The temperature dependence of the electrochemistry of the lithium-sulphur dioxide system

Value for the activation energy, U ^act, and the entropy change, S, for the reaction 2Li + S₂O ₄ ^2– Li₂S₂O₄+2e in acetonitrile have been found to be 72 kJ mol^–11 and — 0.3 kJ mol^–1 K^–1, respectively, by a combination of impedance techniques and the use of a temperature-controlled environment on commercially manufactured cells which acted as constant volume containers.     

The electrochemical oxidation of dimethyl disulfide—Anodic methylsulfanylation of phenols and aromatic ethers

The electrochemical oxidation of dimethyl disulfide was investigated in acetonitrile and dichloromethane. The nature of the oxidation strongly depends on the nucleophilicity of the solvent. In acetonitrile a one-electron oxidation is observed and the consecutive species did not exhibit any reactivity towards aromatic compounds subject to electrophile substitution. On the contrary, the oxidation of dimethyl disulfide in methylene chloride afforded a two-electron process with the formation of a species consistent with CH₃S⁺. Its reactivity towards phenols and aromatic ethers was confirmed and showed a selective monomethylsulfanylation in most of the cases.     

Temperature effects on soil organic sulphur mineralization and elemental sulphur oxidation in subtropical soils of varying pH

The increasing sulphur (S) deficiency in soils of several parts of world has led to the use of fertilizer S, an important factor in enhancing the production and quality of crops. Very limited information is available on the use of elemental sulphur (S⁰) as a fertilizer, its oxidation into SO4^2- and transformation into organic S in semiarid subtropical soils. We studied the impact of three temperature regimes on the mineralization of soil organic S, and the oxidation and immobilization of S⁰ in acidic (pH 4.9), neutral (pH 7.1) and alkaline (pH 10.2) subtropical soils of north-western India. Repacked soil cores were incubated under aerobic conditions (60% water-filled pore space) for 0, 14, 28 and 42 d with and without incorporated S⁰ (500 g g-1 soil). Temperature had profound effects on all three soils processes, the rates of mineralization of native soil organic S, oxidation of applied S⁰ and transformation of S⁰ into soil organic S being greatest at 36 °C, irrespective of soil pH. Mineralization of native soil organic S (without added S⁰) resulted in the accumulation of 39, 66 and 47 g SO4^2-–S g-1 soil in acidic, neutral and alkaline soil in 42 d period at 36 °C. Of the total mineralization, the majority (62 – 74%) occurred during the first 14 d period. Oxidation rate of added S⁰ during initial 14 d period at 36 °C was highest in alkaline soil (292 g S cm-2 d-1), followed by neutral soil ((180 g S cm-2 d-1) and lowest in acidic soil (125 g S cm-2 d-1). Of the applied 500 g S⁰ g-1 soil, 3.2 – 10.0%, 6.8 – 15.4% and 10.0 – 23.0% oxidized to SO4^2-, and 13.4 – 28.6%, 16.0 – 29.0% and 14.6 – 29.0% were transformed into organic S in 42 d period in acidic, neutral and alkaline soil, respectively. The results of our study suggest that in order to synchronize the availability of S with plant need, elemental S may be applied well before the seeding of crops, especially in acidic soil and in regions where temperature remains low. Substantial mineralization of native soil organic S in the absence of applied S⁰ and immobilization of applied S⁰ into organic S suggest that the role of soil biomass as source and sink could be exploited in long term S management.     

Thermogalvanic measurement of low partial pressures of oxygen with oxygen ion conductors: a disregarded possibility?

The thermogalvanic e.m.f. of O^2– conducting solid oxide cells can be used to detect small electronic contributions to the oxide conductivity, as a function of the ambient O₂ partial pressure. When this contribution is negligible, the thermocell can serve as an oxygen gauge. Gas-tightness of the oxide specimen is not required, in contrast to more conventional (concentration cell) techniques.List of symbols E potential (V) - p partial pressure (atm) - S entropy (J K^–1 mole^–1) - S ⁰ standard entropy (at 1 atm) - S transported entropy - ¯S partial (ionic) entropy - Q ^* ionic heat of transport (J mole^–1) - Seebeck coefficient or thermo (galvanic) power (V K^–1) - R,T,F usual significance     

Soluble polystyrenes with pyrrole pendant groups and their electroactive properties

Summary Four soluble styrenic polymers containing 3-substituted pendant pyrrole rings with ester or amide arm spacer were synthesized. Their electroactive characteristics were investigated by cyclic voltammetry. The chemical oxidation was accomplished by adding FeCl₃ into a solution of styrenic polymers dissolved in 1:1 mixture of dimethylformamide (DMF) and acetonitrile (ACN). The electrical conductivities of the chemically oxidized black powder of the styrenic polymers were in the range of 10^-1010^-9 S/cm.     

Enantioselective Biooxidation of Racemic trans‐Cyclic Vicinal Diols: One‐Pot Synthesis of Both Enantiopure (S,S)‐Cyclic Vicinal Diols and (R)‐α‐Hydroxy Ketones

Highly regio‐ and enantioselective alcohol dehydrogenases BDHA (2,3‐butanediol dehydrogenase from Bacillus subtilis BGSC1A1), CDDHPm (cyclic diol dehydrogenase from Pseudomonas medocina TA5), and CDDHRh (cyclic diol dehydrogenase from Rhodococcus sp. Moj‐3449) were discovered for the oxidation of racemic trans‐cyclic vicinal diols. Recombinant Escherichia coli expressing BDHA was engineered as an efficient whole‐cell biocatalyst for the oxidation of (±)‐1,2‐cyclopentanediol, 1,2‐cyclohexanediol, 1,2‐cycloheptane‐diol, and 1,2‐cyclooctanediol, respectively, to give the corresponding (R)‐α‐hydroxy ketones in >99% ee and (S,S)‐cyclic diols in >99% ee at 50% conversion in one pot. Escherichia coli (BDHA‐LDH) co‐expressing lactate dehydrogenase (LDH) for intracellular regeneration of NAD⁺ catalyzed the regio‐ and enantioselective oxidation of (±)‐1,2‐dihydroxy‐1,2,3,4‐tetrahydronaphthalene to produce the corresponding (R)‐α‐hydroxy ketone in >99% ee and (S,S)‐cyclic diol in 96% ee at 49% conversion. Preparative biotransformations were also demonstrated. Thus, a novel and useful method for the one‐pot synthesis of both vicinal diols and α‐hydroxy ketones in high ee was developed via highly regio‐ and enantioselective oxidations of the racemic vicinal diols.

     

Effect of anodically evolved gas bubbles on the rate of cathodic mass transfer in a vertical cylinder cell

Mass transfer coefficients were measured for the deposition of a copper from acidified copper sulphate solution at a vertical cylinder cathode stirred by oxygen evolved at a coaxial vertical cylinder lead anode placed upstream from the cathode and flush with it. The cathodic mass transfer coefficient was increased by a factor of 2.75–6.7 over the natural convection value depending on the rate of oxygen discharge at the lead anode and height of the cathode. The data were correlated by the equation:J=0.66(F_rR_e)^–0.21 An electrochemical reactor built of a series of vertical coaxial annular cells stirred by the counter electrode gases is proposed as offering an efficient way of stirring with no external stirring power consumption.Nomenclature a, b, c constants - C concentration of copper sulphate, mol cm^–3 - d cylinder diameter, cm - D diffusivity, cm² s^–1 - F Faraday's constant - g acceleration due to gravity, cm² s^–1 - h electrode height, cm - i current density at the oxygen generating anode, A cm^–2 - I _L limiting current density, A cm^–2 - K mass transfer coefficient, cm s^–1 - P gas pressure, atm - R gas constant, atm cm³ mol^–1 K^–1 - T temperature, K - u solution viscosity, poise - V oxygen discharge rate as defined by Equation 9, cm³ cm^–2 s^–1 or cm s^–1 - Z number of electrons involved in the reaction - J mass transferJ factor (S _tS_c ^0.66) - S _t Stanton number (K/V) - S _c Schmidt number (v/D) - S _h Sherwood number (Kh/D) - R _e Reynold's number (/Vh/u) - F _r Froude number (V ² /hg) - G_r Grashof number [gh ³/v² (1–)] - density of the solution, g cm^–3 - kinematic viscosity, cm² s^–1 - void fraction of the gas in the liquid-gas dispersion     

Recognition by nonaromatic and stereochemical subunit-containing polyamides of the four Watson-Crick base pairs in the DNA minor groove

In order to develop an optimal subunit as a T‐recognition element in hairpin polyamides, 15 novel chirality‐modified polyamides containing (R)‐α,β‐diaminopropionic acid (^Rβ), (S)‐α,β‐diaminopropionic acid (^Sβ), (1R,3S)‐3‐aminocyclopentanecarboxylic acid (^RSCp), (1S,3R)‐3‐amino‐cyclopentanecarboxylic acid (^RSCp), (1R,3R)‐3‐aminocyclopentanecarboxylic acid (^RRCp) and (1S,3S)‐3‐amino‐cyclopentanecarboxylic acid (^SSCp) residues were synthesized. Their binding characteristics to DNA sequences 5′‐TGC N CAT‐3′/3′‐ACG N′ GTA‐5′ ( N?N′ =A ? T, T ? A, G ? C and C ? G) were systemically studied by surface plasmon resonance (SPR) and molecular simulation (MSim) techniques. SPR showed that polyamide 4 , AcIm‐^Sβ‐ImPy‐γ‐ImPy‐β‐Py‐βDp (β/^Sβ pair), bound to a DNA sequence containing a core binding site of 5′‐TGC A CAT‐3′ with a dissociation equilibrium constant (K_D) of 4.5×10^?8 m. This was a tenfold improvement in specificity over 5′‐TGCTCAT‐3′ (K_D=4.5×10^?7 M ). MSim studies supported the SPR results. More importantly, for the first time, we found that chiral 3‐aminocyclopentanecarboxylic acids in polyamides can be employed as base readers with only a small decrease in binding affinity to DNA. In particular, SPR showed that polyamide 9 (^RRCp/β pair) had a 15‐fold binding preference for 5′‐TGCTCAT‐3′ over 5′‐TGCACAT‐3′. A large difference in standard free energy change for A ? T over T ? A was determined (ΔΔG^o=5.9 kJ mol^?1), as was a twofold decrease in interaction energy by MSim. Moreover, a 1:1 stoichiometry ( 9 to 5′‐TGC T CAT‐3′/3′‐ACG A GTA‐5′) was shown by MSim to be optimal for the chiral five‐membered cycle to fit the minor groove. Collectively, the study suggests that the (S)‐α‐amino‐β‐aminopropionic acid and (1R,3R)‐3‐aminocyclopentanecarboxylic acid can serve as a T‐recognition element, and the stereochemistry and the nature of these subunits significantly influence binding properties in these recognition events. Subunit (1R,3R)‐3‐aminocyclopentanecarboxylic acid broadens our scope to design novel polyamides.     

Inhibition of male response of drugstore beetles to stegobinone by its isomer

Stegobinone, (2S, 3R, 1R)-2,3,-dihy dro-2,3,5-trimethyl-6-(1-methyl-2-oxobutyl)-4H-pyran-4-one, the sex pheromone of drugstore beetles (Stegobium paniceum L.), elicited the pheromonal response from the males of the species in our bioassay system; however, the synthesized diastereomeric mixture of this compound was actually inactive to the males. Although the stegobinone isolated from the beetles of this species had significant activity, its enantiomeric [(±)-2S,3R,1S-] and diatereomeric [(±)-2S,3S,1RS-] isomers were inactive. Adding the (±)-2S,3R,1S isomer to stegobinone significantly reduced the male response. Furthermore, the activity of Stegobinone vanished on keeping it at room temperature for two weeks. In such a stored stegobinone sample, the presence of 2S,3R,1S isomer, the inhibitory component, was confirmed. This isomer might be produced by C-1 epimerization during storage.     

On the electrochemistry of 2,4,6-triphenylnitrobenzene and related compounds

Cyclic voltammetry at a glassy carbon electrode of 2,4,6-triphenylnitrobenzene (1) in DMF shows two reversible one-electron reductions. Preparative reduction of 1 yields 2,4,6-triphenylaniline under both acidic and alkaline conditions and in DMF in the presence of acetic anhydride. On reduction in dry DMF is formed a stable, violet radical anion with a broad maximum at 682 nm; in acetonitrile 1 is reported to yield an unstable bluish radical which is transformed to a yellow-purple radical with a maximum at 520 nm. Solid-state ¹³C NMR confirmed the existence of two stereoisomers in the crystals found by X-ray structure determination, whereas ¹³C NMR in chloroform at ambient temperature indicated one isomer in solution. 2,4,6-Triphenylaniline shows in CV in acetonitrile a reversible oxidation; in acetonitrile containing pyridine it is oxidized to azo(2,4,6-triphenylbenzene). This compound is in acidic aqueous DMF reduced to 2,4,6-triphenylaniline. The three phenyl groups act as electron donating groups during reductions akin to p-hydroxy or p-amino groups.     

Effect of surfactants on the rate of mass transfer at gas-evolving electrodes

The effect of sodium lauryl sulphate surfactant on the mass transfer coefficient of the cathodic reduction of ferricyanide ion and the anode oxidation of ferrocyanide ion at hydrogen- and oxygen-evolving electrodes, respectively, was studied. Also, the effect of sodium lauryl sulphate on the gas hold-up and cell voltage was studied. The presence of surfactant in the electrolyte was found to decrease the mass transfer coefficient by an amount ranging from 7.6 to 81% depending on the operating conditions. Gas hold-up and cell voltage were found to increase in the presence of surfactant.Nomenclature C concentration - F Faraday constant (96 487 C mol^–1) - I _I limiting current under natural convection - I current consumed in ferricyanide reduction or ferrocyanide oxidation during electrolysis with gas evolution - K mass transfer coefficient - V gas discharge rate - Z number of electrons involved in the reaction - gas hold-up     

Removal of tylosin from aqueous solution by UV/nano Ag/S2O 8 2− process : Influence of operational parameters and kinetic study

The present work deals with the photooxidative degradation of tylosin antibiotic (TYL) in the presence of potassium peroxydisulfate (K₂S₂O₈) irradiated by UV-C in the presence of immobilized nano silver. Effects of pH, temperature, peroxydisulfate concentration and immobilized nano silver dosage on the degradation efficiency of TYL were examined. Degradation efficiency was small when the oxidation was carried out in the absence of UV irradiation. Results showed that degradation of TYL increases with temperature, nano Ag and peroxydisulfate initial concentration and decreases with pH. Due to UV/nano Ag/S₂O ₈ ^2? processes, more than 90% of TYL can be degraded at room temperature in 35 min at an initial concentration of 50 mgl^?. Degradation reaction order of TYL by UV/nano Ag/S₂O ₈ ^2? process is 1.89. Meanwhile, the initial rates of degradation in UV/nano Ag/S₂O ₈ ^2? processes can be described well by the Langmuir-Hinshelwood kinetic model.     

Decomposition and oxidation of CH3 13CH2OH on A12O3, Pd/Al2O3, and PdO/Al2O3 catalysts

Temperature-programmed desorption (TPD) and oxidation (TPO) were used to investigate the decomposition and oxidation of ethanol on Al₂O₃, Pd/Al₂O₃, and PdO/Al₂O₃. Ethyl--¹³C alcohol (CH₃ ¹³CH₂OH) was adsorbed on the catalysts so that reaction pathways of the two carbons could be distinguished. Alumina was mainly a dehydration catalyst, but dehydrogenation was also observed and some carbon remained on the surface. In the presence of O₂, A1₂O₃ oxidized the decomposition products and the-carbon was oxidized faster. Ethanol, which was adsorbed on A1₂O₃, decomposed much faster on Pd/A1₂O₃ by diffusing to Pd and undergoing CO elimination to form CH₄,¹³CO, H₂, and surface carbon. On PdO/A1₂O₃, the decomposition was slower than on Pd/A1₂O₃ until lattice oxygen was extracted above 450 K; the decomposition products were oxidized by lattice oxygen. In the presence of gas phase O₂, Pd/Al₂O₃ was an active oxidation catalyst at low temperature, but lattice oxygen had to be extracted from PdO/A1₂O₃ before it had significant oxidation activity.     

Redox chemistry of H2S oxidation in the British Gas Stretford Process Part I: Thermodynamics of sulphur-water systems at 298 K

The thermodynamics of aqueous sulphur-water systems are summarized in the form of potential-pH diagrams, calculated from recently reported critically assessed standard Gibbs energies of formation of the species considered. However, there is convincing evidence from the literature that a value of pK _a(HS^–) = 17–19 is appropriate, whereas a value of 13 is widely accepted; hence, the higher value of 19, corresponding to G _f ⁰ (S^2–) = 120.5 kJ mol^–1 , was used in these calculations, rather than G _f ⁰ (S2-) = 86.31 kJ mol^–1 quoted in the main data source.Under ambient conditions, only – 2 (sulphide), 0 (elemental sulphur) and + 6 (sulphate) oxidation states are thermodynamically stable in water, which is predicted to be oxidized by peroxodisulphate (H₂ S₂ O₈/SO ₈ ^2– and peroxomonosulphate (HSO ₅ ^– /SO ₅ ^2– ). However, when sulphate is excluded from the calculations to allow for the large energy of activation/slow kinetics of its formation from sulphide, then other sulphoxy species appear on the diagram for what is then a metastable system. Similarly, if all sulphoxy species (i.e. any species with oxidation states > 0) are excluded, then polysulphide ions (S _n ^2– , 2 n 5) have areas of predominance at high pH, each with a narrow potential window of predominance. Hence, this information is complemented with S _n ^2– /HS^– activity-potential diagrams at pH 9 and 14.Some species have no area of stability even on the metastable diagrams. Hence, potential-pH diagrams are also presented for the sulphite-dithionite system (excluding elemental sulphur), and that involving peroxomonosulphate (HSO ₅ ^– /SO ₅ ^2– ) in place of peroxodisulphate (H₂S₂O₈/SO ₈ ^¨– ).     

A study of factors that control biosynthesis of the compounds which comprise the boll weevil pheromone

Biosynthesis of the four monoterpene compounds that comprise the pheromone of the male boll weevil,Anthonomus grandis Boheman, [1, (+)-cis-2-isopropenyl-1-methylcyclobutaneethanol; II, (Z)-3,3-dimethyl-^1,-cyclohexaneethanol; III, (Z)-3,3-dimethyl-^1,-cyclohexaneacetaldehyde; and IV, (E)-3,3-dimethyl-^1,-cyclohexane-acetaldehyde] was studied. More pheromone was biosynthesized in the summer months, somewhat less was produced by males in the presence of females than by isolated males, and the pheromone was concentrated in the gut and surrounding tissue of the abdomen of the males. Incubation of abdomens with the pheromone alcohols yielded related hydrocarbons, aldehydes, and alcohols, which suggested the presence of several enzyme systems. Boll weevils were able to allylically oxidize myrcene and limonene to alcohols, a capability that suggests pheromone precursors may be at least in part inhaled rather than ingested. The hemolymph may then transport the precursor to the gut or some alternative site where allylic oxidation to the pheromone occurs.Coleoptera: Curculionidae.In cooperation with the Mississippi Agricultural and Forestry Experiment Station, Mississippi State, Mississippi 39762. Received for publication.     

Molecular architectures of four‐arm star‐shaped styrene‐butadiene copolymer

To understand the molecular architectures of styrene‐butadiene four‐arm star (SBS) copolymers, a size exclusion chromatography combined with laser light scattering (SEC‐LLS) has been used to determine their weight‐average molecular weight (M_w) and radius of gyration (〈S²〉^1/2), and a new method for the establishment of the Mark‐Houwink equation from one sample has been developed. Based on the Flory viscosity theory, we successfully have reduced the 〈S²〉^1/2 values of numberless fractions estimated from many experimental points in the SEC chromatogram to intrinsic viscosities ([η]). For the first time, the dependences of 〈S²〉^1/2 and [η] on M_w for the four‐arm star SBS in tetrahydrofuran at 25°C were found, respectively, to be 〈S²〉^1/2 = 2.62 × 10^?2 M (nm) and [η] = 3.68 × 10^?2 M (mL/g) in the M_w range from 1.4 × 10⁵ to 3.0 × 10⁵. From data of [η] and 〈S²〉^1/2 for linear and star SBS, we have obtained the information about the branching, namely, the ratios (g and g′) of 〈S²〉 and [η] for star SBS to that of the linear SBS of the same molecular weight, which agree with theoretical predictions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 961–965, 2005     

Electrochemical behaviour of tetraazamacrocyclic nickel(II) complexes functionalized with crown ethers

Tetraazamacrocyclic nickel(II) complexes linked by the system of conjugated double bonds with one or two benzo-15-crown-5 moieties (2Ni and 3Ni) were synthesized and characterized. The CV of these complexes in acetonitrile (ACN) solution exhibited reversible Ni^II/III redox process. At more positive potentials oxidation of the bezno-15-crown-5 ether (B15C5) moiety was found. In complexes 2Ni and 3Ni redox potential of Ni^II/III did not change after the interactions of alkali and alkaline earth metal cations with B15C5 unit. However, the presence of guest cations caused a significant change of B15C5 oxidation potential. Complexation of two Cl⁻ anions to the coordinated Ni^II in 2Ni and 3Ni resulted in an appreciable shift of both Ni^II/III and B15C5 redox processes after addition of metal cations. Behaviour of complexes 2Ni and 3Ni was compared with behaviour of similar Cu^II complexes.     

Spatio-kinetic variation of methane oxidizing bacteria in paddy soil at mid-tillering: effect of N-fertilizers

Laboratory experiments were conducted to evaluate the variation ofpopulation size of methanotrophs (MOB) and CH₄ oxidation pattern inflooded rice soils sampled at three spatial points (rhizosphere, bulk and baresoils). Rhizosphere soil had higher MOB population size (301.1 ×10⁵ cells g^–1 dry soil) than bulk(37.2× 10⁵ cells g^–1 dry soil) andbare soil (19.1 × 10⁵ cells g^–1dry soil). The population size of MOB followed a decreasing trend with respectto fertilizer (urea NH₄NO₃ NH₄Cl control). The result indicated that rhizosphere soil presented thestrongestCH₄ oxidation activities, as shown by the highest values of the twokinetic parameters (K _m(app) andV _max). K _m andV _max increased significantly from bare to bulkto rhizosphere soil in control and fertilized soil and ranged from 6.2 to 133.2g g^–1 dry soil and from 0.03 to 0.41g h^–1 g^–1 dry soil,respectively. The differences in K _m andV _max among the three soils (rhizosphere, bulkand bare) in this study could be due to differential species composition ofmethanotrophic community and/or to conditioning of MOB under different soilmicroenvironments. The present study has demonstrated a competitive inhibition effectof NH₄ ⁺-N on CH₄ oxidation.     

Selective Photo-Assisted Oxidation of Methane into Formaldehyde on Mesoporous VO x /SBA-15 Catalysts

Mesoporous VO _x /SBA-15 samples have been prepared by different impregnation methods, characterized by N₂ adsorption and diffuse reflectance UV–visible spectroscopy, and their photocatalytic reactivity evaluated for the selective oxidation of methane with oxygen at 220 °C under UV irradiation. Vanadium in dehydrated VO _x /SBA-15 samples was found to be predominantly as isolated four-coordinated V⁵⁺ species, especially at V loading below 2.5 wt%. VO _x /SBA-15 catalysts prepared by impregnation with an aqueous solution of ammonium metavanadate (AMV) showed a maximum rate of formation of formaldehyde of 525 mol g^-1 h^-1 (selectivity of 93.8 mol%) at a vanadium content of 2.65 wt%. Both the rate of formation and selectivity of formaldehyde were improved when vanadium was impregnated on the SBA-15 support from a vanadyl sulfate methanolic solution (rate of formation of HCHO = 733 mol g^-1 h^-1, selectivity = 95.4 mol%). VO _x /SBA-15 catalysts were seen to be more effective for the selective photo-assisted oxidation of methane than VO _x /SiO₂ catalysts.     

Preparation of highly conducting and spin-probed polypyrroles using coupled electrochemical-chemical synthesis in the presence of nitroxyl radicals

Summary A new method for the synthesis of conducting polypyrroles (PPy), based on chemical and combined electrochemical-chemical oxidation of pyrrole monomers in the presence of nitroxyl radical (TEMPOL-2,2,6,6-tetramethyl-4-hydroxy-1-oxy-piperidyl) as oxidation agent (in its oxidation state) and redox mediator respectively is described. The PPy films obtained are extremely porous and the electrical conductivity () of the resulting PPy samples ranges from 1 to 100 S cm^–1. PPy prepared in aqueous solutions has a lower conductivity 1 S cm^–1 as compared to the PPy prepared in acetonitrile solutions with conductivity of about 100 S cm^–1. The PPy films are quite compact and thick films (1 mm) can be pealed off from the electrode surface and pressed as a disc for further studies. Only after partial reduction of polypyrrole film the spin-probed PPy was obtained. The concentration of nitroxyl radicals incorporated in the polymer matrix can be changed using various degrees of polymer reduction. The anisotropic broadening of the observed ESR lines indicates a low mobility of incorporated nitroxyl radicals in the PPy matrix. The electronic interaction between the nitroxyl groups and the paramagnetic centers of the polymer chains, polarons, causes an ESR line broadening of polaron signal both on air (1.1 mT) and in vacuum (0.7 mT) as compared to unmodified PPy (0.2 mT on air, 0.05 mT in vacuum).