Electrosyntheses of high quality poly(5-methylindole) films in mixed electrolytes of boron trifluoride diethyl etherate and diethyl ether

High quality poly(5-methylindole) (P5MeI) films, especially with good fluorescence properties, were synthesized electrochemically by direct anodic oxidation of 5-methylindole in boron trifluoride diethyl etherate (BFEE) containing additional 50% diethyl ether (EE) (by volume). The oxidation potential onset of 5-methylindole in this medium was measured to be only 0.84 V vs. SCE, which was much lower than that determined in acetonitrile + 0.1 mol L⁻¹ TBATFB (1.08 V vs. SCE). P5MeI films obtained from this medium showed good electrochemical behavior and good thermal stability with conductivity of 10⁻² S cm⁻¹, indicating that BFEE was a better medium than acetonitrile for the electrosyntheses of P5MeI films. Dedoped P5MeI films were thoroughly soluble in strong polar solvent such as dimethyl sulfoxide (DMSO). ¹H NMR spectroscopy and FT infrared spectrum of dedoped P5MeI films strongly suggested that the monomers were linked via the positions 2 and 3. Fluorescent spectral studies indicated that P5MeI was a good violet-blue light emitter with the excitation and emission wavelength of 310 nm and 418 nm, respectively. To the best of our knowledge, this is the first case that 5-methyl group substituted polyindole films with good fluorescence properties can be electrodeposited.     

Electrosyntheses of free-standing poly(dibenzo-18-crown-6) films in boron trifluoride diethyl etherate on stainless steel electrode

High-quality free-standing poly(dibenzo-18-crown-6) (PDBC) films with a conductivity of 4.1 × 10⁻² S cm⁻¹ and good thermal stability were synthesized electrochemically on stainless steel electrode by direct anodic oxidation of dibenzo-18-crown-6 (DBC) in pure boron trifluoride diethyl etherate (BFEE). In this medium, the oxidation potential onset of DBC was measured to be only 0.98 V vs. SCE, which was much lower than that in acetonitrile + 0.1 mol L⁻¹ Bu₄NBF₄ (1.45 V vs. SCE). PDBC films obtained from this medium showed good redox activity and stability in BFEE. The structural characterization of PDBC was performed using UV-vis, FTIR spectroscopy. The results of quantum chemistry calculations of DBC monomer and FTIR spectroscopy of PDBC films indicated that the polymerization mainly occurred at C₍₄₎ and C₍₅₎ positions). Fluorescent spectral studies indicated that PDBC was a blue light emitter. To the best of our knowledge, this is the first report on the electrodeposition of free-standing PDBC films.     

Electrosyntheses of poly(2,3-benzofuran) films in boron trifluoride diethyl etherate containing poly(ethylene glycol) oligomers

Visible-light transparent high-quality substrate-supported poly(2,3-benzofuran) (PBF) film has been successfully electrosynthesized by direct anodic oxidation of 2,3-benzofuran on stainless steel sheet in boron trifluoride diethyl etherate (BFEE) containing 10% poly(ethylene glycol) (PEG) with molar mass of 400 (by volume). The oxidation potential of 2,3-benzofuran in this medium was measured to be only 1.0 V vs. SCE, which is lower than that determined in acetonitrile + 0.1 M Bu₄NBF₄ (1.2 V vs. SCE). The PBF films obtained in this media showed good electrochemical behaviors and good thermal stability with conductivity of 10⁻² S cm⁻¹, and the doping level of as-prepared PBF films was determined to be only 8.9%. The structure and morphology of the polymer were investigated by UV-vis, infrared spectroscopy and scanning electron microscopy (SEM), respectively. To the best of our knowledge, this is the first case for the syntheses of PBF films.     

Electrosyntheses and characterization of poly(9-bromophenanthrene) in boron trifluoride diethyl etherate

A novel semi-conducting polymer poly(9-bromophenanthrene) (P9BP) was synthesized electrochemically by direct anodic oxidation of it is monomer 9-bromophenanthrene (9BP) in boron trifluoride diethyl etherate (BFEE). The oxidation onset potential of 9BP in this medium was measured to be only 1.33 V vs. saturated calomel electrode (SCE). P9BP films obtained from BFEE showed good electrochemical behavior and nice thermal stability with electrical conductivity of 0.03 S cm⁻¹. FTIR and ¹H NMR spectra together with theoretical quantum chemistry calculations indicated that the P9BP was mainly grown via the coupling of the monomer at C₃ and C₆ positions. Furthermore, P9BP exhibited strong electrochromic nature from opaque green to light yellow between the doped and dedoped states on ITO electrode in solid state. Fluorescence spectral studies indicated that P9BP was a blue light emitter.     

Electrosyntheses of freestanding polyindole films in boron trifluoride diethyl etherate

High‐quality freestanding polyindole (PIn) films were synthesized electrochemically through the direct oxidation of indole in pure boron trifluoride diethyl etherate (BFEE). The oxidation potential of indole in this medium was measured to be only 0.86 V versus a saturated calomel electrode, which was lower than that determined in acetonitrile/0.1 mol L^?1 Bu₄NBF₄. PIn films obtained from this medium showed better electrochemical behavior and better thermal stability with a conductivity of 10^?1 S cm^?1, and this indicated that BFEE was a better medium than acetonitrile for the electrosyntheses of PIn films. Structural studies showed that the polymerization of indole ring occurred at the 2,3‐position. As‐formed PIn films could be partly dissolved in acetone, acetonitrile, tetrahydrofuran, and so forth. Fluorescent spectral studies indicated that PIn was a good blue‐light emitter. To the best of our knowledge, this is the first report on the fluorescence of PIn. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1444–1453, 2005     

Electrosynthesis of highly conducting poly(1,5-dihydroxynaphthalene) in BF3·Et2O

Direct anodic oxidation of 1,5-dihydroxynaphthalene (DHN), an important derivative of naphthalene, led to the formation of high-quality semiconducting poly(1,5-dihydroxynaphthalene) (PDHN) on stainless steel sheets in boron trifluoride diethyl etherate (BFEE). The onset oxidation potential of DHN in this medium was measured to be only 0.78 V vs. SCE, which was lower than that determined in traditional acetonitrile containing 0.1 mol/L tetrabutylammonium tetrafluoroborate (0.98 V vs. SCE). As-formed PDHN films showed good redox activity and stability, together with interesting electrochromic property from brown (doped) to yellow-green (dedoped). Structural characterization, including FTIR, ¹H NMR, and quantum chemistry calculations, indicated that the polymerization of DHN probably occurred at C₄ and C₈ positions. Moreover, thermal analysis revealed that PDHN displayed better thermal stability than that synthesized by chemical method. The fluorescence spectral studies, together with the electrical tests, showed that PDHN was a good blue light-emitter (fluorescence quantum yield higher than 0.1) with an electrical conductivity of as high as 0.46 S/cm.     

Low potential electrosyntheses of free‐standing poly(dibenzofuran) films in mixed electrolytes of boron trifluoride diethyl etherate and trifluoroacetic acid

Free‐standing poly(dibenzofuran) (PDBF) films were synthesized electrochemically by direct anodic oxidation of dibenzofuran in mixed electrolytes of boron trifluoride diethyl etherate (BFEE) containing certain amount of trifluoroacetic acid (TFA). The oxidation potential of dibenzofuran in pure BFEE was measured to be only 1.31 V versus saturated calomel electrode (SCE). This value was much lower than that determined in acetonitrile + 0.1 mol L^?1 TBATFB (2.14 V vs. SCE). The addition of TFA to BFEE can further decrease the oxidation potential of the monomer to 1.07 V versus SCE in the mixed electrolyte of BFEE + 30% TFA. PDBF films obtained from this medium showed good electrochemical behavior, good electrochromic properties, and good thermal stability with conductivity of 10⁰ S cm^?1. FTIR and ¹H NMR spectra showed that the polymer was grown mainly via the coupling of the monomer at C₍₃₎ C₍₁₀₎ or C₍₄₎ C₍₉₎ positions (Scheme 1). As‐formed PDBF films were partly soluble in tetrahydrofuran (THF) or chloroform. Fluorescent spectral studies indicated that either soluble or PDBF in solid state was a good blue light PDBF emitter. To the best of our knowledge, this is the first report that free‐standing PDBF films can be electrodeposited. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1125–1135, 2006     

Electrosyntheses of high‐quality poly(5‐nitroindole) films in boron trifluoride diethyl etherate containing additional diethyl ether

High‐quality poly(5‐nitroindole) (PNP) films were synthesized electrochemically by the direct anodic oxidation of 5‐nitroindole in boron trifluoride diethyl etherate (BFEE) containing additional 10% diethyl ether (EE) (by volume). The addition of EE to BFEE could improve the solubility of the monomer. The oxidation potential onset of 5‐nitroindole in this medium was measured to be only 1.04 V versus a saturated calomel electrode (SCE), which was much lower than that determined in acetonitrile and 0.1 mol L^?1 tetrabutylammonium tetrafluoroborate (1.53 V vs SCE). PNP films obtained from this medium showed good electrochemical behavior and good thermal stability with a conductivity of 10^?2 S cm^?1; this indicated that BFEE containing 10% EE was a suitable medium for the electrosyntheses of PNP films. Structural studies showed that the polymerization of the 5‐nitroindole ring occurred at the 2,3‐position. As‐formed PNP films were thoroughly soluble in the strong polar organic solvent dimethyl sulfoxide and partly soluble in tetrahydrofuran or acetone. Fluorescent spectral studies indicated that PNP was a good green‐light emitter, with excitation and emission wavelengths of 420 and 550 nm, respectively. To the best of our knowledge, this is the first time that nitro‐group‐substituted high‐quality conducting polymer films have been electrodeposited. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3986–3997, 2005     

Low potential electrochemical polymerization of diphenyl ether and characterization of its polymers

High‐quality poly(diphenyl ether) (PDPE) films with electrical conductivity of 4.4 × 10^?1 S cm^?1 were synthesized electrochemically by direct anodic oxidation of diphenyl ether (DPE) in boron trifluoride diethyl etherate (BFEE) containing 5% concentrated sulfuric acid (SA) (by volume). The oxidation potential onset of DPE in pure BFEE was measured to be only 1.37 V versus a saturated calomel electrode (SCE), which was much lower than that determined in acetonitrile + 0.1 mol L^?1 tetrabutylammonium tetrafluoroborate (1.98 V vs. SCE). The addition of SA to BFEE can further decrease the oxidation potential onset of the monomer to 1.18 V versus SCE in the mixed electrolyte of BFEE + 5% SA. PDPE films obtained from this medium showed good redox activity and stability even in concentrated SA. Dedoped PDPE films were partly soluble in the strong polar organic solvent dimethyl sulfoxide. Fluorescent spectral studies indicated that soluble PDPE was a good blue‐light emitter with a quantum yield of 0.30. Infrared spectroscopy and quantum chemistry calculations indicated that the electropolymerization of DPE occurred mainly at C₄ and C_4′. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5932–5941, 2007     

三氟化硼乙醚/乙酸混合电解质中芴的电化学聚合

在三氟化硼V(乙醚):V(乙酸)=4:5的混合电解质体系中直接氧化芴,获得芴聚合物膜,其电导率为0.5 S cm-1,高于在纯三氟化硼乙醚中制得的聚芴的电导率0.25 S cm-1.在三氟化硼乙醚:乙酸=4:5的混合电解质体系中获得的聚芴膜具有良好的电化学性质和化学稳定性.FTIR,1H-NMR和量化计算表明反应发生在...     

Electrosyntheses of high‐quality polyphenanthrene in the electrolyte of boron trifluoride diethyl etherate containing trifluoroacetic acid

A novel inherently conducting polymer, high‐quality polyphenanthrene (PPh) films were synthesized electrochemically by direct anodic oxidation of phenanthrene (Ph) in boron trifluoride diethyl etherate (BFEE) containing a certain amount of trifluoroacetic acid (TFA). The oxidation potential of Ph in this medium was measured to be only 0.63 V versus SCE, which was greatly lower than that determined in acetonitrile + 0.1 mol L^?1 Bu₄NBF₄ (1.55 V vs. SCE). The electrolytes of BFEE containing TFA enable facile anodic oxidation of Ph monomer; however, similar oxidation using acetonitrile never produces such a polymeric material. PPh films obtained from this medium showed good redox activity and stability even in concentrated sulfuric acid. Dedoped PPh films were partly soluble in polar solvent such as CH₂Cl₂, acetone, tetrahydrofuran, and dimethyl sulfoxide. Fluorescent spectral studies indicate that PPh is a good blue‐light emitter. The structure and morphology of the polymer were studied by UV–vis spectroscopy, FTIR spectroscopy, ¹H NMR spectroscopy, and scanning electron microscopy, respectively. The results of quantum chemistry calculations of Ph monomer and the spectroscopies of dedoped PPh indicated the polymerization mainly occurred at C₍₉₎ and C₍₁₀₎ positions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3929–3940, 2007     

Electrosyntheses of freestanding poly (3-(4-fluorophenyl)thiophene) films in boron trifluoride diethyl etherate

High quality free-standing poly (3-(4-fluorophenyl)thiophene) (PFPT) films with conductivity of 10⁻¹ S/cm were electrosynthesized in boron trifluoride diethyl etherate (BFEE) by direct anodic oxidation of the monomer 3-(4-fluorophenyl)thiophene (FPT) on stainless steel sheet. As-formed flexible and shiny PFPT films can be cut into various shapes by a knife or a pair of scissors. The structure, thermal stability and morphology of PFPT films were studied by FT-infrared, UV-vis, Raman spectroscopy thermogravimetric analysis and scanning electron microscopy, respectively.     

Electrochemical behavior of atomoxetine and its voltammetric determination in capsules

In this work, the electrochemical behavior and the analytical application of atomoxetine, a selective noradrenaline reuptake inhibitor, are studied. Atomoxetine, studied by differential pulse voltammetry and cyclic voltammetry on a glassy carbon electrode, exhibited an anodic response in aqueous media with pH between 1.5 and 7. In non-aqueous medium (acetonitrile), the drug exhibited two irreversible oxidation peaks that are diffusion controlled. From chronocoulometric studies in acetonitrile, it was determined that each oxidation signal involves two and four electrons, respectively. For analytical purposes, a differential pulse voltammetry technique in 0.1 mol L⁻¹ perchloric acid was selected, which exhibited adequate figures of merit. The percent recovery was 96.6 ± 1.2 and the detection and quantitation limits were 6.9 × 10⁻⁵ and 1.0 × 10⁻⁴ mol L⁻¹, respectively. Also, results indicate that excipients do not interfere with the oxidation signal of atomoxetine, which leads to the conclusion that the developed method is satisfactorily selective for atomoxetine quantification in pharmaceuticals with no prior separation or extraction necessary. Finally, the proposed voltammetric method was successfully applied to both the assay and the uniformity content of atomoxetine in capsules. For comparison, high-performance liquid chromatography analysis was also performed.     

Studies on fluorene stability in different liquid media

When applying chromatography the analyst is faced with problems, among others, caused by changes undergoing in original samples or extract. Storage conditions should ensure their stability. It has been found that degradation processes can not be eliminated entirely, but they can be slowed down considerably.A selection of eight liquid media known as good solvents to store fluorene for a long period of time, have been examined with respect to avoid once of degradation. Fluorene degradation (1 mg l⁻¹ and 10 mg l⁻¹) was studied in acetonitrile, methanol, water, dimethyl sulfoxide, hexane, cyclohexane and dichloromethane. The process was monitored for 3 months using HPLC coupled to diode array detection and electrospray MS.The influence of such factors as light, naturally occurring bacterial flora in water samples, and solvent on stability of fluorene was investigated.The results can be helpful in selecting appropriate conditions and allowable time for storing samples extracts for analysis of polycyclic aromatic aromatic hydrocarbons. Therefore, understanding the mechanism responsible for PAHs degradation is required.The fact that salicylic acid and 9-fluorenone are formed during degradation of fluorene indicates that degradation is due to the photochemical and/or microbial processes.     

三氟化硼乙醚溶液中聚(二苯并呋喃)的电化学合成

在三氟化硼乙醚-硫酸混合电解质溶液中,二苯并呋喃直接阳极氧化聚合可以获得高质量聚(二苯并呋喃)膜.二苯并呋喃在纯三氟化硼乙醚中的起始氧化电位为1.30 VvsSCE,远低于单体在0.1 mol.L-1Bu4NBF4乙腈溶液中的起始氧化电位(2.14 V).硫酸的加入进一步降低了二苯并呋喃的氧化电位.在三氟化硼乙醚-硫酸混合电解质溶液中,二苯并呋喃的起始氧化电位可降低至1.0 V;同时在该体系中获得的聚(二苯并呋喃)膜具有良好的电化学性质和荧光性质.     

Facile electrosynthesis and thermoelectric performance of electroactive free-standing polythieno[3,2-b]thiophene films

Polythieno[3,2-b]thiophene (PTT) was electrosynthesized by facile anodic oxidation of thieno[3,2-b]thiophene (TT) in three systems: boron trifluoride diethyl etherate (BFEE), acetonitrile (ACN), and dichloromethane solutions. The onset oxidation potential of TT in BFEE was determined to be 0.62?V vs. Ag/AgCl, which was much lower than those in ACN and dichloromethane solutions. PTT films exhibited excellent electrochemical property, high thermal stability, good redox activity, and stability. Free-standing PTT films with good mechanical property can be obtained from BFEE solution, whose structure and morphology were characterized by FT-IR, UV?Cvisible spectra, and scanning electron microscopy. With an electrical conductivity of 1.5?S?cm^?1 and a Seebeck coefficient of 85???V?K^?1 at 306?K, the as-prepared free-standing PTT films showed a certain thermoelectric property. The dimensionless figure-of-merit of PTT films was estimated to be 2.3?×?10^?3 at 306?K, which was much higher than those of some organic thermoelectric materials reported previously. All these results indicated that PTT films may have potential applications in the thermoelectric field.     

9,9-二乙基芴在三氟化硼乙醚中的电化学聚合

在三氟化硼乙醚(BFEE)中,9,9-二乙基芴(DEF)直接阳极氧化聚合可以获得高质量聚(9,9-二乙基芴)膜(PDEF,电导率2×10-2S.cm-1).DEF在BFEE中的起始氧化电位为1.20 VvsSCE,远低于单体在0.1 mol.L-1Bu4NBF4的CH3CN溶液中的起始氧化电位(1.70 V).在BFEE中获得的PDEF膜具有良好的电化学性质.红外光谱和1H NMR结果表明聚合反应主要发生在2,7位.     

Electrosynthesis of blue-light-emitting oligo(1-bromopyrene) with favorable solubility

Bromo-group-substituted oligopyrene films were electrochemically synthesized by direct anodic oxidation of 1-bromopyrene (BrP) in boron trifluoride diethyl etherate (BFEE). The oxidation potential of BrP was measured to be approximately 0.52 V (vs. Ag/AgCl), which was much lower than that detected in a neutral electrolyte such as acetonitrile (1.2 V vs. Ag/AgCl) and CH₂Cl₂ (1.25 V vs. Ag/AgCl). Oligo(1-bromopyrene) (OBrP) films showed good redox activity in both BFEE and concentrated sulfuric acid. Fourier transform infrared spectroscopy, ¹H NMR, and theoretical calculations showed that the electropolymerization of the BrP monomer mainly occurred at the C₍₃₎, C₍₆₎, and C₍₈₎ positions. As-formed OBrP was a typical blue light emitter with fluorescent quantum yields of 0.27, also emitted strong and bright blue photoluminescence at excitation of 365 nm UV light. Furthermore, the films were readily soluble in dimethyl sulfoxide, CH₂Cl₂, acetonitrile, and acetone. All these results indicate that the striking OBrP films have many potential applications in various fields, such as optoelectronic materials, DNA fluorescence probes, and electrochemical sensors.     

Synthesis and oxidative polymerization of dialkyl fluorene-9,9-dicarboxylates

Novel long-chain dialkyl fluorene-9,9-dicarboxylates were synthesized by treating fluorene with lithium diisopropylamide followed by alkyl chloroformates. The fluorene derivatives were readily electro-oxidized to form electroactive films on the surface of a glassy carbon electrode. From the viewpoint of suitable potential window (from −2.5 to 1.5 V vs Ag/Ag⁺), cyclic voltammograms of the films indicated the electroactive properties of the fluorene derivatives that make them good candidates for electrochemical capacitor materials.     

Effect of monomer molecular flow on electrode surface on the structure of poly(α-tetrathiophene) obtained by anodic polymerization

Different structures have been found for poly(α-tetrathiophene) [poly(α-4TF)] electrosynthesized on Pt by anodic oxidation of 1.0 mM monomer solutions in media such as 45:35:20 (v/v/v) acetonitrile/THF/DMF, 45:35:20 (v/v/v) acetonitrile/ethanol/DMF and 72:28 (v/v) acetonitrile/DMF containing 0.1 M LiClO₄; as well as 72:28 (v/v) acetonitrile/DMF with 0.1 M NaClO₃, under dynamic and static conditions at 25 °C. In all cases the polymer was generated by chronoamperometry at 1.000 V vs. Ag∣AgCl, corresponding to the first oxidation peak detected by cyclic voltammetry. Uniform, adherent, insoluble and black polymer films were obtained under these conditions. The resulting structures have been elucidated by combining the information of their IR spectrum, n_ox-value and doping level of the counterion. The degree of crosslinking of every polymer has been quantified and related to the molecular flow of monomer on the Pt electrode. A monomer concentration flow between 4 × 10⁻⁶ and 5 × 10⁻⁶ mmol cm⁻² s⁻¹ was determined as the limiting value below which the polymer grows with crosslinking. This value corresponds to the electropolymerization rate of α-4TF by Pt area unit at 25 °C.