New Electrochemically Active Highly Sulfurized Polyconjugated Polymers

The electrochemical activity of new highly sulfurized polyconjugated polymers is studied. The polymers, polythienothiophene, poly(4,5,6,7-tetrathieno-4,5,6,7-tetrahydro-2,3-dehydrobenzothiophene), poly(6-methylthieno[2,3-b]pyridine-4-thione-5-thiol), and poly(6H-thieno[2,3-b]-azepine-6,7(8H)-dithione) are obtained in a deep sulfurization of polyethylene, polystyrene, and poly(5-vinyl-2-methylpyridine) by elemental sulfur. Employed as active cathodic material in lithium batteries, these polymers ensure their prolonged cycling with specific discharge capacity of up to 339 mA h/g. The effect of the conducting additive and electrolyte on the energy capacity and cycling of polymer cathodes in lithium batteries is discussed.     

Sulfurization of polymers

Polyethylene exhaustively sulfurized with elemental sulfur shows paramagnetic (spin concentration 2.7–9.7·10¹⁹ sp g⁻¹,g=2.0041–2.0045, ΔH=0.53–0.62 mT) and redox properties, which was demonstrated by both voltammetric and chemical methods (sodium reduction in liquid ammonia). The high concentration of unpaired electrons, the character of the electrochemical activity, and the chemical properties are in agreement with the presence in the polymers of polyconjugated ladder polythiophene and parquet polynaphtho-thienothiophene structures along with polyene-polysulfide blocks. The use of the polymers under consideration as an active cathode material in lithium batteries enables their repeated cycling with a specific charge capacitance of 150–340 mA hg⁻¹.     

Cyanoacetylene and Its Derivatives: XXXII. Addition of Ammonia and Methylamine to 4-Hydroxy-4,4-diphenyl-2-butynenitrile

Nucleophilic addition of ammonia (25% aqueous solution) and methylamine to 4-hydroxy-4,4-diphenyl-2-butynenitrile occurs under mild conditions to afford 4-amino(or methylamino)-2,5-dihydro-5,5-diphenyl-2-iminofurans. 4-Hydroxy-4,4-diphenyl-2-butynenitrile in anhydrous liquid ammonia gives rise to 3-amino-4-hydroxy-4,4-diphenyl-2- butenenitrile which is quantitatively converted into the corresponding iminodihydrofuran or iminodihydrofuran hydrochloride in the presence of 10 wt % of KOH or gaseous hydrogen chloride. 4-Amino- and 4-methylamino-2-iminofurans react with 4-hydroxy-4-methyl-2-pentynenitrile to give 3-(4-amino- and 4-methylamino-5,5-diphenyl-2,5-dihydrofuran-2-ylideneamino)-4-hydroxy-4-methyl-2-pentenenitriles.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 64–69.Original Russian Text Copyright © 2005 by Mal’kina, Sokolyanskaya, Kudyakova, Sinegovskaya, Albanov, Shemyakina, Trofimov.     

Cyanoacetylene and Its Derivatives: XXXIII. One-Pot Stereoselective Synthesis of Bis-iminodihydrofurans from 4-Hydroxy-4-methyl-2-pentynonitrile and Aromatic Amines

4-Hydroxy-4-methyl-2-pentynonitrile reacts with aniline, N-methylaniline, and 2-naphthylamine under mild conditions (20–80°C) to afford the corresponding 4-arylamino-2-(2-imino-5,5-dimethyl-2,5-dihydro-4-furylimino)-5,5-dimethyl-2,5-dihydrofurans in one preparative step. According to the X-ray diffraction data, both imino groups in the products have syn configuration with respect to the ring oxygen atom.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 6, 2005, pp. 903–909.Original Russian Text Copyright © 2005 by Trofimov, Mal’kina, Shemyakina, Kudyakova, Sokolyanskaya, Sinegovskaya, Albanov, Smirnov, Kazheva, Chekhlov, D’yachenko.     

Cyanoacetylene and Its Derivatives: XXVI. Hydrohalogenation of 4-Alkyl-4-hydroxy-2-alkynenitriles

The reaction of 4-alkyl-4-hydroxy-2-alkynenitriles with hydrogen halides (HCl and HI) in dioxane is accompanied by intramolecular cyclization with formation of 5,5-dialkyl-4-halo-2-imino-2,5-dihydrofuran hydrohalides. Treatment of the latter with K₂CO₃ in ethanol yields 5,5-dialkyl-4-halo-2-imino-2,5-dihydrofurans.     

Sulfurization of polymers. 5. Poly(6-methyl-5-sulfanylthieno[2,3-b]pyridine-4-thione), poly(thieno[2,3-b]azepine-4,5(6H)-dithione), and related structures from poly(2-methyl-5-vinylpyridine) and elemental sulfur

Poly(2-methyl-5-vinylpyridine) is sulfurized with elemental sulfur at 140—320 °C to release hydrogen sulfide and to give black lustrous powders (sulfur content up to 45%) possessing electric conductivity (6.4·10^–11—1.6·10^–7 S cm^–1), paramagnetism (spin concentration 6.2·10¹⁸—5.0·10¹⁹ sp g^–1, g = 2.0043—2.0046, H = 0.49—0.58 mT), and redox and complex-forming properties. Elemental analysis data, IR, ESR, and mass spectra, DSC and TGA data, electric conductivity, electrochemical activity and chemical properties (salt formation and complexation) of the materials synthesized correspond to cross-liked poly(6-methyl-5-sulfanylthieno[2,3-b]pyridine-4-thione), poly(thieno[2,3-b]azepine-4,5(6H)-dithione), and related structures.     

Sulfurization of polymers. 4. Poly(4,5,6,7-tetrathiono-4,5,6,7-tetrahydrobenzothiophene-2,3-diyl) and related structures based on polystyrene and elemental sulfur

Polystyrene was exhaustively sulfurized with elemental sulfur at 190--370 °C to liberate hydrogen sulfide and to form black lustrous powders (the sulfur content was up to 67%) possessing conductivity (10^–7--10^–6 S cm^–1 upon doping with I₂), paramagnetic properties ((3.4--13)·10¹⁹ sp g^–1, g = 2.0040--2.0046, H = 0.36--0.47 mT), and redox properties. The use of these polymers as active cathode materials in lithium batteries allows their repeated cycling at a specific discharge capacity of up to 330 mA h g^–1. The data of elemental analysis and differential scanning calorimetry, the IR and ESR spectra, the conductivities, and the character of electrochemical activity of the polymers synthesized are consistent with poly(4,5,6,7-tetrathiono-4,5,6,7-tetrahydrobenzothiophene-2,3-diyl) and related structures.