M. V. Markova

2-Arylazo-1 -vinylpyrroles : Free-Radical Polymerization and Copolymerization

2-Arylazo-1-vinylpyrroles (a new group of azo dyes of the pyrrole series) are polymerized under heating (80°C) without initiators and in the presence of AIBN to form intensely colored paramagnetic and conducting polymers with a yield of 92%. By the example of the thermal copolymerization with 1-vinylpyrrolidone, it has been shown that 2-arylazo-1-vinylpyrroles may simultaneously play the roles of initiators and comonomers.

Copolymerization of vinyl chloride with 1-vinyl-4,5,6,7-tetrahydroindole and 2-methyl-5-vinylpyridine

The radical copolymerization of vinyl chloride with 2-methyl-5-vinylpyridine and 1-vinyl-4,5,6,7-tetrahydroindole is accompanied by dehydrochlorination. In the vinyl chloride-2-methyl-5-vinylpyridine system, the evolved hydrogen chloride interacts with a pyridine hydrogen atom to give charged units of a heterocycle. In the vinyl chloride-1-vinyl-4,5,6,7-tetrahydroindole system, the hydrogen chloride being formed initiates the cationic dimerization of a nitrogen-containing monomer. The synthesized copolymers based on vinyl chloride surpass the commercial poly(vinyl chloride) in terms of thermal stability and solubility in organic solvents.

Dimerization of 1-vinyl-4,5,6,7-tetrahydroindole in the presence of acids

In the presence of Bronsted and Lewis acids, I-vinyl-4,5,6,7-tetrahydroindole is transformed into its dimes, 1-vinyl-2-[1-(4,5,6,7-tetrahydroindolyl)ethyl]-4,5,6,7-tetrahydroindole, and polymers containing units of the dimer and segments of oxidized tetrahydroindole cycles.

Polymerization of 1,4-bis[2-( N -vinyl)pyrrolyl]benzene

Polymers of 1,4-bis[2-(N-vinyl)pyrrolyl]benzene with free N-vinyl groups in side chains are synthesized in the presence of AIBN (2–5 wt %, 70°C) with a yield of up to 34% and a molecular mass of up to 11.5 × 103. In the presence of cationic catalysts (Me3SiCl, the LiBF4-dimethoxyethane system, and BF3 · OEt2), 1,4-bis[2-(N-vinyl)pyrrolyl]benzene gives macromolecules with alternating 1,2-pyrrolene and ethylidene units in the backbone with yields of 80, 44, and 33%, respectively. The polymers demonstrate paramagnetic and luminescent properties.

Expedient Strategy for the Synthesis of 5-Acylethynylpyrrole-2-carbaldehydes

Abstract 5-Acylethynylpyrrole-2-carbaldehydes have been synthesized from the protected pyrrole-2-carbaldehydes by their transition-metal-free topochemical mechanoactivated ethynylation with acylbromoacetylenes in a solid Al2O3 medium (room temperature, 6 h, 41–54% yields). GRAPHICAL ABSTRACT

Polymerization of N-vinylpyrroles: Recent achievements

The data on the polymerization of N-vinylpyrroles published for the most part during the past decade are systematized and summarized. Radical, cationic, and anionic polymerization of the mentioned monomers, which became easily accessible owing to the discovery and systematic development of their direct one-step synthesis from ketoximes and acetylene in the superbasic catalytic system KOH/DMSO (the Trofimov reaction), are discussed. Special attention is given to the physicochemical properties of the polymers (conductivity, paramagnetism, photosensitivity, and optical characteristics).

Composite proton-conducting membranes based on poly(ethylene glycol vinyl glycidyl ether)

Composite proton-conducting membranes in the form of interpolymer films are prepared in an aqueous medium from sulfo-acid-modified poly(ethylene glycol vinyl glycidyl ether) and poly(vinyl alcohol). The initial poly(hydroxysulfo acid) is synthesized through the radical polymerization of ethylene glycol vinyl glycidyl ether followed by modification with sodium sulfite via epoxy groups and treatment with a cationite in the H form. The proton-conducting membranes feature improved thermal stability (200–250°C), a breaking strength of 1.0–8.9 MPa, elasticity (a relative elongation at break of 1.0–8.2%), chemical resistance, and specific proton conductivity attaining 10−1 S/cm after doping with orthophosphoric acid.

Free-radical cooligomerization of N -vinyl-4,5,6,7-tetrahydroindole with butyl vinyl ether

Oligo(N-vinyl-4,5,6,7-tetrahydroindole-co-butyl vinyl ethers) have been synthesized through free-radical cooligomerization with a yield of 84%. The copolymers are readily soluble in organic solvents (benzene, 1,4-dioxane, chloroform, and tetrahydrofuran), stable up to 380–400°C, and paramagnetic. (The concentration of paramagnetic centers is 1014 spin/g.) In addition, the copolymers exhibit the properties of organic semiconductors. (After being doped with iodine, σ = 1.1 × 10−7 S/cm.) The analysis of the 1H and 13C NMR spectra has shown that the oligomerization reaction is complicated by intramolecular cyclization involving carbon atoms located at the 2-position of pyrrole rings.

Copolymerization of N-vinylpyrrole-2-carbaldehydes with styrene, N-vinylpyrrolidone, and ethylene glycol vinyl glycidyl ether

Polyfunctional reactive copolymers of N-vinylpyrrole-2-carbaldehydes with styrene, N-vinylpyrrolidone, and ethylene glycol vinyl glycidyl ether are synthesized in the presence of AIBN (2 wt %, 80°C, 50 h) with a yield of up to 98% and a molecular mass of up to 4800. The copolymers show paramagnetic behavior (N = 2.0 × 1015−2.0 × 1017 g−1) and possess the properties of organic semiconductors (σ = 0.9 × 10−11–2.8 × 10−7 S/cm after doping with I2).

Nanoporous Crosslinked Macrocyclic Polyethers Based on Diethylene Glycol Divinyl Ether and Their Superbase Complexes with KOH

Nanoporous (11–12 nm) crosslinked macrocyclic polyethers with vinyloxy and hydroxyl groups have been synthesized by the free-radical polymerization of diethylene glycol divinyl ether (AIBN, 80°C, i-octane), followed by acidic hydrolysis. It has been shown that the polymers react with KOH to form insoluble superbase complexes and alcoholates capable of catalyzing vinylation of ethylene glycol by acetylene.