CD concentration decreases the absorption coefficient, _max to 6150 l mol⁻¹ cm⁻¹ in the UV–vis region, indicating complex formation. The cyclic voltammetric response of EDOT in 0.1 M aqueous LiClO₄ solutions consists of an ill-defined wave (P₁) and an adsorption peak (P₂). Contrary to the case of oxidation in acetonitrile medium, a post-peak is observed in the voltammograms of EDOT electro-oxidation in aqueous LiClO₄ solutions due to the adsorption of the oxidized EDOT species. A gradual reduction of the peak current of P₂ with increasing [HP-β-CD] and its total disappearance at high [HP-β-CD] suggest complex formation between HP-β-CD and EDOT√⁺ and also the peak P₂ to be due to adsorption of EDOT√⁺ species. The experiments intended to show the effect of ‘pre-adsorbed’ HP-β-CD on EDOT oxidation led to the conclusion that adsorbed HP-β-CD also solubilizes EDOT at the electrode surface. The CV behaviour of EDOT in HP-β-CD is discussed in comparison with that in sodium dodecylsulfate micellar solutions. Addition of increasing amounts of HP-β-CD shifts P₁ positively and P₂ negatively while also suppressing P₂ totally and reducing the peak current of P₁ to a significant extent. At a higher concentration of HP-β-CD, viz. 0.05 M, a peak appears at 1.29 V as a result of the above two opposing effects of CD on the peak potentials of P₁ and P₂. This resultant peak (P_composite) is more positive relative to the position of P₁ observed in the absence of HP-β-CD. The positive shift of the peak and peak current reduction indicate that EDOT (or an oxidized EDOT species) possibly interacts with the outer nucleophilic part of HP-β-CD. The electro-oxidation processes occurring at P₁ and P₂ are explained using an oligomeric approach, in which the electrochemical reactions are coupled to chemical reactions or adsorption of the oxidized species. Potential cycling of the platinum electrode in solutions containing 0.026 M EDOT+0.05 M HP-β-CD+0.1 M LiClO₄ between −0.5 and 1.2 V yields an adherent and smooth polymer film of poly(ethylenedioxythiophene), as shown in the SEM examination. In situ resistance measurements carried out with the polymer films in the electroactive region show a minimum resistance in the potential range of 0.3–0.4 V. Even the electrochemically-reduced films are found to possess some residual electrical conductivity.     

含3,4-乙撑二氧取代基的聚三噻吩衍生物的合成与表征

通过Stille反应合成了3,′4′-乙撑二-氧2,2′∶5,′2″-三噻吩,并以其作为单体,在0~5℃下,以FeCl3为氧化剂,在氯仿溶液中合成了3种聚(3,′4′-乙撑二氧-2,2′∶5,′2″-三噻吩)。并采用紫外-可见光谱(UV-Vis)、傅里叶红外光谱(FT-IR)、凝胶色谱(GPC)、循环伏安(CV)、透射电镜(TEM)和热重分析(TGA)对聚合物进行了表征。同时讨论了乙撑二氧取代基和FeCl3用量对聚合物性质的影响。结果表明:聚合物的紫外最大吸收为466~474 nm,数均分子量为3.4×103~3.6×103,能隙大约为2.05 eV,热分解温度为110℃。     

Design of organic semiconductors: tuning the electronic properties of pi-conjugated oligothiophenes with the 3,4-ethylenedioxythiophene (EDOT) building block

Hybrid oligothiophenes based on a various combinations of thiophene and 3,4-ethylenedioxythiophene (EDOT) groups have been synthesized. UV/Vis absorption spectra show that the number and relative positions of the EDOT groups considerably affect the width of the HOMO-LUMO gap and the rigidity of the conjugated system. Analysis of the crystallographic structure of two hybrid quaterthiophenes confirms that insertion of two adjacent EDOT units in the middle of the molecule leads to a self-rigidification of the conjugated systems by intramolecular SO interactions. Cyclic voltammetry data shows that the first oxidation potential of the oligomers decreases with increasing chain length and increasing number of EDOT groups for a given chain length. Electrochemical studies and theoretical calculations show that the positions of the EDOT units in the conjugated chain control the potential difference (DeltaE(p)) between the first and second oxidation steps. Moving the EDOT groups from the outer to the inner positions of the conjugated system increases DeltaE(p). Theoretical calculations confirm that this phenomenon reflects an increase of the intramolecular coulombic repulsion between positive charges in the dication. A thin-film field-effect transistor was fabricated by vacuum sublimation of a pentamer with alternating thiophene-EDOT structure, and the hole mobility was determined.     

烷氧磺酸盐功能化的聚乙撑二氧噻吩水凝胶

通过氧化偶联聚合方法成功地制备出一种基于烷氧磺酸盐功能化的聚乙撑二氧噻吩水凝胶, 揭示了零维单体胶束向二维纳米片层及三维水凝胶的转变过程, 发现通过改变反应温度或初始单体浓度, 可以诱导水凝胶网络结构单元的维度变化, 即由零维纳米粒子向二维纳米片层进行转化. 提出了一种导电高分子水凝胶的合成方法, 即采用一种氧化剂与一种多价金属盐的混合物作为引发剂, 其中前者用于诱导单体聚合, 后者则充当离子交联试剂, 并发现可以通过引入不同金属离子来改变凝胶的形貌. 此外, 导电高分子水凝胶具有良好的电化学电容, 并具有选择性吸附与可控脱附某些染料分子的特性.