Synthesis,chemical, and thermoelectric properties of n‐type π‐conjugated polymer composed of 1,2,4‐triazole and pyridine rings and its metal complexes

A soluble n‐type π‐conjugated polymer ( polymer 1 ) composed of a 1,2,4‐triazole ring substituted by a 4‐n‐octylphenyl subunit at the 4‐position of the 1,2,4‐triazole ring and pyridine‐2,5‐diyl rings was synthesized by Ni(cod)₂ (cod = 1,5‐cyclooctadiene) promoted dehalogenation polycondensation of 3,5‐bis(2‐bromopyridyl)‐4‐n‐octylphenyl‐1,2,4‐triazole ( monomer 1 ). A polymer complex ( polymer‐BiCl₃ ) was synthesized by the reaction of polymer 1 with BiCl₃. The UV–vis spectrum of polymer 1 exhibited an absorption maximum (λ_max value) at a longer wavelength than that exhibited by monomer 1 revealing that its π‐conjugation system was expanded along the polymer chain. Polymer 1 was electrochemically active in film, and the electrochemical reaction was accompanied with electrochromism. Thermoelectoric properties of polymer 1 and polymer‐BiCl₃ were investigated. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39928.     

Pd‐complex‐catalyzed synthesis of oligomers having a recurring benzodiazaborole unit in the main chain

BACKGROUND: Rigid‐rod oligomers and polymers comprising a recurring benzodiazaborole unit show high thermal stability and intriguing optical and electrochemical properties due to the expanded electron system through the B? C and B? N bonds in the main chain by the use of the p_z orbital on boron. However, the conventional method for the preparation of these oligomers and polymers often requires polycondensation under severe conditions. In this study, we report the synthesis of oligomers comprising a recurring benzodiazaborole unit using the Stille reaction under mild conditions. In addition, we describe their chemical properties and solid‐state structures. RESULTS: The reaction of 3,3′‐diaminobenzidine with 4‐bromophenylboronic acid and benzeneboronic acid yielded 2,2′‐bis(4‐bromophenyl)‐2,3,2′,3′‐tetrahydro‐1H,1′H‐[5,5′]bi(benzo[1,3,2]diazaborolyl) (1) and 2,2′‐biphenyl‐2,3,2′,3′‐tetrahydro‐1H,1′H‐[5,5′]bi(benzo[1,3,2]diazaborolyl), respectively. Pd‐complex‐catalyzed polycondensation of 1 with bis(tributyltin) and bis(tributylstannyl)acetylene in N,N‐dimethylformamide provided oligomers comprising a recurring benzodiazaborole unit in 98 and 97% yields, respectively. CONCLUSION: The oligomers comprising a recurring benzodiazaborole unit were obtained under mild reaction conditions in high yields. The expansion of the electron system through the B? C and B? N bonds of the oligomers was confirmed by UV‐visible spectroscopy. The oligomers were photoluminescent in solution and electrochemically active in a film, and they assumed self‐assembled stacked structures in the solid state. Copyright © 2008 Society of Chemical Industry     

Synthesis and Properties of Branched Oligo(2‐thienyl)‐ and Oligo(2,2′‐bithien‐5‐yl)‐Substituted Pyridine Derivatives

Starting from easily accessible precursors we describe the preparation of a series of branched oligo(2‐thienyl)‐ and oligo(2,2′‐bithienyl)‐substituted pyridine derivatives. With palladium‐catalyzed cross‐coupling reactions of pyridyl nonaflates/triflates as key steps we synthesized 2,6‐di(2‐thienyl)pyridines bridged by thiophene or benzene rings. By selective bromination of 2,6‐di(2‐thienyl)pyridine and 2,4,6‐tri(2‐thienyl)pyridine and subsequent coupling reactions an access to oligo(2,2′‐bithien‐5‐yl)‐substituted pyridine derivatives was gained. The constitution and solid state conformation of 2,6‐bis(2,2’‐bithien‐5‐yl)pyridine was determined by X‐ray analysis. This series of new pyridine‐thiophene conjugates was systematically investigated by UV/vis spectroscopy. Large Stokes shifts in the neutral and protonated form were observed. The electrochemical oxidation of two typical compounds was studied, however, these oxidations were irreversible forming a polymeric film at the anode. As a selected example, a thiophene‐bridged 2,6‐di(2‐thienyl)pyridine derivative was also investigated by scanning tunneling microscopy showing an interesting self‐assembly into a highly ordered monolayer on highly oriented pyrolytic graphite.

     

Palladium‐Catalyzed Direct Arylations of 1,2‐Azolo[1,5‐a]pyridines using Copper(I) Chloride as a Lewis Acid Activator and the Synthesis of 2,6‐Disubstituted Pyridines

A direct method for the arylation of 1,2‐azolo[1,5‐a]pyridines has been developed. In the process, the fused pyridines react with aryl halides in the presence of the palladium complex Pd(OAc)₂(Phen) as a catalyst and copper(I) chloride (CuCl) as a Lewis acid to form arylated derivatives. While pyrazolo[1,5‐a]pyridines and [1,2,4]triazolo[1,5‐a]pyridines are arylated at ortho‐positions of their pyridine rings using this method, in situ ring‐opening of the formed C‐7 arylated [1,5‐a]pyridine takes place to generate the 2,6‐disubstituted pyridine. Also, upon treatment with lithium diisopropylamide (LDA), C‐7 arylated pyrazolo[1,5‐a]pyridine‐3‐carboxylates react to produce diversely substituted 2,6‐disubstituted pyridines. Finally, a sequential C‐3 arylation was accomplished through a two‐step sequence involving hydrolysis of pyrazolo[1,5‐a]pyridine‐3‐carboxylates followed by the bimetallic Pd/Cu‐catalyzed decarboxylative coupling reaction with aryl bromide.

     

Synthesis and characterization of low‐molecular‐weight poly(2,6‐dimethyl‐1,4‐phenylene oxide) in water

Low‐molecular‐weight poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) with unimodal polydispersity was synthesized by oxidative polymerization of 2,6‐dimethylphenol in the presence of Cu‐ethylene diamine tetraacetic acid catalyst in water. A series of low‐molecular‐weight PPO oligomers with M_n ranged from 360 to 3500 were obtained. It was found that the molecular weight and polydispersity were affected by reaction time, reaction temperature, and catalyst concentration. Based on the detector response‐elution volume curve and the molecular weight from gel permeation chromatography, a possible molecular weight growth mechanism was proposed. The structure and properties of low‐molecular‐weight PPO oligomers were characterized by atomic absorption spectroscopy, differential scanning calorimetry, Ubbelohde viscometer, and nuclear magnetic resonance spectroscopy. Compared to the commercial low‐molecular‐weight PPO, PPO oligomers synthesized in water had a much lower residual copper content. The relationships between T_g and M_n at relatively low‐molecular weight are in good agreement with the equation proposed by Fox and Loshack. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Block copolyesters of poly(pentamethylene 2,6‐naphthalenedicarboxylate) and poly(tetramethylene adipate)

Hydroxy‐terminated poly(pentamethylene 2,6‐naphthalenedicarboxylate) oligomers were prepared by melt polycondensation of dimethyl 2,6‐naphthalenedicarboxylate with excess 1,5‐pentanediol followed by evacuating out some 1,5‐pentanediol. The molecular weight of the poly(pentamethylene 2,6‐naphthalenedicarboxylate) oligomers was controlled by the charge molar ratio of 1,5‐pentanediol to dimethyl 2,6‐naphthalenedicarboxylate and the amount of 1,5‐pentanediol removed under vacuum. The ¹H‐NMR spectra of the poly(pentamethylene 2,6‐naphthalenedicarboxylate) oligomers indicate that the transesterification between dimethyl 2,6‐naphthalenedicarboxylate and 1,5‐pentanediol was almost complete. Block copolyesters with hard segments of poly(pentamethylene 2,6‐naphthalenedicarboxylate) and soft segments of poly(tetramethylene adipate) were prepared by coupling the poly(pentamethylene 2,6‐naphthalenedicarboxylate) oligomer and a poly(tetramethylene adipate) glycol with methylene‐4,4′‐diphenylene diisocyanate in solution. The block copolyesters were characterized by IR, ¹H‐NMR, DSC, and X‐ray diffraction. The hard segments in the block copolyesters display an amorphous state. However, the thermal transitions of soft segments in the block copolyesters are strongly dependent on the composition. When the content of the hard segments increases, the glass transition temperature of the soft segments increases. Thus, the amorphous parts of the soft segments would be partially miscible with the hard segments. When the content of the hard segments is very low, the soft segments of the block copolyesters exhibit high crystallinity. But, as the content of the hard segments is about 30 wt % or more, the soft segments of the block copolyesters become amorphous. This is described as the effect of the presence of the hard segments which are partially miscible with the soft segments. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3652–3659, 2002     

Organosoluble,low‐dielectric‐constant fluorinated polyimides based on 2,6‐bis(4‐amino‐2‐trifluoromethylphenoxy)naphthalene

A novel fluorinated bis(ether amine) monomer, 2,6‐bis(4‐amino‐2‐trifluoromethylphenoxy) naphthalene, was prepared through the nucleophilic aromatic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and 2,6‐dihydroxynaphthalene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of novel trifluoromethylated polyimides were synthesized from the diamine with various commercially available aromatic tetracarboxylic dianhydrides using a two‐stage process with thermal imidization of poly(amic acid) films. Most of the resulting polyimides were highly soluble in a variety of organic solvents and could afford transparent and tough films via solution casting. These polyimides exhibited moderately high glass transition temperatures (T_gs) of 249–311 °C, high thermal stability and good mechanical properties. Low moisture (0.19–0.85 %), low dielectric constants (2.49–3.59 at 10 kHz), and low color intensity were also observed. For a comparative study, a series of analogous polyimides based on 2,6‐bis(4‐aminophenoxy)naphthalene were also prepared and characterized. Copyright © 2005 Society of Chemical Industry     

Iridium‐Catalyzed Asymmetric Allylic Etherification and Ring‐Closing Metathesis Reaction for Enantioselective Synthesis of Chromene and 2,5‐Dihydrobenzo[b]oxepine Derivatives

Iridium‐catalyzed asymmetric etherifications of allylic carbonates with 2‐vinylphenols and 2‐allylphenols were realized. With a catalyst generated from 2 mol% of [Ir(cod)Cl]₂ (cod=cycloocta‐1,5‐diene) and 4 mol% of the phosphoramidite ligand L2 , the etherification products were obtained in excellent ees and then subjected to the ring‐closing metathesis reaction providing an efficient synthesis of enantioenriched 2H‐chromene and 2,5‐dihydrobenzo[b]oxepine derivatives.     

Unexpected Reaction of 2,2′‐Bipyridyl‐cycloocta‐1,5‐diene‐nickel(0) with Acetone and Dioxygen

The reaction of (bipy)Ni(cod) ( 1 ) (bipy = 2,2′‐bipyridyl, cod = cycloocta‐1,5‐diene) with dioxygen and acetone at −20°C affords (bipy)Ni(C₉H₁₆O₃) ( 2 ) (C₉H₁₆O₃^2— = 2,4,6,6‐tetramethyl‐tetrahydropyran‐2,4‐diolate), which has been characterized by NMR, MS and an X‐ray crystal structure determination. Acidolysis of compound 2 with two equivalents of acetyl acetone (Hacac) yields (bipy)Ni(acac)₂ and C₉H₁₈O₃ ( 3 ) (2,4,6,6‐tetramethyl‐tetrahydropyran‐2,4‐diol), a cyclic trimer of acetone.     

A redox‐mediator‐doped gel polymer electrolyte applied in quasi‐solid‐state supercapacitors

Methylene blue (MB) redox mediator was introduced into polyvinyl alcohol/polyvinyl pyrrolidone (PVA/PVP) blend host to prepare a gel polymer electrolyte (PVA‐PVP‐H₂SO₄‐MB) for a quasi‐solid‐state supercapacitor. The electrochemical properties of the supercapacitor with the prepared gel polymer electrolyte were evaluated by cyclic voltammetry, galvanostatic charge–discharge, electrochemical impedance spectroscopy, and self‐discharge measurements. With the addition of MB mediator, the ionic conductivity of gel polymer electrolyte increased by 56% up to 36.3 mS·cm^?1, and the series resistance reduced, because of the more efficient ionic conduction and higher charge transfer rate, respectively. The electrode specific capacitance of the supercapacitor with PVA‐PVP‐H₂SO₄‐MB electrolyte is 328 F·g^?1, increasing by 164% compared to that of MB‐undoped system at the same current density of 1 A·g^?1. Meanwhile, the energy density of the supercapacitor increases from 3.2 to 10.3 Wh·kg^?1. The quasi‐solid‐state supercapacitor showed excellent cyclability over 2000 charge/discharge cycles. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39784.     

Electrochromic properties of a copolymer of 1‐4‐di[2,5‐di(2‐thienyl)‐1H‐1‐pyrrolyl]benzene with EDOT

Homopolymer of 1‐4‐di[2,5‐di(2‐thienyl)‐1H‐1‐pyrrolyl]benzene and its copolymer with 3,4‐ethylenedioxythiophene (EDOT) were electrochemically synthesized and characterized. Resulting homopolymer and copolymer films have distinct electrochromic properties. At the neutral state, homopolymer has λ_max due to the π‐π* transition as 410 nm and E_g was calculated as 2.03 eV. The resultant copolymer revealed multichromism through the entire visible region, displaying red‐violet, brownish yellow green, and blue colors with the variation of the applied potential. For the copolymer, λ_max and E_g were found to be 450 nm and 1.66 eV, respectively. Double potential step chronoamperometry experiment shows that homopolymer and copolymer films have good stability, fast switching times, and high optical contrast in NIR region as 41 and 30%, respectively. Copolymerization with EDOT not only decreases the band gap, E_g, but also enhances the electrochromic properties. Hence, electrochemical copolymerization is considered to be a powerful tool to improve the electrochromic properties of N‐substituted 2,5‐di(2‐thienylpyrrole) derivatives. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis,Crystal Structure,and Thermal Behaviors of 3‐Nitro‐1,5‐bis(4,4′‐dimethylazide)‐1,2,3‐triazolyl‐3‐azapentane (NDTAP)

The energetic material, 3‐nitro‐1,5‐bis(4,4′‐dimethyl azide)‐1,2,3‐triazolyl‐3‐azapentane (NDTAP), was firstly synthesized by means of Click Chemistry using 1,5‐diazido‐3‐nitrazapentane as main material. The structure of NDTAP was confirmed by IR, ¹H NMR, and ¹³C NMR spectroscopy; mass spectrometry, and elemental analysis. The crystal structure of NDTAP was determined by X‐ray diffraction. It belongs to monoclinic system, space group C2/c with crystal parameters a=1.7285(8) nm, b=0.6061(3) nm, c=1.6712(8) nm, β=104.846(8)°, V=1.6924(13) nm³, Z=8, μ=0.109 mm⁻¹, F(000)=752, and D_c=1.422 g cm⁻³. The thermal behavior and non‐isothermal decomposition kinetics of NDTAP were studied with DSC and TG‐DTG methods. The self‐accelerating decomposition temperature and critical temperature of thermal explosion are 195.5 and 208.2 °C, respectively. NDTAP presents good thermal stability and is insensitive.     

Synthesis and characterization of novel soluble pyridine‐containing polyimides based on 4‐phenyl‐2,6‐bis[4‐(4‐aminophenoxy)phenyl]‐pyridine and various aromatic dianhydrides

A new kind of pyridine‐containing aromatic diamine monomer, 4‐phenyl‐2,6‐bis[4‐(4‐aminophenoxy)phenyl]‐pyridine (PAPP), was successfully synthesized by a modified chichibabin reaction of benzaldehyde and a substituted acetophenone, 4‐(4‐nitrophenoxy)‐acetophenone (NPAP), followed by a reduction of the resulting dinitro compound 4‐phenyl‐2,6‐bis[4‐(4‐nitrophenoxy)phenyl]‐pyridine (PNPP) with Pd/C and hydrazine monohydrate. The aromatic diamine was employed to synthesize a series of new pyridine‐containing polyimides by polycondensation with various aromatic dianhydrides in N‐methy‐2‐pyrrolidone (NMP) via the conventional two‐step method, i.e., ring‐opening polycondensation forming the poly (amic acid)s and further thermal or chemical imidization forming polyimides. The inherent viscosities of the resulting polyimides were in the range of 0.79–1.13 dL/g, and most of them were soluble in common organic solvents such as N,N‐dimethylacetamide (DMAc), NMP, and tetrahydrofuran (THF), etc. Meanwhile, strong and flexible polyimide films were obtained, which had good thermal stability, with the glass transition temperatures (T_g) of 268–338°C and the temperature at 5% weight loss of 521–548°C in air atmosphere, as well as outstanding mechanical properties with tensile strengths of 89.2–112.1 MPa and elongations at break of 9.5–15.4%. The polyimides also were found to possess low dielectric constants ranging from 2.53 to 3.11. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 212–219, 2007     

Synthesis and characterization of N‐methyl‐2,6‐dinitrodiphenylamine‐4‐diazonium salt and its diazoresin

A new photosensitive agent, dinitro derivatives of diphenylamine diazonium salt (N‐methyl‐2,6‐dinitrodiphenylamine‐4‐diazonium salt, MDNDDS), and its diazoresin were synthesized. Their photoreactivities and thermostabilities were investigated. Our results revealed that MDNDDS and MDNDDS‐resin exhibited greatly improved thermostability both in solid state and in coating film comparing with the conventional unsubstituted and mononitro substituted diphenylamine diazonium salts (DDS and MNDDS, respectively) and their diazoresins. The photosensitivity of MDNDDS was found to be slightly lower than DDS but still comparable with MNDDS. As a result of its improved thermostability, both MDNDDS‐resin as a photosensitive agent and lithographic printing plate prepared by MDNDDS‐resin will have a long shelf‐life, which is very important to reduce waste and factory running‐cost. MDNDDS also has a maximum absorption wavelength (λ_max) at 425 nm, which means that an iodine gallium lamp (main emission wavelength λ_em = 420 nm), is better than conventional mercury lamp (λ_em = 360 nm), to be used as the irradiation source in the photoimaging process. Compared with the mercury lamp, iodine gallium lamp is cheaper and greener. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and spectroelectrochemistry of dithieno(3,2‐b:2′,3′‐d)pyrrole derivatives

New π‐conjugated polymers containing dithieno(3,2‐b:2′,3′‐d)pyrrole (DTP) were successfully synthesized via electropolymerization. The effect of structural differences on the electrochemical and optoelectronic properties of the 4‐[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl]aniline (DTP–aryl–NH₂), 10‐[4H‐dithiyeno(3,2‐b:2′,3′‐d)pirol‐4‐il]dekan‐1‐amine (DTP–alkyl–NH₂), and 1,10‐bis[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl] decane (DTP–alkyl–DTP) were investigated. The corresponding polymers were characterized by cyclic voltammetry, NMR (¹H‐NMR and ¹³C‐NMR), and ultraviolet–visible spectroscopy. Changes in the electronic nature of the functional groups led to variations in the electrochemical properties of the π‐conjugated systems. The electroactive polymer films revealed redox couples and exhibited electrochromic behavior. The replacement of the DTP–alkyl–DTP unit with DTP–aryl–NH₂ and DTP–alkyl–NH₂ resulted in a lower oxidation potential. Both the poly(10‐(4H‐Dithiyeno[3,2‐b:2′,3′‐d]pirol‐4‐il)dekan‐1‐amin) (poly(DTP–alkyl–NH₂)) and poly(1,10‐bis(4H‐dithieno[3,2‐b:2′,3′‐d]pyrrol‐4‐yl) decane) (poly(DTP–alkyl–DTP)) films showed multicolor electrochromism and also fast switching times (<1 s) in the visible and near infrared regions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40701.     

Synthesis of poly(1‐hexene)s end‐functionalized with phenols

Electrophilic alkylations of phenol/2,6‐dimethylphenol were performed with vinylidene‐terminated poly(1‐hexene)s using BF₃·OEt₂ catalyst. Vinylidene‐terminated poly(1‐hexene)s with M_n varying from 400 to 10000 were prepared by bulk polymerization of 1‐hexene at 50 to ?20 °C using Cp₂ZrCl₂/MAO catalysts. The phenol/2,6‐dimethylphenol‐terminated poly(1‐hexene)s was characterized by NMR (¹H, ¹³C), UV, IR and vapor phase osmometer (VPO). The isomer distribution (ortho, para and ortho/para) was determined by ¹³P NMR using a phosphitylating reagent, namely 2‐chloro‐1,3,2‐dioxaphospholane. The number‐average degree of functionality (F_n) >0.9 with >95% para selectivity could be achieved using low‐molecular‐weight oligomers of poly(1‐hexene)s. Copyright © 2005 Society of Chemical Industry     

Preparation and photocurrent generation of an electrostatically self‐assembled film of hemicyanine and poly(4‐styrenesulfonic acid‐co‐maleic acid)

In this article, we report on electrostatically self‐assembled thin films prepared by the alternative immersion of quartz‐coated and indium tin oxide coated glass substrates in aqueous solutions of a copolymer of poly(4‐styrenesulfonic acid‐co‐maleic acid) (PSSMA) and a hemicyanine of (E)?1,1′‐(propane‐1,3‐diyl)bis{4‐[4‐(dimethylamino)styryl]pyridinium} bromide (H³Br₂). The films were studied by means of ultraviolet–visible absorption and X‐ray photoelectron spectroscopies, scanning electron microscopy, and photoelectrochemical measurements. When irradiated with white light, the PSSMA/H³ monolayer film gave a stable cathodic photocurrent. The effects of the applied bias voltages, layer numbers of the (PSSMA/H³)_n films (where n stands for the number of bilayer films on both sides of the substrates), light intensities, pH value, and electron acceptor on the photocurrent generation of the (PSSMA/H³)_n film were examined. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39871.     

Synthesis and properties of polymer from bis‐3,4‐ethylenedioxythiophene substituted acenaphthenequinoxaline

A new electrochoromic polymer poly(8,11‐bis(3,4‐ethylenedioxy thiophen‐2‐yl)acenaphtho[1,2‐b]‐quinoxaline) (PBEAQ) was synthesized by electrochemical polymerization of the corresponding monomer (BEAQ) in a 0.1 M tetraethylammonium tetrafluoroborate (TEABF₄) dichloromethane–acetonitrile (2 : 1, v : v) solution. The monomer and polymer were characterized by elemental analysis, ¹H‐NMR, IR, and UV‐vis spectroscopy. The electrochemical and optical properties of polymer were investigated by cyclic voltammetry and UV‐vis spectroscopy. Cyclic voltammetry and spectroelectrochemistry studies demonstrated that the polymer can be reversibly reduced and oxidized (both n‐ and p‐doped) between ?2 V and +1.5 V vs. Ag/Ag⁺. The polymer had a transmissive light blue color in the oxidized state and reddish color in the reduced state. Undoped polymer shows UV‐vis absorption peaks at 615 nm in solution, 650 nm in solid state, and has an optical band gap of 1.5 eV. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Gold(I)‐Catalyzed Tandem Alkoxylation/Lactonization of γ‐Hydroxy‐α,β‐Acetylenic Esters

The formation of 4‐alkoxy‐2(5H)‐furanones was achieved via tandem alkoxylation/lactonization of γ‐hydroxy‐α,β‐acetylenic esters catalyzed by 2 mol% of [2,6‐bis(diisopropylphenyl)imidazol‐2‐ylidine]gold bis(trifluoromethanesulfonyl)imidate [Au(IPr)(NTf₂)]. The economic and simple procedure was applied to a series of various secondary propargylic alcohols allowing for yields of desired product of up to 95%. In addition, tertiary propargylic alcohols bearing mostly cyclic substituents were converted into the corresponding spiro derivatives. Both primary and secondary alcohols reacted with propargylic alcohols at moderate temperatures (65–80 °C) in either neat reactions or using 1,2‐dichloroethane as a reaction medium allowing for yields of 23–95%. In contrast to [Au(IPr)(NTf₂)], reactions with cationic complexes such as [2,6‐bis(diisopropylphenyl)imidazol‐2‐ylidine](acetonitrile)gold tetrafluoroborate [Au(IPr)(CH₃CN)][BF₄] or (μ‐hydroxy)bis{[2,6‐bis(diisopropylphenyl)imidazol‐2‐ylidine]gold} tetrafluoroborate or bis(trifluoromethanesulfonyl)imidate – [{Au(IPr)}₂(μ‐OH)][X] (X=BF₄, NTf₂) – mostly stop after the alkoxylation. Analysis of the intermediate proved the exclusive formation of the E‐isomer which allows for the subsequent lactonization.     

Poly(2,6‐di(thiophene‐2‐yl)‐3,5bis(4‐(thiophene‐2‐yl)phenyl)dithieno [3,2‐b;2',3'‐d]thiophene)/carbon nanotube composite for capacitor applications

A novel monomer, 2,6‐di(thiophene‐2‐yl)‐3,5bis(4‐(thiophene‐2‐yl)phenyl)dithieno[3,2‐b;2',3'‐d]thiophene ( Th₄DTT) has been synthesized and used as an electro‐active material. It has been electropolymerized onto glassy carbon (GC) electrode in sodium dodecyl sulfate (SDS) solution (0.1 M) together with multi‐walled carbon nanotubes (MWCNT). A good capacitive characteristics for P(Th₄DTT)/MWCNT composite has been obtained by electrochemical impedance spectroscopy (EIS), which is, to our best knowledge, the first report on capacitor behavior of a dithienothiophene. A synergistic effect has been resolved by Nyquist, Bode‐magnitude—phase and admittance plots. Specific capacitance of the conducting polymer/MWCNT, calculated from cyclic voltammogram (CV) together with area and charge formulas, has been found to be 20.17 F g^?1. Long‐term stability of the capacitor has also been tested by CV, and the results indicated that, after 500 cycles, the specific capacitance is 87.37% of the initial capacitance. An equivalent circuit model of R_s(C₁(R₁(Q(R₂W))))(C₂R₃) has been obtained to fit the experimental and theoretical data. The double layer capacitance (C_dl) value of P(Th₄DTT)/MWCNT (4.43 mF cm^?2) has been found to be 25 times higher than P(Th₄DTT) (C_dl= 0.18 mF cm^?2). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40061.