Study of electrochemical stability of conducting polymers by bidimensional spectroelectrochemistry: p- and n-doping of poly(4,4′-bis(butylthio)-2,2′-bithiophene) films

UV-vis bidimensional spectroelectrochemistry has been applied to the study of the electrochemical stability of conducting polymer films during p- and n-doping processes. Specifically, poly(4,4′-bis(butylthio)-2,2′-bithiophene) has been chosen as example to prove the usefulness and suitability of this multi-response technique to characterize polymer stability during p- and n-doping. It was found that oxidative doping and corresponding de-doping alone did not result in noticeable polymer film degradation. However, in experiments involving both p- and n-doping of this conducting polymer, soluble species arising from the polymer film were detected in solution for the first time, indicating a lower electrochemical stability of the film under these experimental conditions. Moreover, bidimensional spectroelectrochemistry has enabled us not only to detect the soluble degradation products, but also the potential range in which the degradation takes place.     

Poly(3,3′-dimethoxy-2,2′-bithiophene): Synthesis and comparison with poly(3-methoxythiophene)

A new electroactive polymer, namely poly(3,3′-dimethoxy-2,2′-bithiophene) has been prepared by voltammetric polymerization of 3,3′-dimethoxy-2,2′-bithiophene. Due to a different coupling pattern (equivalent to “head-to-head,” and “tail-to-tail” coupled alkoxythiophene rings), poly(3,3′-dimethoxy-2,2′-bithiophene) exhibits different voltammetric properties than the corresponding “head-to-tail” coupled polymer, i.e., poly(3-methoxythiophene). Poly(3,3′-dimethoxy-2,2′-bithiophene) gives very sharp oxidation and reduction peaks indicating an abrupt insulator to conductor transition. This hypothesis was corroborated by the studies of relative resistance as a function of electrode potential. Sharper and better-defined redox peaks may indicate better stereoregularity of poly(3,3′-dimethoxy-2,2′-bithiophene) as compared to poly(3-methoxythiophene) since in this compound the 5,5′-coupling positions are geometrically equivalent and no coupling defects are expected. © 1992 John Wiley & Sons, Inc.     

Preparation and properties of aromatic polyamides from 2,2′-bis(p-carboxyphenoxy) biphenyl or 2,2′-bis(p-carboxyphenoxy)-1,1′-binaphthyl and aromatic diamines

New aromatic dicarboxylic acids having kink and crank structures, 2,2′-bis(p-carboxyphenoxy) biphenyl and 2,2′-bis(p-carboxyphenoxy)-1,1′-binaphthyl, were synthesized by the reaction of p-fluorobenzonitrile with biphenyl-2,2′-diol and 2,2′-dihydroxy-1,1′-binaphthyl, respectively, followed by hydrolysis. Biphenyl-2,2′-diyl-and 1,1′-binaphthyl-2,2′-diyl-containing aromatic polyamides having inherent viscosities of 0.58–1.46 dL/g and 0.63–1.30 dL/g, respectively, were obtained by the low-temperature solution polycondensation of the corresponding diacid chlorides with aromatic diamines. These polymers were readily soluble in a variety of organic solvents including N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide, m-cresol, and pyridine. Transparent, pale yellow, and flexible films of these polymers could be cast from the DMAc or NMP solutions. These aromatic polyamides containing biphenyl and binaphthyl units had glass transition temperatures in the range of 210–272 and 260–315°C, respectively. They began to lose weight around 380°C, with 10% weight loss being recorded at about 450°C in air. © 1993 John Wiley & Sons, Inc.     

Synthesis and characterization of new soluble polyamides derived from 3,3′,5,5′-tetramethyl-2,2-bis[4-(4-carboxyphenoxy)phenyl]propane

A series of new soluble polyamides having isopropylidene and methyl-substituted arylene ether moieties in the polymer chain were prepared by the direct polycondensation of 3,3′,5,5′-tetramethyl-2,2-bis[4-(4-carboxyphenoxy)phenyl]propane and various diamines in N-methyl-2-pyrrolidinone (NMP) containing CaCl₂ using triphenyl phosphite and pyridine as condensing agents. Polymers were produced with moderate to high inherent viscosities of 0.85–1.47 dL g⁻¹ while the weight-average molecular weight and number-average molecular weight were in the range of 86,700–259,000 and 43,300–119,000, respectively. All the polymers were readily dissolved in polar aprotic solvents such as NMP, N,N-dimethylacetamide, and N,N-dimethylformamide, as well as less polar solvents such as m-cresol and pyridine, and even soluble in tetrahydrofuran. These polymers were solution-cast into transparent, flexible and tough films. All of the polymers were amorphous and the polyamide films had a tensile strength range of 82–122 MPa, an elongation at break range of 6–18%, and a tensile modulus range of 2.0–2.8 GPa. These polyamides had glass transition temperatures between 233–260°C and 10% weight loss temperatures in the range of 450–489 and 459–493°C in nitrogen and air atmosphere, respectively. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1997–2003, 1999     

Differential Pulse Techniques on Modified Conventional‐Size and Microelectrodes. Electroactivity of Poly[4,4′‐bis(butylsulfanyl)‐2,2′‐bithiophene] Coating Towards Dopamine and Ascorbic Acid Oxidation

Poly[4,4′‐bis(butylsulfanyl)‐2,2′‐bithiophene] modified conventional‐size and (ultra)microelectrodes are first investigated in acetonitrile and quasi‐neutral aqueous solution with respect to the repeatability of the responses obtained both in cyclic voltammetry and in differential pulse voltammetry. The reactivity towards ferrocene and hydroquinone, chosen as benchmark oxidizable substances in the two media, respectively, is considered. Comparison is made with the behavior of poly(3‐methylthiophene) as electrode coating, which is one of the most commonly used redox mediators in amperometric sensors based on coatings consisting of conducting polymers. The results confirm the appealing properties of poly[4,4′‐bis(butylsulfanyl)‐2,2′‐bithiophene], previously evidenced by us in different electrochemical studies: it exhibits particularly high stability and the characteristics of the current/potential curves obtained make it particularly suitable for analytical purposes. After performing these tests, the quantitative determination of dopamine by modified microelectrode is examined and the simultaneous voltammetric determination of ascorbic acid and dopamine is considered. The possibility of working profitably with a microelectrode at very low buffer‐supporting electrolyte concentration is ascertained.     

Preparation and properties of aromatic polyamides from 2,2′-bis(p-aminophenoxy) biphenyl or 2,2′-bis(p-aminophenoxy)-1,1′-binaphthyl and aromatic dicarboxylic acids

New aromatic diamines having kink and crank structures, 2,2′-bis(p-aminophenoxy)biphenyl and 2,2′-bis(p-aminophenoxy)-1,1′-binaphthyl, were synthesized by the reaction of p-fluoronitrobenzene with biphenyl-2,2′-diol and 2,2′-dihydroxy-1,1′-binaphthyl, respectively, followed by catalytic reduction. Biphenyl-2,2′-diyl- and 1,1′-binaphthyl-2,2′-diyl-containing aromatic polyamides having inherent viscosities of 0.44–1.18 and 0.26–0.88 dL/g, respectively, were obtained either by the direct polycondensation or low-temperature solution polycondensation of the diamines with aromatic dicarboxylic acids (or diacid chlorides). These polymers were readily soluble in a variety of organic solvents including N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide, m-cresol, and pyridine. Transparent, pale yellow, and flexible films of these polymers could be cast from the DMAc or NMP solutions. These aromatic polyamides containing biphenyl and binaphthyl units had glass transition temperatures in the range of 215–255 and 266–303°C, respectively. They began to lose weight at ca. 380°C, with 10% weight loss being recorded at about 470°C in air. © 1993 John Wiley & Sons, Inc.     

Preparation and properties of aromatic polyimides from 2,2′-bis(p-aminophenoxy)biphenyl or 2,2′-bis)p-aminophenoxy)-1,1′-binaphthyl and aromatic tetracarboxylic dianhydrides

New aromatic polyimides containing a biphenyl-2,2′-diyl or 1,1′-binaphthyl-2,2′-diyl unit were prepared by a conventional two-step method starting from 2,2′-bis(p-aminophenoxy) biphenyl or 2,2′-bis(p-aminophenoxy)-1,1′-binaphthyl and aromatic tetracarboxylic dianhydrides. The polyimides having inherent viscosities of 0.69–0.99 and 0.51–0.59 dL/g, respectively, were obtained. Some of these polymers were readily soluble in a variety of organic solvents including N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide, and pyridine. Transparent, flexible, and pale yellow to brown films of these polymers could be cast from the DMAc or NMP polyamic acid solutions. These aromatic polyimides containing biphenyl and binaphthyl units had glass transition temperatures in the range of 200–235 and 286–358°C, respectively. They began to lose weight around 380°C, with 10% weight loss being recorded at about 470°C in air. © 1993 John Wiley & Sons, Inc.     

Synthesis and characterization of poly[2,5-bis(triethoxy)-1,4-phenylene vinylene]

The synthesis of a highly soluble, 2,5-disubstituted poly(p-phenylene vinylene) with pendant side chains containing ether groups was accomplished by a dehydrochlorination route. Specific interactions of the oxygen-containing side chains with the solvent are presumably responsible for the high solubility of the polymer, especially in protogenic solvents. The polymer microstructure was characterized by ¹H- and ¹³C-NMR. The polymer showed solvatochromic properties when dissolved in a variety of solvents. The relatively high molecular weight (M_n = 17,000) permitted the fabrication of free-standing films. The electrical conductivity of iodine-doped films was approximately 2 × 10^–2 S cm^–1. © 1995 John Wiley & Sons, Inc.     

4,4'-二(对氨基苯乙炔基)-6,6'-二[N,N-二(乙氧基羰甲基)氨甲基]-2,2'-联吡啶的合成与表征

以4,4'-二硝基-2,2'-联吡啶-6,6'-二亚甲基双三氟乙酸酯作为起始原料, 经水解、 溴化、 酯化和对氨基苯乙炔取代4步反应合成了4,4'-二(对氨基苯乙炔基)-6,6'-二[N,N-二(乙氧基羰甲基)氨甲基]-2,2'-联吡啶. 通过红外光谱、 核磁共振波谱、 高分辨质谱等表征了该化合物的结构. 该化合物经水解后与铕离子形成稀土荧光螯合物, 在紫外光激发下, 发射出具有铕离子特征的荧光光谱.     

Synthesis and Crystal Structure of 4,4'-(4-(1-Naphthyl)-4-phenyl-1,3-butadienylidene)-bis[N,N-diethylbenzenamine]

1 INTRODUCTION Organic photo-conductors (OPCs), due to their great advantages over inorganic ones, have been widely used in xerography and holography and aroused considerable interest in the past several de- cades. Recently, almost all OPCs are of a layered structure with a thin charge generation layer (CGL) and a charge transport layer (CTL). Current resear- ches are directed to both improving the chara- cteristics of existing OPCs and developing new ma- terials for future applicati…     

聚丙烯酸[2,5-双(对甲氧基苯甲酰氧基)苄酯]及聚甲基丙烯酸[2,5-双(对甲氧基苯甲酰氧基)苄酯]的合成

周其凤等曾报道聚丙烯酸［２,５－双（对甲氧基苯甲酰氧基）节酯］［１］和聚甲基丙烯酸［２,５－双（对甲氧基苯甲酰氧基）苄酯］［２］的合成．但后来的研究发现,在合成单体的条件下出现的一种未见报道的异常反应［３］使产物成分复杂化,因此当时报道的聚合物可能不是聚丙烯酸［２,５－双－（对甲氧基苯甲酰氧基）苄酯］或聚甲基丙烯酸［２,５－双（对甲氧基苯甲酰氧基）苄酯］,而可能是共聚物．针对这一问题,我们重新设计了合成路线以避免发生上述副反应,成功地合成了丙烯酸或ａ－甲基丙烯酸［２,５－双－（对甲氧基苯甲酰氧基…     

Synthesis and properties of soluble aromatic polyimides from 2,2′-bis(3,4-dicarboxyphenoxy)-1,1′-binaphthyl dianhydride and aromatic diamines

Aromatic tetracarboxylic dianhydride having crank and twisted noncoplanar structure, 2,2′-bis(3,4-dicarboxyphenoxy)-1,1′-binaphthyl dianhydride, was synthesized by the reaction of 4-nitrophthalonitrile with 2,2′-dihydroxy-1,1′-binaphthyl, followed by alkaline hydrolysis of the intermediate bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). Binaphthyl-2,2′-diyl–containing novel aromatic polyimides having inherent viscosities up to 0.67 dL/g were obtained by the one-step polymerization process starting from the bis(ether anhydride) and various aromatic diamines. All the polyimides showed typical amorphous diffraction patterns. Most of the polyimides were readily soluble in common organic solvents such as N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), and pyridine. These aromatic polyimides had glass transition temperatures in the range of 280–350°C, depending on the nature of the diamine moiety. All polymers were stable up to 400°C, with 10% weight loss being recorded above 485°C in air. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1937–1943, 1998     

Synthesis and characterization of novel polyaryloxydiphenylsilane derived from 2,2′- dimethyl-biphenyl-4,4′-diol

A novel polyaryloxydiphenylsilane was synthesized successfully by solution polycondensation of 2,2′-dimethyl-biphenyl-4,4′-diol with diphenyldichlorosilane and the catalyst triethylamine in toluene at 80 °C. Polymers with a relatively high inherent viscosity and yield were obtained when the reactions were carried out in aromatic and lipophilic solvents. The novel polyaryloxydiphenylsilane was soluble in chlorinated aliphatic hydrocarbons such as methylene chloride and chloroform as well as in polar solvents such as dimethyl sulfoxide, N,N-dimethylformamide, and N,N-dimethylacetamide and also in some common organic solvents such as benzene and toluene. However, it was insoluble in both aliphatic hydrocarbons as well as in alcoholic solvents. The polyaryloxydiphenylsilane began losing weight around 400 °C under a nitrogen atmosphere, and the 10% weight-loss temperature was 473 °C. The glass-transition temperature of the polyaryloxydiphenylsilane was 102 °C. The glass transition could be lowered by the copolymerization technique with 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane as an aromatic diol comonomer. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4591–4595, 1999     

Preparation and characterization of colorless alternate poly(amide-imide)s based on trimellitic anhydride and 2,2-bis[4-(3-aminophenoxy)phenyl]sulfone

Alternate poly(amide-imide) [P(A-alt-I)] was synthesized from two aromatic diamines and trimellitic anhydride (TMA). When the diamine was 2,2-bis[4-(3-aminophenoxy)phenyl]sulfone (BAPS), the resulted P(A-alt-I) was found to be of light color. Specifically, when BAPS was located between two amide groups in the P(A-alt-I) chain, the P(A-alt-I) was almost colorless. A series of P(A-alt-I)s (Series III) containing BAPS was synthesized through direct polycondensation of an aromatic dicarboxylic acid prepared from various aromatic diamines and TMA, as well as BAPS. Polymers of Series III were much lighter in color than those of the isomeric series (BAPS was located between two imide group). The series of P(A-alt-I)s III had inherent viscosities ranging 0.69–1.35 dL/g and good solubility in various solvents. The tensile strengths, elongations to break, and initial moduli of the films were 72–107 MPa, 7–12% and 1.93–2.39 GPa, respectively, and most of the films had no yielding. Polymers of Series III had glass transition temperatures 210–272°C and 10% weight loss temperatures in nitrogen 518–545°C, indicating excellent thermal stability. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2421–2428, 1999     

消旋的有机二磺酸三邻菲咯啉锌配合物(英)

Compound [Zn(phen)₃][BDA] (1) (BDA=6,6′-dibromo-2,2′-dimethoxy-1,1′-binaphthylene-4,4′-disulfonate, phen= 1,10-phenanthroline) composes of the anion part (racemic-(R,S)-6,6′-dibromo-2,2′-dimethoxy-1,1′-binaphthylene-4,4′-disulfonate ) and the cation part which consists of a racemic octahedrally coordinated zinc center defined six nitrogen atoms from three phen rings to form an inorganic chirality that can be resolution by chiral organic ligand, the 3D framework was formed through the strong H-bonding interaction between sulfonate and water. CCDC: 277924.     

Enantioselective syntheses of no-carrier-added (n.c.a.) (s)-4-chloro-2-[f] fluorophenylalanine and (s)-(α-methyl) -4-chloro-2-[f]fluorophenylalanine

(S)-4-Chloro-2-fluorophenylalanine and (S)-(α-methy)-4-chloro-2-fluorophenylalanine were synthesized and labeled with no carrier added (n.c.a.) fluorine-18 through a radiochemical synthesis relying on the highly enantioselective reaction between 4-chloro-2-[¹⁸F]fluorobenzyl iodide and the lithium enolate of (2S)-1-(tert-butyloxycarbonyl)-2-(tert-butyl)-3-methyl-1,3-imidazolidine-4-one for (S)-4-chloro-2-[¹⁸F]fluorophenylalanine and (2S,5S)-1-(tert-butyloxycarbonyl)-2-(tert-butyl)-3,5-dimethyl-1,3-imidazolidine-4-one for (S)-(α-methyl) -4-chloro-2-[¹⁸F] fluorophenylalanine. Quantities of about 20–25 mCi were obtained at the end of sy nthesi s, ready for injection after hydrolysis and high performance liquid chromatography (HPLC) purification, with a radiochemical yield of 17%–20% corrected to the end of bombardment after a total synthesis time of 90–105 min from [¹⁸F] fluoride. The enantiomeric excesses were shown to be 97% or more for both molecules without chiral separation and the radiochemical and chemical purities were 98% or better.     

Colorless poly(ether-imide)s deriving from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride(BPADA) and aromatic bis(ether amine)s bearing pendent trifluoromethyl groups

A series of poly(ether-imide)s (III) characterized by colorless, highly solubility was synthesized from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride(BPADA) and various fluorinated aromatic diamines (I_a-h) in DMAc via polycondensation to form poly(amic acid) (II), followed by chemical (C) and thermal (H) imidization. These polymers had inherent viscosities ranging from 0.60 to 1.3 dL/g. These polyimides were highly soluble in a variety of organic solvent such as amide-type, ether-type and chlorinated solvents. Moreover, these poly(ether-imide) films were almost colorless, with an ultraviolet-visible absorption cutoff wavelength below 390 nm and low b* value (a yellowness index) of 4.6-18.0. The III series showed strength tensile of 72-101 MPa, elongation at break of 11-25%, initial modulus of 1.5-2.0 GPa. The glass transition temperature (T_g) of III_a-h were in the range of 202-267 °C, and the decomposition temperature above 493 °C and left 40-65% char yield at 800 °C in nitrogen. They had the lower dielectric constants of 3.39-3.72 (1 MHz) and moisture absorptions in the range of 0.11-0.40%.     

Synthesis and properties of poly(amide-imide)s based on the diimide-diacid condensed from 2,2′- bis(4-aminophenoxy)biphenyl and trimellitic anhydride

A new dicarboxylic acid having a kinked structure was synthesized from the condensation of 2,2′-bis(4-aminophenoxy)biphenyl and trimellitic anhydride. A series of biphenyl-2,2′-diyl-containing aromatic poly(amide-imide)s having inherent viscosities of 0.23–0.94 dL/g was prepared by the triphenyl phosphite activated polycondensation from the diimide-diacid II with various aromatic diamines in a medium consisting of N-methyl-2-pyrrolidone (NMP), pyridine, and calcium chloride. Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents including NMP and N,N-dimethylacetamide (DMAc). Transparent, flexible, and tough films of these polymers could be cast from DMAc or NMP solutions. The glass transition temperatures of these polymers were in the range of 227–261°C and the 10% weight loss temperatures were above 520°C in nitrogen. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1169–1177, 1998     

New poly(amide-imide) syntheses. V. Preparation and properties of poly(amide-imide)s based on the diimide—diacid condensed from 2,2-bis[4-(4-aminophenoxy)phenyl]propane and trimellitic anhydride

A dicarboxylic acid ( 1 ) bearing two pre-formed imide rings, was prepared from the condensation of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and trimellitic anhydride. A new family of poly(amide-imide)s having inherent viscosities of 0.53–1.68 dL/g was prepared by the triphenyl phosphite activated polycondensation from the diimide—diacid I with various aromatic diamines in a medium consisting of N-methyl-2-pyrolidone (NMP), pyridine, and calcium chloride. Most of the resulting polymers showed an amorphous nature and were readily soluble in polar solvents such as NMP and N,N-dimethylacetamide. All the soluble poly(amide-imide)s afforded transparent, flexible, and tough films. The glass transition temperatures of these poly(amide-imide)s were in the range of 237–293°C and the 10% weight loss temperatures were above 508°C in nitrogen. © 1993 John Wiley & Sons, Inc.     

Synthesis and characterization of fluorine-containing polyamides derived from 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane by direct polycondensation

A fluorine-containing diamine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (BAPPH) ( II ), was synthesized in two steps on condensation of 2,2-bis(4-hydroxyphenyl)hexafluoropropane with p-chloronitrobenzene in the presence of potassium carbonate, giving 2,2-bis[4-(4-nitrophenoxy)phenyl]hexafluoropropane ( I ), followed by reduction with hydrazine monohydrate/Pd—C. Fluorine-containing polyamides and copolyamides having inherent viscosities 0.41–0.88 dL g⁻¹ were prepared by direct polycondensation of BAPPH with various aromatic diacids or with mixed diacids, by triphenyl phosphite and pyridine in N-methyl-2-pyrrolidinone (NMP). The polyamides were examined by elemental analysis, IR spectra, inherent viscosity, x-ray diffraction, solubility, DSC, and TGA. The diffractogram showed that the polyamides were crystalline except IVb , IVc , IVf , and Vc . Almost all polyamides were soluble in polar aprotic solvents. The polymers obtained from BAPPH lost no mass below 350°C, with 10% loss of mass being recorded above 467°C in nitrogen. These aromatic polyamides had glass transition temperatures in the 221–253°C range. © 1996 John Wiley & Sons, Inc.