Polymere mit dem Zentralatom eines Makrocyclus in der Hauptkette, 1. Polykondensationsreaktionen mit Phthalocyaninsilicium- und Hemiporphyrazingermanium-Verbindungen

Dihydroxy(phthalocyanino)silicon ( 1b ) and dihydroxy(hemiporphyrazino)germanium ( 2b ) react with different monovalent alcohols to afford low-molecular bisalkoxy derivatives ( 4 and 5 ), and with thiophenol the phenylthio derivatives 11a and 11b , resp. With bivalent alcohols and phenols polymers of the structure 6 and 7 or 8a, b, 9a, b , and 10a, b , resp. are obtained. Dichloro(phthalocyanino)silicon ( 1a ) and dichloro(hemiporphyrazino)germanium ( 2a ) react also with phenol, resp. hydroquinone, to give low-molecular and polymeric phenoxy derivatives. The reaction of 1b and 2b with mono- and dibasic carboxylic acids leads to the corresponding esters. The IR-spectra of the prepared compounds are discussed. Thermogravimetric and semiconductive measurements (σ_298K ≈ 10^?7 to 10^?16Ω^?1cm^?1) are described.     

Polymere mit dem Zentralatom eines makrocyclus in der hauptkette, 2. Polykondensationsreaktionen mit Germaniumkomplexen des Phthalocyanins und meso-Tetraphenylporphins

Dihydroxy(phthalocyanino)germanium ( 1b ) and Dihydroxy(tetraphenylporphino)germanium ( 3b ) react with different monovalent alcohols to afford low-molecular bisalkoxyderivatives ( 1c – f and 3c – h ). With bivalent alcohols and phenols polymers of the structure 5 and 6 or 8a, 9a and 8b, 9b , resp., are obtained. Dichloro(phthalocyanino)germanium ( 1a ) and Dichlor(tetraphenylporphino)germanium ( 3a ) react also with phenol, resp. hydroquinone, to give low-molecular and polymeric phenoxy-derivatives. The reaction of 1b and 3b with mono- and dibasic carboxylic acids leads to the corresponding esters. Dehydration of 3b gives polymeric porphin 15 . The IR-spectra of the prepared compounds are discussed and compared with the analogous complexes of hemiporphyrazingermanium. Thermogravimetric and semiconductive measurements (σ_298K = 10^?10 – 10^?15Ω^?1 cm^?1) are described.     

Synthese und halbleitereigensehaften einiger komplexe und der aus ihnen hergestellten Polymeren. Teil 3. Polymere mit hemiporphyrazinartiger struktur

Polymers with a hemiporphyracine type structure were prepared by reacting some tetracyanocompounds like tetracyanobenzene and some sulfur containing complexes, which possess four cyanogroups, with 2.6-diamino-pyridine and p-phenylenediamine at elevated temperatures with the liberation of NH₃. The structure of the black, insoluble polymers was determined by elemental analysis and IR spectroscopy. The conductivities of the polymers varie between 2,3·10^?4 and 7,2·10^?14 Ohm^?1cm^?1. Autocondensation of 2.5-diaminodicyanothiophene, with and without CuCl₂, leads to black polymers having conductivities of about ? 7,1·10^?3 Ohm^?1cm^?1.     

Synthese und halbleitereigenschaften von hemiporphyrazinartigen polymeren mit tetrathiafulvalen-einheiten

Hemiporphyrazine type macroheterocycles with 2,2′-bi-1,3-dithiolylidene (tetrathiafulvalene) units in the polymeric chains ( 3a–e ) were obtained by reaction of 2,2′-bi-1,3-dithiolylidenetetracarbonitrile (tetracyanotetrathiafulvalene) ( 1 ) with several diamines ( 2a–e ). The black polymers were characterized by elemental analyses and IR spectra. Thermoanalytic measurements showed that decomposition starts without melting at temperatures > 300°C. The polymers were found to be polymeric organic semiconductors with activation energies of 0,6–1,4eV and electrical conductivities in the range from 10^?14 to 10^?10Ω^?1.cm^?1. In the case of the polymers 3a and 3b it was possible to obtain metal complexes ( 4a–b ) by substituting the two hydrogen atoms inside the macroheterocyclic rings. Depending on the metal atoms the electrical conductivities were enhanced up to two orders of magnitude.     

Proton‐Conducting Properties of Acid‐Doped Poly(glycidyl methacrylate)‐1,2,4‐Triazole Systems

1,2,4‐triazole‐functional PGMA polymers have been synthesized and their anhydrous proton‐conducting properties were investigated after doping with phosphoric acid and triflic acid. PGMA was prepared by solution polymerization and then modified with 1H‐1,2,4‐triazole (Tri) and 3‐amino‐1,2,4‐triazole (ATri). FT‐IR, ¹³C NMR and elemental analysis verify the high immobilization of the triazoles in the polymer chain. Phosphoric‐acid‐doped polymers showed lower T_g and higher proton conductivities. PGMA‐Tri 4 H₃PO₄ showed a maximum water‐free proton conductivity of approximately 10^?2 S · cm^?1 while that of PGMA‐ATri 2 H₃PO₄ was 10^?3 S · cm^?1. The structure and dynamics of the polymers were explored by ¹H MAS and ¹³C CP‐MAS solid‐state NMR.

     

Polymerisationsauslösung mit substituierten Ethanen, 1. Polymerisation von Methylmethacrylat mit 1,1,2,2-Tetraphenyl-1,2-diphenoxyethan

1,1,2,2-Tetraphenyl-1,2-diphenoxyethane (TPPA) initiates at 70°C the polymerization of methyl methacrylate. In the first period oligomers of the type 1 with two phenoxydiphenylmethyl end groups (P_n ≈ 1 – 20) are formed by primary radical termination. These telechelics are effective initiators of the further free radical polymerization of vinyl monomers.     

Mobile macromolecular carriers of ionic substances, 1. Transport of heavy metal ions by polymer analogues of teichoic acids

Bioanalogous organic polyphosphates (PP) and polymer ion-exchange membranes (IEM) were used to arrange a membrane system for the transportation of Zn(II), Mn(II), Cu(II), Co(II) and Ni(II) ions. The system consists of three membranes separating a feed and a strip solution with metal sulfates and sulfuric acid, respectively: Poly(trimethylene phosphate), α-hydroxy-ω-(2-ethylhexyl)poly(trimethylene phosphate), poly(1,2-glycerol phosphate) and poly(2,3-acetoxyglycerol phosphate) were used as ionic carriers for mimicking some transport functions of natural teichoic acids. These polyelectrolytes were found to facilitate the exchange-diffusion process of heavy metal ions and to exhibit fluxes in the range 3,5 · 10^?9 – 6 · 10^?9 mol M(II)/(cm² · s). The specific stationary fluxes typically change in the order J_Cu > J_Co > J_Ni > J_Mn > J_Zn. The observed transport preference is consistent with the affinity order of teichoic acids or the bacteria cell wall toward Cu(II), Mn(II) and Zn(II).     

Synthese und halbleitereigenschaften von phthalocyaninartigen polymeren mit Tetrathiafulvalen-Einheiten

4,5,4′,5′-Tetracyano-2,2′-bi-1,3-dithiolylidene (tetracyanotetrathiafulvalene) ( 1 ) was found to react with metal acetylacetonates ( 2a – m ) to give dark, insoluble, and infusible polymers 3a – m with phthalocyaninelike structure. The electrical conductivity of the polymers was investigated (σ_298K < 6·10^?5 Ω^?1 cm^?1), and a linear relationship between the logarithm of the electrical conductivity and the activation energy of the different polymers was found (compensation effect). Measurements of the thermoelectric power proved p-conduction.     

Polymerization of 1,3‐Pentadiene Initiated by Aluminium Trichloride in Nonpolar Solvent: Pseudo‐Control is Explained by Continuous Grafting

Summary: The cationic polymerization of 1,3‐pentadiene initiated by AlCl₃ was studied in nonpolar solvent. It was previously shown that at room temperature the active species were long‐lived and that the number‐average molar mass of the polymer chains was increasing with the polymerization yield. In order to explain this apparent control, the macromolecules were labeled with a transfer agent, triphenylamine (NPh₃). The latter binds to active species by electrophilic aromatic substitution. The labeling of the polymer chains indicated that at 20 °C the polymer chains mainly contained one NPh₃ molecule per macromolecule while the NPh₃ content was higher for the high molar mass chains due to a “grafting from” polymer transfer mechanism. Thus, the pseudo‐control was assigned to the branching reactions. The labeling process by NPh₃ also succeeded at ?10 °C. Whereas at ?10 °C a dialkylation of NPh₃ was observed, a trialkylation at 20 °C was obtained. The analysis of the polymer microstructure at both temperatures highlighted an interaction between the active centers and NPh₃. This paper also describes a process to synthesize tri‐arm stars polymers by cationic polymerization.

RI SEC chromatograms of soluble polymers synthesized at 20 °C in the presence of NPh₃ with increasing reaction times (r = [NPh₃]/[AlCl₃] = 1); (a) t = 0.25 h, (b) t = 0.5 h, (c) t = 1 h, (d) t = 2 h, (e) t = 18 h, (f) t = 48 h; [AlCl₃] = 2.3 × 10^?2 mol · L^?1, [1,3‐pentadiene] = 1.6 mol · L^?1, pentane.     

α,ω-dichloropoly(2-methylpropene) as an inifer: A modification to the Kennedy-Smith mechanism

Experimental details are given of attempts to enumerate the binary ionogenic equilibria (B.I.E.) of 1-chloro-1-methylethylbenzene ( 1 )/BCl₃, 1,4-bis(1-chloro-1-methylethyl)benzene ( 2 )/BCl₃ and 1,3,5-tris(1-chloro-1-methylethyl)benzene ( 3 )/BCl₃ in CH₂Cl₂. Due to chemical reaction (dimerisation or polymerisation) no experimental values for the B.I.E. constants could be obtained. A Born-Haber cycle is constructed to estimate the relative sequence of the overall B.I.E. constants. A similar treatment for 2-chloro-2methylpropane as a thermodynamic model for α,ω-dichloropoly(2-methylpropene) ( 4 ) suggests that the overall B.I.E. constant for these polymers is somewhat smaller than those for 1 and 2 but greater than that for 3 . Using 2 /BCl₃ as initiator for the polymerisation of 2-methylpropene (IB) it is shown, that the degree of polymerisation of 4 can be controlled within the limits 10 < DP < 100. It is shown that 4 can also act as an initiator for the polymerisation of IB, that these polymerisations involve only free ion propagation and, from a kinetic analysis of these polymerisations, that: (k)²/k = 12 1 · mol^?1 · s^?1, k = 1,2 · 10^?3 l · mol^?1 · s^?1, k [P] = 1,7 · 10^?3 s^?1, and k/(k K) = 102. The same analysis demonstrates that the self-ionisation of BCl₃ can be neglected in terms of any influence on the molar mass of the products. Experiments are also described which show that 2-chloro-2-methylpropane is not suitable as a substitute initiator for IB, but that 2-chloro-2,4,4-trimethylpentane is a useful model for 4 as an initiator for the polymerisation of IB.     

Soluble polystyrene derivatives of metal bis(3,4-dicarboxybenzoyl)phthalocyaninates: Synthesis,thermal analysis,and sensitivity towards toxic gases

Polystyrene-bound metal [2,9 or 2,10 (or 2,16 or 2,17) bis(3,4-dicarboxybenzoyl)]phthalocyaninates were synthesized by Friedel-Crafts reaction of polystyrene with the corresponding metal phthalocyaninates. Co(II) and Cu(II) [2,9 or 2,10 (or 2,16 or 2,17) bis(3,4-dicarboxybenzoyl)]-phthalocyaninate (PS-CodaPc and PS-CudaPc) contained 0,13 mmol · g^?1 (12,4 wt.-%) and 0,13 mmol · g^?1 (12,8 wt.-%) of CodaPc and CudaPc, respectively. They were soluble in N,N'-dimethylformamide, but only partially soluble in chloroform, tetrahydrofuran (THF), dimethyl sulfoxide, N-methyl-2-pyrrolidone, and pyridine. The THF extracts contained 0,12 mmol · g^?1 (11,4 wt.-%) and 0,18 mmol ? g^?1 (17,2 wt.-%) of PS-CodaPc and PS-CudaPc, respectively. The thermal stability of the polymers was studied using thermogravimetric and differential thermal analysis in nitrogen and synthetic air atmosphere. The contents of MdaPc(M: metal) in THF-extracted polymers calculated from the data of residue in thermogravimetric analysis are 0,12 mmol · g^?1 for PS-CodaPc and 0,19 mmol · g^?1 for PS-CudaPc. In addition, the sensitive properties of the polymers towards toxic gases were also investigated by quartz microbalance transducers. The results show that the quartz microbalance sensors coated with both polymers were sensitive to NO₂ and chlorinated hydrocarbons, i.e. chloroform and perchloroethylene. The sensitivity to NO₂ was 6,53 · 10^?7 m³ · mL^?1 · s^?1 for PS-CodaPc and 1,90 · 10^?6 m³ · mL^?1 · s^?1 for PS-CudaPc, and that to chloroform and perchloroethylene was 2,33 · 10^?8 and 4,60 · 10^?8 m³ · mL^?1 · s^?1, respectively, for PS-CodaPc and 4,79 · 10^?8 and 9,51 · 10^?7 m³ · mL^?1 · s^?1 for PS-CudaPc.     

Polymerization of Styrene Sulfonate Ethyl Ester by ATRP: Synthesis and Characterization of Macromonomers for Suzuki Polycondensation

Summary: Macromonomers from SSE were synthesized via ATRP with initiators carrying functional groups that are polymerizable by Suzuki polycondensation. The material obtained had a monomodal molar mass distribution with a polydispersity of 1.3–1.6. The reaction kinetics in bulk and in solution were monitored by in situ ¹H NMR spectroscopy. Rate constants and the activation energy for SSE polymerization were determined to be k = 5.5 · 10^?5 s^?1 (DMF, 60 °C), 6.6 · 10^?4 s^?1/1.4 · 10^?3 s^?1/4.8 · 10^?3 s^?1 (bulk, 45/60/75 °C), E_a = 60.1 kJ · mol^?1 (bulk). Hydrolysis yielded the corresponding macromonomers of poly(styrene sulfonic acid).

Monomer conversion for different reaction temperatures and exponential fit to the data for the SSE polymerization in bulk.     

Über Polyarylenalkenylene und Polyheteroarylenalkenylene, 9. Synthesen und Charakterisierung von Poly(5-methylthiazolo-[4,5-f] benzthiazolium-2,6-diylvinylenarylenvinylen)en und einigen Modellverbindungen

Starting from 2,3,6-trimethylthiazolo[4,5-f] benzothiazolium perchlorate ( 2b ) some poly(5-methylthiazolo[4,5-f] benzothiazolium-2,6-diylvinylenarylenevinylene)s ( 11a–c ) and some corresponding model compounds ( 10a–c ) were prepared via Knoevenagel condensation with mono-and dialdehydes ( 4 and 6 ) of the benzene and thiophene series. Additional series of model compounds ( 5a–c, 7a–c, 8a–f , and 9a–f ) were obtained from 2,3,6-trimethylthiazolo[4,5-f]benzothiazolium iodide ( 2a ) or 2,3-dimethylbenzothiazolium iodide ( 3a ), respectively, or from the perchlorates ( 2b and 3b ) submitted to the same reaction with mono-and dialdehydes. The structure of these model compounds and polymers was confirmed by elemental analyses, IR and electronic spectra. The model compounds are also characterized by their mass spectra, and in the case of sufficient solubility by ¹H NMR spectroscopy too. The electrical conductivities of all compounds and polymers and the thermooxidative degradation of the polymers were investigated.     

Hyperbranched Polyalkoxysiloxanes via AB3‐Type Monomers

We have synthesized polyethoxysiloxanes starting from the AB₃‐type monomers triethoxysilanol and acetoxytriethoxysilane. The polymers are liquid and soluble in organic solvents. ²⁹Si NMR spectroscopy and MALDI‐ToF mass spectrometry analyses show that the polymers have a hyperbranched structure with additional internal cyclization. ²⁹Si NMR spectroscopy indicates that the polymer synthesized from acetoxytriethoxysilane is less branched than the polymer synthesized from triethoxysilanol. Analysis of the molar mass and mass distribution of the polymers via size exclusion chromatography (calibrated via MALDI‐ToF MS and viscosimetry) yields a molar mass of M _n ≈ 2 kg · mol^?1 and M _w ≈ 8 kg · mol^?1 for polymers synthesized from triethoxysilanol. The molar mass of the polymers synthesized from acetoxytriethoxysilane can be controlled by variation of the polymerization time in the range of M _n ≈ 1.8–12 kg · mol^?1 and M _w ≈ 2.1–2 200 kg · mol^?1.

Photograph of a vial containing polyethoxysiloxane obtained from triethoxysilanol and a schematic drawing of the proposed molecular structure of the polymer.     

Migration Phenomena in Methacrylic Esters and Polymers Derived from Glycerol

Isomerization reactions were analyzed in methacrylic monomers and polymers derived from glycerol. It was observed that this kind of reactions takes place in similar way on both 1,3‐dihydroxypropyl methacrylate and poly(1,3‐dihydroxypropyl methacrylate). This polymer only could be synthesized in pure state by acid hydrolysis from precursor polymers such as poly(cis‐(2‐phenyl‐1,3‐dioxan‐5‐yl) methacrylate) (PCPDM) or poly(trans‐(2‐phenyl‐1,3‐dioxan‐5‐yl) methacrylate) (PTPDM), which were prepared by radical polymerization of the corresponding monomers. The isomerization reactions were analyzed qualitatively and quantitatively by means of high resolution ¹H NMR spectroscopy. It was shown that, as a consequence of migration of the ester group in the methacrylic residue, the 1,3‐dihydroxy units in poly(1,3GM) evolved to 2,3‐dihydroxy units, giving a copolymer poly(1,3‐dihydroxypropyl methacrylate‐est‐2,3‐dihydroxypropyl methacrylate). The copolymer is very rich in the 2,3‐dihydroxy units that are thermodynamically more favored by around 900 cal · mol⁻¹ at room temperature.

¹³C NMR spectrum of a copolymer of 1,3GM (90%) and 2,3GM (10%) in D₂O solution.     

Facile Synthesis of Nanoporous Hydroquinone/Catechol Formaldehyde Resins and their Highly Selective,Efficient and Regenerate Reactive Adsorption for Gold Ions

We present a new type of nanoporous hydroquinone/catechol formaldehyde resin synthesized by a one‐pot route, with a surface area of up to 1 112 m² · g^?1. The resins show highly efficient reactive adsorption for silver/gold (silver adsorbance up to 2.43 g · g^?1) and excellent selectivity for gold (K_d is as high as 1 914 090 mL · g^?1). The first‐used resins can be regenerated with NaHSO₃, and the gold capacities of the recycled PCFR and PHFR reach 44 and 78% of their first loading capacities, respectively.

     

Kinetics of the anionic polymerization of ϵ-caprolactone with K+ · (dibenzo-18-crown-6 ether) counterion. Propagation via macroions and macroion pairs

Following our earlier work on the polymerization of lactones involving crowned cations, kinetics of the anionic polymerization of ?-caprolactone (?CL) with K⁺ · (dibenzo-18-crown-6 ether) (K⁺DB18C6) counterion was studied calorimetrically in THF solution in the temperature range from 0 to 20°C. Dissociation constants of CH₃(CH₂)₅O^?K⁺DB18C6, modelling the active centers, were determined conductometrically: K_D (20°C) = 7,7 · 10^?5 mol · dm^?3, ΔH = 9,3 ± 0,2 kJ · mol^?1, ΔS = ?47 ± 2J · mol^?1 · K^?1. From kinetic measurements and from measurements of the dissociation constant of CH₃(CH₂)₅O^? K⁺DB18C6, rate constants of propagation via macroions and via macroion pairs were determined. Activation parameters for propagation via these species are equal to: ΔH = 39,2 ± 0,2 kJ · mol^?1, ΔS = ?63 ± 1 J · mol^?1 · K^?1, ΔH = 13,7 ± 0,1 kJ · mol^?1, ΔS = ?185 ± 2 J · mol^?1 · K^?1. At 20°C, k = 3,50 · 10² dm³ · mol^?1 · s^?1 and k = 5,2 dm³ · mol^?1 · s^?1. Due to the large difference of ΔH^≠ for propagation via macroions and macroion pairs (vide supra), the isokinetic point (k = k) would appear at ?65°C.     

Novel Metal‐Containing Polyurethane Elastomers Prepared Using Tetradentate Schiff Base Metal Complexes

Summary: A series of divalent metal (Co²⁺, Ni²⁺, Cu²⁺)‐incorporated tetradentate Schiff base complexes of the generic name 1,2‐bis[{4‐(2‐hydroxy)ethoxy‐2‐hydroxyphenyl}methyl ketimino]ethane‐metal(II) (BHEHPMKE‐M)—metal‐containing dihydroxy monomers—were synthesized and characterized by UV‐visible, FT‐IR, MS, and atomic absorption spectroscopies and elemental analysis. Structure of one of the monomers was also confirmed by single‐crystal X‐ray diffraction technique. Several metal‐containing polyurethanes were prepared using these dihydroxy compounds and 1,4‐butanediol as chain extenders for prepolymers based on poly(oxytetramethylene) glycol‐2000 (PTMG‐2000) and 4,4′‐methylene bis(phenyl isocyanate) (MDI). The amount of metal‐containing monomer was varied from 0 to 1 equivalent to find the influence of the metal‐incorporated tetradentate Schiff base segment on thermal and mechanical properties of polyurethanes. The properties of metal‐containing polyurethanes were compared with those prepared using 1,4‐butanediol and 1,2‐bis[{4‐(2‐hydroxy)ethoxy phenyl}methyl ketimino]ethane—a diol without metal—as chain extenders. The polymers were characterized by FT‐IR, GPC, DSC, TGA, viscosity, and solubility measurements. The glass transition temperature (T_g) of the polyurethane prepared from the Schiff base diol (without metal) was found to increase when used alone as chain extender. Thermal and mechanical properties of polyurethanes were also found to improve markedly by the introduction of metal‐incorporated tetradentate Schiff base moiety into the polymer chain. The viscosity of the metal‐containing polyurethane decreased abruptly upon increasing the metal content.

A series of polyurethanes derived from novel divalent metal (Co²⁺, Ni²⁺, Cu²⁺)‐incorporated tetradentate Schiff base complexes.     

Reverse Atom Transfer Radical Polymerization of Methyl Methacrylate using a New Catalyst,Copper(II) N,N′‐Butyldithiocarbamate

Summary: The homogeneous bulk reverse ATRP using AIBN/Cu(SC(S)N(C₄H₉)₂)₂/bpy as the initiating system has been successfully carried out for methyl methacrylate. Well‐controlled polymerizations with low polydispersities ( = 1.10–1.30) have been achieved. The revised number‐average molecular weights ( 's) increased linearly with monomer conversion and were close to the values. The polymerization rate followed the first‐order kinetics in monomer, while it is about 2.0 order in initiator concentration and 1.15 order in Cu(II) concentration. The k values for the homogeneous bulk reverse ATRP of MMA initiated by AIBN/Cu(SC(S)N(C₄H₉)₂)₂/bpy (1:2:6) at 80, 90, 100 and 110 °C were 0.402 × 10^?4, 1.021 × 10^?4, 2.952 × 10^?4, and 3.687 × 10^?4 (s^?1), respectively. On the basis of the Arrhenius plot, the apparent activation energy was calculated to be ΔE = 87.1 kJ/mol. The obtained PMMA was functionalized with an ultraviolet light sensitive ω‐SC(S)N(C₄H₉)₂ group characterized by means of ¹H NMR spectroscopy, and which was also proved by its chain extension with fresh MMA under UV‐light irradiation at room temperature. A polymerization mechanism for this novel initiation system is proposed.

Dependence of and on the monomer conversion for the homogeneous bulk reverse ATRP of MMA at different concentration of catalyst.     

Electrochemical polymerization of derivatives from N-methylpyrrole and thiophene to heteroarylenevinylene polymers

The heteroaryl- and heteroarylenevinylene compounds 1, 2, 3 , and 4 were investigated by means of cyclic voltammetry and submitted to oxidative electropolymerization under galvanostatic conditions; the products obtained were further characterized by means of elemental analysis, optical absorption spectroscopy and conductivity measurements. (E)-1,2-bis(N-methyl-2-pyrrolyl)ethylene ( 1 ), 2,5-bis[(E)-2-(N-methyl-2-pyrrolyl)vinyl]thiophene ( 2 ) and N-methyl2,5-bis[(E)-2-(N-methyl-2-pyrrolyl)vinyl]pyrrole ( 3 ) gave brittle to spongy films on electropolymerization with perchlorate as the counterion balancing the positive charge on the polymer backbone units. The d. c. conductivity of all three polymers (as perchlorates) was of the order of 10^?3 Ω^?1·cm^?1. N-methyl-2,5-bis[(E)-2-(2-thienyl)vinyl]pyrrole ( 4 ) did not give a solid polymer.