聚对苯撑乙烯类电致发光材料研究进展

从聚合物结构修饰、复合/共混以及合成工艺等方面概述了近十多年来聚对苯撑乙烯衍生物的研究进展和发展趋势.为获得高效、稳定、可溶的PPVs型有机光电材料,可通过引入吸电子基团(如氟原子、氰基、含氮杂环等)等对其结构进行修饰来改善其平衡电荷传输的能力进而提高其发光效率;同时,通过引入长链取代基和液晶单元结构来兼顾聚合物的溶解性和稳定性,以提高材料的可加工性和器件的稳定性.通过复合/共混可以控制聚合物膜的聚集态来提高发光效率.     

Synthesis of isomeric 1,3- and 1,4-bis[3(4)-nitrofuroxan-4(3)-yl]nitrobenzenes by nitration of the corresponding isomeric 1,3- and 1,4-bis[3(4)-nitrofuroxan-4(3)-yl]benzenes

Isomeric 1,3- and 1,4-bis[3(4)-nitrofuroxan-4(3)-yl]nitro(dinitro)benzenes were synthe-sized in high yields by nitration of the corresponding 1,3- and 1,4-bis[3(4)-nitrofuroxan-4(3)-yl]benzenes with a mixture of 100% nitric acid and concentrated sulfuric acid. The influence of 3- and 4-nitrofuroxanyl fragments on the regioselectivity of the nitration was revealed. The structure of 1,3-bis(4-nitrofuroxan-3-yl)-4-nitrobenzene was confirmed by X-ray diffraction analysis. 1,3- and 1,4-Bis(3-nitrofuroxan-4-yl)nitrobenzenes underwent thermal isomerization to more thermodynamically favorable 1,3- and 1,4-bis(4-nitrofuroxan-3-yl)nitrobenzenes.     

Ru(II)-catalyzed [2 + 2 + 2] cycloaddition of 1,2-bis(propiolyl)benzenes with monoalkynes leading to substituted anthraquinones

[2 + 2 + 2] cycloadditions of 1,2-bis(propiolyl)benzenes with monoalkynes were effectively catalysed by Cp*RuCl(cod) under mild conditions to give substituted anthraquinones in moderate to high yields.     

Catalytic [2+2+2] and thermal [4+2] cycloaddition of 1,2-bis(arylpropiolyl)benzenes

We have determined that a cationic rhodium(I)/Segphos complex catalyzes an enantio- and diastereoselective intermolecular [2+2+2] cycloaddition of 1,2-bis(arylpropiolyl)benzenes with various monoalkynes at room temperature to give axially chiral 1,4-teraryls possessing an anthraquinone structure in good yields with good enantio- and diastereoselectivities. We have also determined that a thermal intramolecular [4+2] cycloaddition of 1,2-bis(arylpropiolyl)benzenes proceeds at 60 degrees C to give aryl-substituted naphthacenediones in moderate to good yields.     

Synthesis of bromo-, boryl-, and stannyl-functionalized 1,2-bis(trimethylsilyl)benzenes via Diels-Alder or C-H activation reactions

1,2-Bis(trimethylsilyl)benzenes are key starting materials for the synthesis of benzyne precursors, Lewis acid catalysts, and certain luminophores. We have developed efficient, high-yield routes to functionalized 4-R-1,2-bis(trimethylsilyl)benzenes, starting from either 1,2-bis(trimethylsilyl)acetylene/5-bromopyran-2-one (2) or 1,2-bis(trimethylsilyl)benzene (1)/bis(pinacolato)diborane. In the first reaction, 5 (R = Br) is obtained through a cobalt-catalyzed Diels-Alder cycloaddition. The second reaction proceeds via iridium-mediated C-H activation and provides 8 (R = Bpin). Besides its use as a Suzuki reagent, compound 8 can be converted into 5 with CuBr(2) in i-PrOH/MeOH/H(2)O. Lithium-bromine exchange on 5, followed by the addition of Me(3)SnCl, gives 10 (R = SnMe(3)), which we have applied for Stille coupling reactions. A Pd-catalyzed C-C coupling reaction between 5 and 8 leads to the corresponding tetrasilylbiphenyl derivative. The bromo derivative 5 cleanly undergoes Suzuki reactions with electron-rich as well as electron-poor phenylboronic acids.     

Highly (Z)-selective hydrosilylation of terminal alkynes catalyzed by a diphosphinidenecyclobutene-coordinated ruthenium complex: application to the synthesis of (Z,Z)-bis(2-bromoethenyl)arenes

[reaction: see text] Complex 1 bearing a diphosphinidenecyclobutene ligand (DPCB-OMe) catalyzes highly stereoselective hydrosilylation of diethynylarenes with HSiMe2Ph to afford (Z,Z)-bis(2-silylethenyl)arenes. Treatment of the hydrosilylation products with N-bromosuccinimide causes bromodesilylation in a stereospecific manner, giving (Z,Z)-bis(2-bromoethenyl)arenes in high geometrical purity (>98%).     

Photoinduced Gilch Polymerization: A Basically New Access to Poly(p‐phenylene vinylenes) (PPVs) of Exciting Constitutional Homogeneity

A novel procedure has been developed for the Gilch reaction leading to poly(p‐phenylene vinylenes) (PPVs). In the first step, selective activation of the starting material is achieved at low temperature. Subsequently, controlled chain growth is induced by lighting the α‐halo‐p‐quinodimethane monomer. In contrast to the thermal Gilch polymerization, the photoinduced process allows adjusting crucial parameters such as intensity and energy of light. The progress of PPV formation can be followed visually or by in situ UV–vis spectroscopy. If the polymers are formed under appropriate conditions, they show very high molar masses, polydispersities in the common range, and higher constitutional homogeneity than thermally grown PPVs.

     

Amino-Substituted para-Phenylenevinylenes (PPVs) as Platforms for Fluorescent Sensing Materials

Summary: Soluble para-phenylenevinylenes (PPVs) with amino side groups and different spacers have been synthesized. Photophysical properties showed that these compounds emitted light in blue region when dissolved in methanol. They have been designed in order to be platforms for attaching different functional groups to the amino units. Molecule 5 was a model compound which showed a quantum efficiency of 52% in methanol. Different spacers were added to the model compound to yield molecules 6 and 7 . The preliminary experiment showed that molecule 5 can interact with various metal ions in solution phase. The interaction was observed by the changes of fluorescent emission intensity of the molecule. This molecule will be further functionalized to be more specific in binding certain metal ions.     

Methylenverbindungen von Nichtmetallen. VI. Amide der Methan-bis(phosphonigsäure), -bis(phosphonsäure) und -bis(thiophosphonsäure)

Methylene Compounds of Non-Metals. VI. Amides of Methane-bis(phosphonous Acid), -bis(phosphonic Acid) and -bis(thiophosphonic Acid) Symmetrical- and asymmetrical-substituted amides of methane-bis(phosphonous acid), -bis(phosphonic acid) and -bis(thiophosphonic acid) have been obtained by stepwise aminolysis of the chlorides Cl₂(Z)PCH₂P(Z)Cl₂ ( 1 : Z = electron pair; 7 : Z = S; 13 : Z = O) and the fluoride F₂(S)PCH₂P(S)F₂ 19 with dimethylaminotrimethylsilane. Oxidation reactions of trivalent phosphonous amides with sulfur and dimethylsulfoxide have also been investigated.     

Synthesis of naphtho[b]cyclobutenes from 1,2-bis(3-propynol)benzenes

We have demonstrated that the reaction of benzene-bridged bis(propargyl alcohol)s with chlorodialkylphosphines exclusively afforded 3,8-bis(dialkylphosphinyl)naphtho[b]cyclobutenes via the [2+2] cycloaddition of 1,2-bis(α-phosphinylallenyl)benzenes. Dephosphinylation of the product has also been achieved.     

Synthesis and Electrochemical Properties of 2,5-Disubstituted 1,4-Bis(4,5-diphenyl-1H-imidazol-2-yl)benzene Derivatives

Russian Journal of Organic Chemistry - 2,5-Disubstituted 1,4-bis(4,5-diphenyl-1H-imidazol-2-yl)benzenes have been synthesized, and their electrochemical properties have been studied by cyclic...     

Catalytic hydrogenation of 2,5-bis(p-nitrophenyl)pyrimidine

We have studied the catalytic hydrogenation of 2,5-bis(p-nitrophenyl)pyrimidine over palladium on carbon under different conditions. We have established that hydrogenation in acetic acid at atmospheric hydrogen pressure leads to formation of 2,5-bis(p-aminophenyl)-1,4,5,6-tetrahydropyrimidine. Upon hydrogenation under pressure in DMF, along with 2,5-bis(p-aminophenyl)pyrimidiine, three isomeric (aminophenyl)pyrimidyl-substituted benzenes are formed as by-products. The mixture of these arylazo derivatives can be smoothly reduced by hydrogen under pressure in the presence of Raney nickel to bis(aminophenyl)pyrimidine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1534–1539, November, 1993.We would like to acknowledge V.I. Mamatyuk and M. M. Shakirov for helping record and interpret the PMR spectra.     

Highly active Pd(II) catalysts with trans-bidentate pyridine ligands for the Heck reaction

[reaction: see text] The air-, water-, and heat-stable palladium(II) complexes 2a and 2b are prepared by the reaction of palladium(II) salts with the new trans-bidentate nitrogen ligands, 1,2-bis(2-pyridylethynyl)benzenes. The structure of complex 2a has been confirmed by X-ray structure analysis. The complexes efficiently catalyze the Heck olefination of aryl iodides and provide a good yield under phosphine-free conditions. The reaction is very sensitive to the nature of the chelating ligand.     

Perfluoroalkylation of benzene derivatives. An improved synthesis of 1,3-bis(2-hydroxyhexafluoro-2-propyl)-5-(perfluoro-n-alkyl)benzenes

A three-step high yield synthesis of various 1,3-bis(2-hydroxyhexafluoro- 2-propyl)-5-(perfluoro-n-alkyl)benzenes is described. Significant improvements in the iodination and perfluoro-alkylation of a perfluoroalkylbenzene diol have been achieved. Copper coupling of straight-chain perfluoroalkyl iodides with the iodobenzene derivative in DMSO gave the desired compounds as DMSO complexes in 78–91 percent yield.     

Highly stereoselective synthesis of (Z)-1,2-dihaloalkenes by a Pd-catalyzed hydrohalogenation of alkynyl halides

An unprecedented Pd-catalyzed hydrohalogenation of alkynyl halides for the regio- and stereoselective synthesis of (Z)-1,2-dihaloalkenes has been realized using [(allyl)PdCl](2) as the catalyst and cis,cis-1,5-cyclooctadiene as the ligand. The advantages of this protocol are well illustrated by the assembly of trisubstituted (Z)-enynes and multifunctional benzenes via iterative cross-coupling reactions or tandem Diels-Alder-aromatization reactions, respectively.     

Fluorobenzo-1,4-thiazine oxides from bis-(vinylsulfinyl)-and bis(vinylsulfonyl)-fluorobenzenes and 2-aminoethanol

It has been established that 1, 2, 4, 5-tetrafluoro-3, 6-bis (vinylsulfinyl)- and 1, 2, 4, 5-tetrafluoro-3, 6bis(vinylsulfonyl)benzenes react with 2-aminoethanol by nucleophilic addition at the activated double bond with replacement of fluorine atoms on the benzene ring by the amino group of 2-aminoethanol to give 4, 9-bis(2 hydroxyethyl)-5,10-difluoro-1, 2, 3, 4, 6, 7, 8, 9-octahydrobenzo[1, 2-b; 5, 4-b]di-1, 4-thiazine 1,6-dioxide and 1, 1, 6, 6-tetraoxide respectively.Irkutsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences (SO RAN), Irkutsk 664033. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1195–1198, September, 1996. Original article submitted June 5, 1996.Deceased     

Synthesis and Biological Evaluation of C(13)/C(13′)-Bis(desmethyl)disorazole Z**

We describe the total synthesis of the macrodiolide C(13)/C(13′)-bis(desmethyl)disorazole Z through double inter-/intramolecular Stille cross-coupling of a monomeric vinyl stannane/vinyl iodide precursor to form the macrocycle. The key step in the synthesis of this precursor was a stereoselective aldol reaction of a formal Evans acetate aldol product with crotonaldehyde. As demonstrated by X-ray crystallography, the binding mode of C(13)/C(13′)-bis(desmethyl)disorazole Z to tubulin is virtually identical with that of the natural product disorazole Z. Likewise, C(13)/C(13′)-bis(desmethyl)disorazole Z inhibits tubulin assembly with at least the same potency as disorazole Z and it appears to be a more potent cell growth inhibitor.     

Sodium dithionite initiated addition of CF2Br2, CF3I and (CF3)2CFI to allylaromatics: Synthesis and the reactivity of 4-aryl-1,1-difluorodienes and 4-aryl-1,1-bis(trifluoromethyl)dienes

Sodium dithionite initiated addition of CF₂Br₂, CF₃I and (CF₃)₂CFI to the terminal double bond of allylbenzenes and of (CF₃)₂CFI to allylpyridines in a MeCN/H₂O system were investigated. The reactions of CF₂Br₂ with allylbenzenes gave comparable amounts of adducts, 1-(2,4-dibromo-4,4-difluorobutyl)benzenes, debrominated products,1-(4-bromo-4,4-difluorobutyl)benzenes, and dimeric compounds in total yields 40-66%. Treatment of the adducts with DBU resulted in double dehydrohalogenation affording 4-aryl-1,1-difluorobutadienes which undergo Diels-Alder condensation with nitrogen dienophiles to give N-heterocycles with difluoromethylene group in the ring. The reactions of CF₃I and (CF₃)₂CFI with allylbenzenes gave the respective adducts, (4,4,4-trifluoro-2-iodobutyl)benzenes and 1-(4,5,5,5-tetrafluoro-4-(trifluoromethyl)-2-iodopentyl)benzenes as the main products. Dehydrohalogenation of these adducts resulted, respectively, in (4,4,4-trifluoro-but-1-enyl)benzenes and 4-aryl-1,1-bis(trifluoromethyl)butadienes in high yields. (CF₃)₂CFI reacted rapidly with allylpyridines to give mixtures from which, after treatment with DBU, 4-pyridyl-1,1-bis(trifluoromethyl)butadienes were isolated in a ca. 60% yield.     

A simple synthesis of di(uracilyl)aryl methanes and 1,ω-bis[di(uracilyl)methyl]benzenes

Di(uracilyl)aryl methanes and their homologues, 1,ω-bis[di(uracilyl)methyl]benzenes, have been synthesized in good yields through the HBr-acetic acid catalyzed condensation of 1-alkyl-/1,3-dialkyluracil derivatives with readily available aryl aldehydes and dialdehydes.     

Zirconium-mediated Selective Synthesis of 1,4-Dialkyl(aryl)-hexa-substituted Benzenes from Two Silyl-substituted Alkynes and One Internal Alkyne

Based on the formation of 2,5-bis(trimethylsilyl)-zirconacyclopentadienes from two silylalkynes with Cp₂ZrBu₂ and the Cu-mediated formation of 1,4-disilylbenzene via the cycloaddition of zirconacyclopentadienes to disubstituted alkynes, a selective synthesis of 1,4-dialkyl(aryl)-hexa-substituted benzenes was achieved followed by iodination and coupling reaction. The coupling reactions were carried out with either organolithium reagent or organozinc reagent(Negishi coupling), depending on the electrophilic species.