Polymers containing phenylquinoxaline rings

The synthesis and properties of poly(phenylquinoxalines) containing hexafluoroisopropylidene or silylene units in the backbone are described. The polymers have been prepared by polycondensation of aromatic diamines containing preformed phenylquinoxaline rings with a dianhydride or diacid chlorides containing hexafluoroisopropylidene groups, or with a dianhydride or diacid chlorides containing silylene units. The solubility, thermal stability, film forming ability, and electric insulating, mechanical, and electroluminescent properties of the thin films are discussed and compared with those of related heterocyclic polymers. Potential applications of poly(phenylquinoxalines) are outlined.Based on the report presented at the International Conference Modern Trends in Organoelement and Polymer Chemistry dedicated to the 50th anniversary of the A. N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences (Moscow, May 30–June 4, 2004).Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1739–1748, September, 2004.     

Diels-Alder polymers. III. Polymers containing phenylated phenylene units

The Diels-Alder reaction of biscyclopentadieneones with diacetylenes produces colorless, soluble, phenylated polyphenylenes of high molecular weight (M?_n ? 40,000) in nearly quantitative conversions. The polymers are noncrystalline, form clear films, and are stable in air to 550°C. Under nitrogen, the polymers lost approximately half the phenyl groups attached to the phenylene main chain to give brown-black insoluble polyphenylenes of very low crystallinity.     

Rigid-ladder polymers: Polymers containing anthraquinone recurring units

In an attempt to synthesize some processable ladder or partial ladder polymers containing anthraquinone recurring units, leucoquinalizarin was treated with 3,3′-diaminobenzidine. This polymer, which was a black powdery material, was slightly soluble in concentrated sulfuric acid and dimethylsulfoxide. Also, 1,5-diamino-2,6-dimercaptoanthraquinone was condensed with 2,5-dichloro-p-benzoquinone in pyridine to give a black powdery polymer. This was only partially soluble in concentrated sulfuric acid, but could be solubilized in alkali by reduction with sodium dithionite.     

Stability of polyhedral borane anions and carboranes

Polyhedral borane anions and carboranes that can be constructed formally from the interaction of rings and caps will be stable with six interstitial electrons. Interstitial electron count is obtained by summing the number of π electrons of the ring and the electrons of the caps involved in ring cap binding. Thus B₇H₇ ⁻² (D_5h) has 6 interstitial electrons (none from the B₅H₅ ring, two each from the twobh caps and two negative charge),mndo calculations on isoelectronic pyramidal molecules B₆H₆ ⁻⁴ (C_5v), B₅H₅CH⁻³ (C_5v), B₅H₅ ⁻⁴ (C_4v), B₄H₄CH⁻³ (C_4v), B₄H₄ ⁻⁴ (T _d) and B₃H₃CH⁻³ (C_3v) suggests a criterion based on the out-of-plane bendings of the ring B-H bonds to select the best combination of borocycles and BH or CH caps. Three-membered borocycle prefers CH cap, five-membered borocycle prefers BH cap. The preference of four-membered ring for BH or CH cap is not as pronounced. The extra stability of B₁₂H₁₂ ⁻² arises from the geometry of the icosahedron. The relative stabilities ofnido andcloso carboranes follow from these rules.     

Angular polycyclic thiophenes containing two thiophene rings. I

We describe the synthesis of thieno[2,3-c]dibenzothiophene ( 6 ), thieno[3,2-c]dibenzothiophene ( 10 ), thieno-[3,2-a]dibenzothiophene ( 14 ), thieno[2,3-a]dibenzothiophene ( 16 ), benzo[1,2-b:4,3-b]bisbenzo[b]thiophene ( 18 ), benzo[1,2--6:3,4-b]bisbenzo[b]thiophene ( 20 ), benzo[2,1--6:3,4-b]bisbenzo[b]thiophene ( 22 ), benzo[1,2-b:3,4-g]bisbenzo[b]thiophene ( 27 ), benzo[1,2-b:4,3-e]bisbenzo[b]thiophene ( 29 ), benzo[2,1--6:3,4-g]bisbenzo[b]thiophene ( 36 ), benzo[2,1--6:4,3-e]bisbenzo[b]thiophene ( 38 ), benzo[1,2--6:4,3-g]bisbenzo[b]thiophene ( 41 ), benzo[1,2-b:4,5-g]bisbenzo[b]thiophene ( 42 ), benzo[1,2-b:3,4-e]bisbenzo[b]thiophene ( 44 ) and benzo-[1,2-b:5,4-e]bisbenzo[b]thiophene ( 45 ).     

Low surface energy polymers and surface active block polymers. I. t-butylphenyl containing polymers

Two new monomers in the 2-oxazoline series were synthesized and polymerized. These were 2-[4-(t-butyl)phenyl]-2-oxazoline ( I ) and 2-[(3-(3,5-di-t-butyl)phenoxy)propyl]-2-oxazoline ( II ). The polymer from I crystallized readily during bulk polymerization and showed T_m at 592 K (319°C). After annealing, the polymer showed a critical surface tension of 23.2 dyn/cm. Polymer from II was amorphous; hence, annealing showed little effect on contact angles. Block polymers were made with I (Xn = 10) and ethyl oxazoline (Xn = 6,20,60). Very sharp molecular weight distributions were obtained. All samples crystallized when annealed. The block polymer was an effective emulsifier for emulsion polymerization of butyl acrylate at 0.1%.     

Heat-resistant polymers containing bipyridyl units. I. Polyimides

Polyimides containing bipyridyl units were synthesized. The bipyridyl units were successfully incorporated by polymerization of various bipyridyl diamines with aromatic tetracarboxylic acid dianhydrides. The resulting polyamic acids had inherent viscosities in the range 0.07 to 2.26, and they were converted to the polyimides by thermal cyclization. The polyimides containing the bipyridyl units exhibited varying degrees of solubility in dimethylacetamide and m-cresol and were found to be very soluble in dichloroacetic acid.     

Condensation polymers containing silicon and germanium in the main chain

Poly(carbonates), poly(thiocarbonates) and poly(esteres) containing silicon and/or germanium in the main chain were obtained under phase transfer conditions. Polymers were synthesized in a biphasic system NaOH/CH₂Cl₂ at 20°C using several phase transfer catalysts, and characterized by IR and ¹H and ¹³C NMR. The results were evaluated by the yields and the inherent viscosity values. The process was effective observing an increase of both parameters in comparison with the essays without catalyst. The increases depended of the nature of the polymer and the catalyst. In poly(ester) synthesis there was an increase of these parameters when the NaOH concentration was increased due to a salting out effect of the diphenolate from the aqueous phase to the organic one. Also poly(amides) containing silicon or germanium were synthesized by solution polymerization.     

Polymers containing anthraquinone units: Benzimidazole and benzothiazole polymers

In an attempt to synthesize soluble polymers, diphenyl 1,5-anthraquinonedicarboxylate was treated with 3,3′-dimercaptobenzidine and 3,3′-diaminobenzidine under various conditions. Although the ester reacted readily, side reactions prevented the formation of high molecular weight compounds. It was thought that at the elevated temperatures required for reaction, the quinone group was involved in a type of Schiff's base formation. The thermal stability of the polymers was evaluated. Model compounds were prepared and their absorption spectra were compared with those of the polymers. It was observed that 1,5-anthraquinonebibenzimidazole-2 formed a stable product with acetic acid. Some of the polymers could be solubilized by reduction with sodium dithionite in alkali, but no useful fibers were produced from these solutions.     

Heat-resistant polymers containing thianthrene analogs units. I. Polyimides

Polyimides that contained thianthrene and dibenzo-p-dioxins units were synthesized. The tricyclic fused rings were successfully incorporated by polymerizing the diamines of the units with aromatic tetracarboxylic dianhydrides. The resulting polyamic acids were converted to polyimides by thermal cyclodehydration. The influence of the tricyclic units on the properties of the polyimides has been investigated. Polyimides that contained dibenzo-p-dioxins (ODP) exhibited sufficient thermal stability but were insoluble even in concentrated sulfuric acid. The introduction of a methyl group did not produce an appreciable increase in solubility. Thianthrene polyimides were considerably less stable than the equivalent polymers derived from open-chain diamine, 4,4′-diaminodiphenyl sulfide but were partly soluble in acid solvents. The results are discussed in terms of packing the polymer molecules.     

Preparation of phosphorus-containing polymers—XVII. Preparation of polyamides containing phenoxaphosphine rings

New phenoxaphosphine-containing polyamides were prepared from 2,8-dichloroformyl-10-phenylphenoxaphosphine 10-oxide (III) and aromatic diamines in DMA by low-temperature solution polycondensation in the presence of triethylamine as acid acceptor. (III) was synthesized by the chlorination of 2,8-dicarboxy-10-phenylphenoxaphosphine 10-oxide derived from 2,8-dimethyl-10-phenylphenoxaphosphine 10-oxide by pyridine-permanganate oxidation. The resulting polyamides had a reduced viscosity of 0.14–0.40 dl/g in DMA or conc. H₂SO₄ at 30°. They were soluble in conc. H₂SO₄ and some of them dissolved in DMA, DMF and DMSO, but all were insoluble in benzene and formic acid, etc. They had good thermal stability, hardly degrading until a temperature of about 400° was reached; they showed resistance to ignition.     

Polymers containing hydrogen bonding rings. Synthesis and thermal properties of poly(enamine-ketones)

The synthetic route to poly(enamine-ketones) by vinylogous nucleophilic substitution of aromatic bis(1,3-diketones) with aromatic and aliphatic diamines is described. The preparation of aromatic bis(1,3-diketones), their polymerization, and thermal properties of the polymers are presented in detail. The polymers exhibited anisotropic melts and representative model compounds were shown to be thermotropic liquid crystals.     

Structure and physical properties of glow discharge polymers. I. Polymers from hydrocarbons

The polymers deposited from the vapors of pentane, ethylene, butadiene, benzene, styrene, and naphthalene subjected to glow discharge have been analyzed by infrared absorption techniques. The reaction products show unsaturation, hydrogenation, and branching in the polymer chains. Aromaticity is present only in polymers from aromatic monomers.     

Dielectric relaxations in polymers containing dioxacyclohexane rings by thermostimulated depolarization currents

The dielectric activity of poly{5-[(methacryloxy)methyl]-5-ethyl-1,3-dioxacyclohexane} (PMAMED) and poly[(5-methacryloxy)-1,3-dioxacyclohexane] (PMAD) in the glassy region and in the glass-rubber transition is investigated by using global and partial thermostimulated discharge current (TSDC) techniques. The global TSDC curve for each polymer displays an ostensible β absorption in the glassy region followed in increasing order of temperature for a prominent α glass rubber relaxation. Partial depolarisation curves show in detail the regions of the glassy state in which more dielectric activity occurs. The TSDC curves for PMAMED are compared with those of its acrylate homologous, poly{5-[(acryloxy)methyl]-5-ethyl-1,3-dioxacyclohexane} (PAMED), finding that the methyl group in the former polymer only hinders long range micro-Brownian motions in the chains, thus shifting the glass-rubber relaxation to higher temperatures, without affecting in a significant way molecular motions in the glassy region. Small changes in the neighbourhood of the 1,3-dioxacyclohexane ring, such as suppression of a methylene group or replacement of the equatorial hydrogen in position 2 of the ring for a phenyl group, depresses the dielectric activity and shifts the β absorptions to lower temperatures. The interconversion between TSDC and a.c. dielectric results in the glassy region is discussed.     

Properties of Heterocyclic Condensation Polymers

Abstract

Basic questions concerning heterocyclic polymers are reviewed. Initial investigations on the heterocyclic polymer BBB prepared from napthalene-1,4,5,8 tetracarboxylic acid and 3,3′-diaminobenzidine are described. These include infrared absorption studies of the structure of the polymer, fractionation of the polymer by exclusion chromatography on a porous substrate, and light scattering and dilute solution viscometry on fractions of the polymer dissolved in a strong acid. These data are interpreted to conclude that: (1) in dilute solutions BBB behaves as a “flexible coil” macromolecule, with perhaps relatively free rotation about the single bond connecting the long, inflexible, nearly planar repeat units; (2) a sufficient amount of interchain complex formation occurs in the solid state to give the linear, noncrystalline polymer some of the physical properties of a highly cross-linked network polymer.     

Biodegradable polymers based on renewable resources. II. Synthesis and biodegradability of polyesters containing furan rings

A series of polyesters were synthesized by the bulk polycondensations of the respective combinations of two difuranic diesters, i.e., bis(5-(methoxycarbonyl)-2-furyl)methane ( 4a ) and 1,1-bis(5-(methoxycarbonyl)-2-furyl)ethane ( 4b ), with two 1,4 : 3,6-dianhydrohexitols [1,4 : 3,6-dianhydro-D -glucitol ( 1 ) and 1,4 : 3,6-dianhydro-D -mannitol ( 2 )], four aliphatic diols, and three oligo(ethylene glycol)s. The polycondensations were carried out at 220–230°C in the presence of titanium isopropoxide as a catalyst, giving polyesters having number average molecular weight up to 2.4 × 10⁴. These polyesters are soluble in a variety of solvents including chlorinated hydrocarbons, 1,4-dioxane, dimethyl sulfoxide, dimethylformamide, and sulfolane. Soil-burial tests along with enzymatic degradation experiments showed that these polyesters are potentially biodegradable. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2729–2737, 1997     

Electrochemical synthesis of conducting polymers from oligomers containing thiophene and furan rings

Oligomers containing 2,5-thienylene and 2,5-furanylene units were synthesized by NiCl₂ (dppp) (dppp = Ph₂PCH₂CH₂CH₂PPh₂) coupling of Grignard compounds with the appropriate bromothiophene or bromofuran; UV and electrochemical data are given and discussed in terms of number and kind of heterolene units in the oligomeric species.