Synthesis and properties of oxygen‐, methylene‐, and alkylene‐bridged poly(dithiafulvene)s

Polymerization by cycloaddition between aldothioketene and its alkynethiol tautomer (derived in situ from a diyne) leading to the formation of dithiafulvene unit‐linked polymers has been studied. Two aromatic diynes [bis(4‐ethynyldiphenyl)methane ( 1a ) and 4,4′‐diethynyldiphenyl ether) ( 1b )] were used as starting materials with the aim of obtaining non‐π‐conjugated methylene‐ and oxygen‐bridged aromatic poly(dithiafulvene)s. The poly(dithiafulvene) derived from bis(4‐ethynyldiphenyl)methane can be considered as an interesting precursor to a small band‐gap polymer having alternating aromatic and quinonoid moieties. Further, two aliphatic diynes [1,7‐octadiyne ( 3a ) and 1,9‐decadiyne ( 3b )] were subjected to cycloaddition polymerization to obtain aliphatic poly(dithiafulvene)s containing localized electron‐rich dithiafulvene units. The polymers obtained were characterized by IR, ¹H NMR, gel permeation chromatography, and cyclic voltammetry. The electron‐donating property of the polymers was evident from the charge‐transfer (CT) complex formation with an electron acceptor 7,7,8,8‐teracyanoquinodimethane. The CT complexes were characterized by IR, ¹H NMR, and ultraviolet–visible spectroscopies. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3593–3603, 2001     

Vapor phase deposition of polybenzoxazoles

Vapor phase deposition was carried out on multifunctional aliphatic and aromatic benzoxazoles to yield powdered samples of poly(dimethylenebenzoxazoles). Representative aliphatic and aromatic poly(dimethylenebenzoxazoles) were also synthesized through solution methods using 4-amino-3-hydroxyhydrocinnamic acid and 2-(4-(bromomethyl)phenyl)-6-(bromomethyl)benzoxazole, respectively, as monomers. Both aromatic and aliphatic polybenzoxazoles containing  CH₂CH₂ units in the polymer backbone displayed catastrophic weight loss over a very narrow temperature range. This is in contrast with other polybenzoxazoles which show a gradual weight loss over 500–1000°C. Vapor phase deposition carried out under vacuum on the polymers gave similar polymers in the collection zone suggesting the catastrophic weight loss is attributed to thermal depolymerization of the polymer through a diradical intermediate similar to the thermolysis and polymerization of [2.2]paracyclophane. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1317–1328, 1998     

Preparation and structure/property relationships of polyesters containing conjugated diacetylene groups

A series of novel polyesters containing conjugated diacetylenes (DA‐polyesters) were prepared from various diacetylene diols with/without methyl side groups and isomers of aromatic acid chlorides via an interfacial condensation. A fully aliphatic DA‐polyester was also prepared for comparison. All synthesised DA‐polyesters are soluble in m‐cresol, and the intrinsic viscosities were measured. In addition, compact and coherent films and sheets can be obtained from some of the polymers via solution or melt casting. The structure, morphology, and properties were characterized using spectroscopic methods, including FTIR, Raman, and WAXD and thermal analysis including TGA, DSC techniques. DMA was carried out on the solution‐cast thin films and melt‐processed samples. Close correlation was found between the structure and properties in these DA‐polyesters. In particular, through analysis using isothermal DSC and Raman spectroscopy, the solid‐state reactivity of the diacetylene groups in these polyesters was found related to the interchain spacings, which are, in turn, controlled by the molecular structure of the polymers. Results have shown that the aliphatic DA‐polyester behaves very differently compared to the aromatic ones. Distinct differences were also observed among meta‐ and para‐disubstituted isomers of the DA‐polyesters. Furthermore, the introduction of methyl side groups has dramatically affected the thermal and thermal mechanical behavior by altering the interchain spacing of the polymers. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 965–974, 1999     

Catalytic [2 + 2 + 2] cycloaddition polymerization of diyne–nitrile monomers in the presence of CoCl2‐6H2O/diphosphine/Zn

Cobalt‐catalyzed [2 + 2 + 2] cocycloaddition reaction of 1,6‐diynes and nitriles to generate substituted pyridines has been applied to the polymerization of diyne–nitrile monomers, the reaction of which proceeded smoothly in a step‐growth fashion to provide linear polymers comprising pyridine structures in the main chain. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 345–351     

Catalyzed Addition of Aldehydes to Activated Double Bonds—A New Synthetic Approach

In the presence of cyanide ions as catalyst, aromatic and heterocyclic aldehydes can be smoothly added to α,β-unsaturated ketones, esters, and nitriles in aprotic solvents to form γ-diketones, 4-oxo carboxylic esters, and 4-oxo nitriles. Thiazolium salts in the presence of bases are also suitable catalysts; they permit not only addition of aromatic and heterocyclic aldehydes but also the addition of aliphatic aldehydes.     

Hydration of aromatic terminal alkynes catalyzed by sulfonated condensed polynuclear aromatic (S-COPNA) resin in water

Hydration of aromatic terminal alkynes in the presence of a catalytic amount of sulfonated condensed polynuclear aromatic (S-COPNA) resin in water gave the corresponding methyl ketones in good yields. On the other hand, aliphatic terminal alkynes did not react at all under the employed conditions. Chemoselective hydration of aromatic terminal alkyne in the presence of aliphatic terminal alkyne catalyzed by S-COPNA resin was carried out.     

Synthesis of Unsymmetrical 1,3‐Diynes via Pd/Cu‐Catalyzed Cross‐Coupling of Terminal Alkynes at Room Temperature

A facile and practical synthetic route of unsymmetrical 1,3‐diynes via the PdCl/CuI catalyzed oxidative coupling of two different terminal alkynes has been developed by using 3‐(diphenylphosphino)propanoic acid as a ligand in the presence of oxygen. This system is suitable for not only aromatic alkynes but also heteroaromatic and aliphatic alkynes which were transformed into the corresponding unsymmetrical 1,3‐diynes in moderate to good yields at room temperature. Moreover, the unsymmetrical 1,3‐diynes were also obtained on a multi‐gram scale. Mechanistic studies suggest that oxygen plays a key role in the catalytic cycles.     

Acylation of thermal acetylenes

Conclusions A new method was developed for obtaining acetylenic ketones via the reaction of terminal acetylenes with the acid chlorides of aliphatic and aromatic acids in the presence of catalytic amounts of CuI without using Pd compounds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1158–1159, May, 1981.     

New approach to phosphinoalkynes based on Pd- and Ni-catalyzed cross-coupling of terminal alkynes with chlorophosphanes

[reaction: see text] The first example of direct phosphination of terminal alkynes with chlorophosphanes catalyzed by Ni or Pd complexes is described. Both aromatic and aliphatic terminal acetylenes undergo the coupling reaction to give corresponding coupling product in high yield.     

Polymer - supported cobalt (II) catalysts for the oxidation of alkenes

Polymer-supported heterogeneous catalysts in a form of complexes of 8-hydroxy- quinoline with cobalt acetate were synthesized. Conjugated polymers - polyaniline (PANI), poly-o-toluidine (POT), poly-o-anisidine (POA) - were used as supports. Oxidation reactions of aliphatic and aromatic hydrocarbons were carried out in the presence of molecular oxygen at atmospheric pressure and epoxides or ketones were obtained as the main products with high selectivity.     

Synthesis of diynes and tetraynes from in situ desilylation/dimerization of acetylenes

[reaction: see text]. An efficient method for the in situ desilylation/oxidative dimerization of (trialkylsilyl)acetylenes is described. This protocol avoids the complications encountered with sensitive diynes by eliminating the deprotection and isolation steps. Various aromatic and alkyl diynes and tetraynes can be synthesized in a straightforward manner in good yields (82-99%) from TIPS-protected acetylenes. This method facilitates the efficient synthesis of novel tetrayne-bridged acetylenic cyclophanes 6 and 7 in a direct manner.     

Palladium-catalyzed oxidative homocoupling reaction of terminal acetylenes using trans-bidentatable 1-(2-pyridylethynyl)-2-(2-thienylethynyl)benzene

Palladium-catalyzed oxidative homocoupling of terminal acetylenes, in air, occurred in the presence of 1-(2-pyridylethynyl)-2-(2-thienylethynyl)benzene as ligand, affording the corresponding conjugated diynes.     

Ligand-Free Synthesis of 1,4-Disubstituted-1,3-diynes by Iron/Copper Cocatalyzed Homocoupling of Terminal Alkynes

A simple and efficient protocol for Fe/Cu cocatalyzed oxidative homocoupling reaction of terminal alkynes to symmetrical 1,4‐disubstituted‐1,3‐diynes was presented. The results showed that both CuBr and FeCl₃ played crucial roles in the reaction. It is noteworthy that this protocol employs mild, efficient, aerobic and ligand free conditions. The alkynes, including aromatic, heteroaromatic and aliphatic alkynes, were transformed into the corresponding 1,3‐diynes in good to excellent yields.     

Polymerization of aliphatic disubstituted acetylenes by MoOCl4–n‐Bu4Sn–EtOH catalyst: Formation of polymers with narrow MWDs and confirmation of the living character

The polymerization of aliphatic disubstituted acetylenes was examined with MoOCl₄–n‐Bu₄Sn–EtOH (1/1/2) ternary catalyst in anisole at 0 °C. Various linear aliphatic disubstituted acetylenes such as 2‐nonyne provided polymers with narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight = 1.05–1.20). The living character of the polymerization was proven by both the time profile of the polymerization and the multistage polymerization of 2‐nonyne. The initiation efficiency was about 3%, which is rather low. Although 5‐dodecyne, which has a triple bond in a more inner part, polymerized more slowly than 2‐nonyne, their living characters were hardly different. Diblock copolymers were synthesized by the sequential living polymerization of internal linear alkynes. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2697–2701, 2000     

Investigation of polyimides containing naphthalene units. IV. Mechanism of naphthalisoimides formation and their isomerization to naphthalimides

During high-temperature condensation of six-membered naphthalene anhydrides with aromatic primary amines, at first, naphthalisoimides were formed, having cis or trans structures in dependence on absence or presence of acidic catalysts. Only the trans naphthalisoimides isomerized to the naphthalimides in the presence of basic catalysts during heating or UV irradiation. The mechanism of naphthalisoimides formation and their rearrangement to naphthalimides has been proposed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3523–3529, 1999     

p-TsOH mediated solvent and metal catalyst free synthesis of nitriles from aldehydes via Schmidt reaction

A new and efficient protocol for the conversion of aldehyde into nitriles by modified Schmidt reaction. The reaction is carried out under solvent free condition using sodium azide as a source of nitrogen and catalysed by p-toluene sulphonic acid in presence of silica surface with no side product. This transformation gives good to excellent yield for numerous aromatic, aliphatic and heterocyclic nitriles using very simple reagent. This method has avoided the use of transition metal catalyst, toxic cyanide, hazardous solvent and offers a greener, simple and environment friendly procedure.     

Radical ring-opening polyaddition of a bifunctional vinylcyclopropane bearing a spiroacetal moiety with dithiols

Radical polyadditions of vinylcyclopropane having spiroacetal moiety, 1,10-divinyl-4,8,12,15-tetraoxatrispiro[2.2.2.2.2.2] pentadecane ( 1 ), and various dithiols were examined. 1 was prepared by the reaction of 1,1-dichloro-2-vinylcyclopropane and pentaerythritol, and radical polyadditions of 1 and dithiols were carried out at 60 and 120°C for 20 h in the presence of an appropriate initiator (3 mol % vs. 1 ) in degassed sealed ampoules or at 20°C under photo irradiation by using a 400 W high-pressure mercury lamp. Poly( 1 ), pale yellow transparent viscous polymers was isolated by reprecipitation with ether containing a small amount of triethylamine to avoid hydrolysis of the polymer. The obtained polymers were soluble in chlorobenzene, DMF, and chloroform but insoluble in ether and n-hexane. The molecular weights of the polymers obtained from aliphatic dithiols were smaller than those from aromatic ones. The structure of the polymer was determined by comparing the NMR spectra with those of the model compounds, which were obtained by radical addition of 1 and benzyl mercaptan. The reaction proceeded through radical polyaddition of dithiol to 1 via radical ring-opening polymerization of the cyclopropane ring. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2487–2492, 1997     

Polymerization of Phenylacetylene by Molybdenum (V) Chloride Activated by Acetylene Compounds

Abstract

The activating effect of acetylenic compounds for the polymerization of phenylacetylene by molybdenum (V) chloride. The alkyl and aromatic terminal acetylenes were found to activate the MoCl5 for the polymerization of phenylacetylene. The terminal acetylenes having acidic hydrogen (functional group: carboxylic acid, hydroxy) also activate the MoCl5 catalysts. On the other hand, the polymerization of phenylacetylene using MoCl5-acetylenic amines did not proceed.     

The preparation of hyperbranched aromatic and aliphatic polyether epoxies by chloride‐catalyzed proton transfer polymerization from ABn and A2 + B3 monomers

Hyperbranched polymers consisting of aromatic or aliphatic polyether cores and epoxide chain‐end peripheries were prepared by proton transfer polymerization. AB₂ diepoxyphenol monomer 1 proved to be well suited for the preparation of hyperbranched aromatic polymer 2 by this proton transfer polymerization. The use of chloride‐ion catalysis, rather than conventional base catalysis, for the preparation of polymers from diepoxyphenol 1 offered a unique method to control the ultimate molecular weight of the polymer product through variations of the initial concentration of monomer 1 in tetrahydrofuran. An alternative route to hyperbranched polyether epoxies made use of commercially available or easily prepared aliphatic monomers of the types AB₂, AB₃, and A₂ + B₃. Although these aliphatic polymerizations can be initiated with a base, chloride‐ion catalysis proved most effective for controlling the polymerization. The hyperbranched epoxies were characterized by NMR spectroscopy, gel permeation chromatography, and multi‐angle laser light scattering. Chemical modification of the polymers after polymerization was carried out via nucleophilic addition on the epoxide groups or derivatization of the hydroxy substituents within the hyperbranched polymer structure. Spectroscopic measurements suggested that some such ring‐opened materials may adopt reverse unimolecular micellar structures in appropriate solution environments. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4850–4869, 2000     

Synthesis and characterization of novel polyaryloxydiphenylsilane derived from 2,2′- dimethyl-biphenyl-4,4′-diol

A novel polyaryloxydiphenylsilane was synthesized successfully by solution polycondensation of 2,2′-dimethyl-biphenyl-4,4′-diol with diphenyldichlorosilane and the catalyst triethylamine in toluene at 80 °C. Polymers with a relatively high inherent viscosity and yield were obtained when the reactions were carried out in aromatic and lipophilic solvents. The novel polyaryloxydiphenylsilane was soluble in chlorinated aliphatic hydrocarbons such as methylene chloride and chloroform as well as in polar solvents such as dimethyl sulfoxide, N,N-dimethylformamide, and N,N-dimethylacetamide and also in some common organic solvents such as benzene and toluene. However, it was insoluble in both aliphatic hydrocarbons as well as in alcoholic solvents. The polyaryloxydiphenylsilane began losing weight around 400 °C under a nitrogen atmosphere, and the 10% weight-loss temperature was 473 °C. The glass-transition temperature of the polyaryloxydiphenylsilane was 102 °C. The glass transition could be lowered by the copolymerization technique with 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane as an aromatic diol comonomer. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4591–4595, 1999