- Highly selective ensembles for D-fructose based on fluorescent method in aqueous solution
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Three highly sensitive and selective switches for monosaccharides were composed by anionic polyelectrolyte PPPSO3Na and cationic viologen quencheres BBVs. The sensing processes of three ensembles (PPPSO 3Na/o-BBV, PPPSO3Na/m-BBV and PPPSO3Na/p-BBV) to common seven monosaccharides have been determined by fluorescence spectra at pH 7.4 buffer solution. The results show that the three sensing ensembles all embody higher selectivity and sensitivity for d-fructose with reversible "on-off-on" fluorescence response. The research results can provide a new mode for developing highly selective probes.
- Wang, Zhijun,Lei, Haiying,Zhou, Chengyong,Wang, Guofeng,Feng, Liheng
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- A versatile strategy to directly synthesize 4,8-functionalized benzo[1,2-b:4,5-b′]difurans for organic electronics
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A direct synthesis of 4,8-functionalized benzo[1,2-b:4,5-b′]difurans (BDFs) is developed. By fine-tuning the energy levels with different 4,8-functionalities or incorporating with electron-accepting units, BDFs show great potential as organic electronic materials, as demonstrated by 4.61% power conversion efficiency for polymer solar cells.
- Bian, Linyi,Hai, Jiefeng,Zhu, Enwei,Yu, Jiangsheng,Liu, Yun,Zhou, Jie,Ge, Guidong,Tang, Weihua
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- A highly sensitive water-soluble system to sense glucose in aqueous solution
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A glucose sensing switch is formed by water soluble conjugated polymer (PP-S-BINOL) and boronic acid-functionalized benzyl viologen (o-BBV). The two-component system shows a high sensitivity for glucose sensing with a 17-fold increase in the fluorescence intensity in the presence of 100 mM glucose.
- Feng, Liheng,Liang, Fei,Wang, Yue,Xu, Ming,Wang, Xiaoju
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- Aldehyde-functionalized, water-soluble poly(para-phenylene): Synthesis and streptavidin assay using FRET
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We have attempted to synthesize water-soluble poly(para-phenylene) derivative, poly{[2,5-bis(3- sulfonatobutoxy)-1,4-phenylene sodium salt]-a/f-(1,4-phenylene)} (PPP-SO3). Aldehyde groups, versatile functional intermediate groups for immobilization of biomolecules, were introduced at both ends of PPP-SO3 chain to produce PPP-SO 3-CHO. PPP-SO3-CHO showed good solubility in aqueous solution and blue emission color, which was expected as an energy donor in FRET mechanism. Biotin was attached to the polymer end groups via imine linkage to use as a ligand for streptavidin immobilization. The biotin coupled with polymer chain enables the polymer to bind with FITC-streptavidin leading to energy transfer from the blue-emitting polymer to green-emitting FITC via FRET. Copyright
- Kwak, Chan Kyu,Kim, Dong Myung,Lee, Chang-Soo,Lee, Minjung,Lee, TaekSeung
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- Chirality Induction through Nano-Phase Separation: Alternating Network Gyroid Phase by Thermotropic Self-Assembly of X-Shaped Bolapolyphiles
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The single gyroid phase as well as the alternating double network gyroid, composed of two alternating single gyroid networks, hold a significant place in ordered nanoscale morphologies for their potential applications as photonic crystals, metamaterials and templates for porous ceramics and metals. Here, we report the first alternating network cubic liquid crystals. They form through self-assembly of X-shaped polyphiles, where glycerol-capped terphenyl rods lie on the gyroid surface while semiperfluorinated and aliphatic side-chains fill their respective separate channel networks. This new self-assembly mode can be considered as a two-color symmetry-broken double gyroid morphology, providing a tailored way to fabricate novel chiral structures with sub-10 nm periodicities using achiral compounds.
- Chen, Changlong,Ebert, Helgard,Kieffer, Robert,Liu, Feng,Prehm, Marko,Tschierske, Carsten,Ungar, Goran,Zeng, Xiangbing,Zhang, Rui-bin
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- Effective shielding of triplet energy transfer to conjugated polymer by its dense side chains from phosphor dopant for highly efficient electrophosphorescence
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To examine the quenching of a triplet exciton by low triplet energy (E T) polymer hosts with different chain configurations for high E T phosphor guests, the quenching rate constant measurements were carried out and analyzed by the standard Stern-Volmer equation. We found that an effective shielding of triplet energy transfer from a high ET phosphor guest to a low ET polymer host is possible upon introducing dense side chains to the polymer to block direct contact from the guest such that the possibility of Dexter energy transfer between them is reduced to a minimum. Together with energy level matching to allow charge trapping on the guest, high device efficiency can be achieved. The extent of shielding for the systems of phenylene-based conjugated structures from iridium complexes follows the sequence di-substituted (octoxyl chain) in the para position (dC 8OPPP) is greater than monosubstituted (mC8OPPP) and the PPPs with longer side chains are much higher than a phenylene tetramer (P4) with two short methyl groups. Further, capping the dialkoxyl-susbstituents with a carbazole (Cz) moiety (CzPPP) provides enhanced extent of shielding. Excellent device efficiency of 30 cd/A (8.25%) for a green electrophosphorescent device can be achieved with CzPPP as a host, which is higher than that of dC 8OPPP as host (15 cd/A). The efficiency is higher than those of high ET conjugated polymers, poly(3,6-carbazole) derivatives, as hosts (23 cd/A). This observation suggests a new route for molecular design of electroluminescent polymers as a host for a phosphorescent dopant.
- Huang, Szu-Po,Jen, Tzu-Hao,Chen, Yen-Chun,Hsiao, An-En,Yin, Shu-Hui,Chen, Hsiang-Yun,Chen, Show-An
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- Diels-Alder trapping of in situ generated dienes from 3,4-dihydro-2H-pyran with p-quinone catalysed by p-toluenesulfonic acid
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This comprehensive study portrays that p-toluenesulfonic acid is a more efficient catalyst for the reaction between p-quinones and 3,4-dihydro-2H-pyran, than the Lewis acids. The products were accomplished by the Diels-Alder cycloaddition reaction and their mechanistic pathways have been formulated. The impact of C2 and C2,5 substituents of the p-quinones on the cycloaddition reaction has been explored. Remarkably, it is the first report to explore this kind of in situ generated diene for the Diels-Alder cycloaddition reaction.
- Mohan Raj, Radhakrishnan,Balasubramanian, Kalpattu K.,Easwaramoorthy, Deivanayagam
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- Blue-light-emitting cationic water-soluble polyfluorene derivatives with tunable quaternization degree
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The design, synthesis and characterization of novel blue emission cationic water-soluble conjugated polymers based on the polyfluorene (PF) derivatives with amino-terminal groups are described. Water solubility was realized through quaternization of the amino group, which permits a control of the cationic degree, which in turn determines the solubility of the polymers in organic solvents and water. Better solubility in polar solvents was accompanied by a spectral blue shift for polymers with a higher quaternization degree. In the presence of a trace amount of some weak organic acids, the neutral polymer also showed a high solubility in water. Instead of forming a quaternized salt, the 1H NMR spectra indicated that only electrostatic interaction existed between the acid and the amino-terminal groups, which increased the affinity of the polymers with those polar solvents. In addition to the special solubility, good thermal stability as well as the intense fluorescence both in solutions and as films endows this series of materials with the status of most attractive candidates as the transporting/emitting layer in multilayer device fabrication.
- Liu, Bin,Yu, Wang-Lin,Lai, Yee-Hing,Huang, Wei
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- Reversible "off-on" fluorescent probe for anions based on a facile two-component ensemble
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A specific fluorescent switch for anions was successfully constructed. The novel sensing switch is a two-component ensemble, which was combined using a water-soluble conjugated polyelectrolyte and a boronic acid functionalized pyridine salt. In the ensemble, the polyelectrolyte is used as a fluorescent signal unit, and the pyridine boronic acid acts as receptor and quencher. The two-component ensemble shows a fluorescence reversible "off-on" response toward cyanide and phosphate anions based on different binding ways. Furthermore, the facile design and construction of this ensemble presents a novel opportunity for obtaining an efficient and practical probe.
- Wang, Xiaoju,Feng, Liheng,Zhang, Liwei
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- Simultaneous and dual emissive imaging by micro-contact printing on the surface of electrostatically assembled water-soluble poly(p-phenylene) using FRET
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Poly{[2,5-bis(3-sulfonatobutoxy)-1,4-phenylene sodium salt]-alt-(1,4- phenylene)}, which is an anionically charged, water-soluble poly(para-phenylene) derivative with aldehyde groups at both chain ends, is prepared via the Suzuki coupling reaction in order to develop a FRET energy donor, while simultaneously dual-fluorescence-patterning the protein. Regardless of the end-capping, the synthesized polymer exhibits a good solubility in water with an absorption maximum at 338 nm and a photoluminescence maximum at 417 nm, similar to those of the the end-capped polymer. The emission spectrum of the polymer overlaps the absorption spectrum of fluorescein, and therefore, the polymer can be used as an energy donor with fluorescein as the energy acceptor in the FRET mechanism. This polymer design not only takes advantage of the introduction of biotin at both chain ends (through a reaction with the aldehyde end groups) to realize the facile interaction with streptavidin, but also brings into play the electrostatic features of the anionic sulfonate groups to fabricate an electrostatic self-assembly with polycation for the pattern substrate. The micropattern of fluorescein-labeled streptavidin is fabricated on the polymer-coated substrate through micro-contact printing using a polydimethylsiloxane mold. As a result, the polymer substrate exhibits a dual fluorescence micropattern, which results from the blue emission color from the energy donor and the FRET-amplified green emission from the energy acceptor. The high-resolution patterning is carried out for the application of multiplexing by simultaneously imaging the patterned green-emitting fluorescein by FRET and the surrounding blue-emitting polymer according to an optical detection scheme. A simultaneous and dual protein patterning process is developed on the surface of a electrostatically self-assembled blue-emitting poly(p-phenylene) derivative by using a micro-contact-printing technique and FRET. After passivation with bovine serum albumin to prevent nonspecific interactions between ligands and proteins, FRET-amplified fluorescein isothiocyanate labeled streptavidin is patterned with green emission on the blue-emitting background, for a convenient recognition of the pattern by notable color difference. Copyright
- Kwak, Chan Kyu,Kim, Dai Geun,Kim, Tae Hyeon,Lee, Chang-Soo,Lee, Minjung,Lee, Taek Seung
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- Synthesis of PPP-b-PS block copolymers using a combination of Suzuki-polycondensation and nitroxide-mediated radical polymerization
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The synthesis of π-conjugated Nitroxide-Mediated Radical Polymerization (NMRP)-macroinitiators by Suzuki-polycondensation in a one-step reaction has been investigated using conventional and microwave-heating in presence of a suitable terminating agent. Alkoxyamine-functionalized poly(para-phenylene)s were initially synthesized by Suzuki-polycondensation and then its block copolymer with styrene by NMRP. Molecular weight and molecular weight distribution of the polymers have been determined in SEC-measurements, while end-group determination was performed with MALDI-ToF-MS. Thin-layer-morphologies of the block copolymers were investigated using tapping-mode AFM.
- Britze, Antje,Jacob, Josemon,Choudhary, Veena,Moellmann, Vera,Grundmeier, Guido,Luftmann, Heinrich,Kuckling, Dirk
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- A high efficiency pure organic room temperature phosphorescence polymer PPV derivative for OLED
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For the purpose of improving device efficiency and reducing cost, it is necessary to develop pure organic molecules with room temperature phosphorescence (RTP). A high efficiency pure organic RTP polymer, poly-p-phenylene vinylene (PPV) derivative (Br-PPV-CHO), was designed and synthesized, which possesses a blue emission at 496 nm, an emission lifetime of 14.1 μs, and a photoluminescence quantum yield of 12.2%, and the HOMO and LUMO of ?5.35 eV and ?2.75 eV, respectively, showing a great potential application in the emitting layer of OLED. A device fabricated with the PPV derivative as the emitting material layer shows a max luminance of 194 cd/m2 when the Br-PPV-CHO content was 0.5 wt %, demonstrating the best RTP performance. The good properties of Br-PPV-CHO come from the substituent groups of bromine and aromatic aldehyde, and the molecular structure design strategy in the PPV derivative supplies a useful guidance for the design and syntheses of organic RTP materials.
- He, Ying,Cheng, Nianhe,Xu, Xin,Fu, Jiawei,Wang, Jun-an
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p. 247 - 251
(2018/11/30)
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- Synthesis of phenylethynylbenzenes
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A method of: reacting a dihydroxybenzene with bromine to form a bromodihydroxybenzene; reacting the bromodihydroxybenzene with trifluoromethanesulfonyl chloride or trifluoromethanesulfonic anhydride to form a bromotrifluoromethanesulfonatobenzene; and reacting the bromotrifluoromethanesulfonatobenzene with phenylacetylene to form a phenylethynylbenzene.
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(2018/06/08)
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- Aromatic diboron ester convenient synthesis method suitable for large-scale production
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The invention discloses an aromatic diboron ester convenient synthesis method suitable for large-scale production. A bibromo substrate serves as the raw material, and a metal catalyst and a reaction reagent are added under participation of alkali and bis(pinacolato)diboron for a coupling reaction, wherein reaction temperature is 70-100 DEG C, and the molar ratio of bis(pinacolato)diboron to the bibromo substrate is 1:10-10:1; after the reaction ends, diatomite is used for filtering, an organic solvent is removed, then re-crystallization and extraction are conducted, and a finished aromatic diboron ester product is obtained. The synthesis method is simple, production cost is low, and by-products, such as waste silica gel and excessive waste solvents, which are not environmentally friendly are not generated. The product is purified through the re-crystallization method, the product only needs to be crystallized and stay overnight at low temperature, a large number of solvents do not need to be consumed, workloads are reduced, purification efficiency of the product is also improved, large-scale industrial production is facilitated, and the reaction yield can reach as high as 93.6%.
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Paragraph 0012; 0019
(2017/07/01)
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- Detection of Picric Acid by Terpy-Based Metallo-Supramolecular Fluorescent Coordination Polymers in Aqueous Media
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The synthesis of two linear terpy-based metallo-supramolecular fluorescent coordination polymers through 1∶1 complexation of Zn2+ and Cd2+ ions with ditopic terpyridine ligand was reported. The dispersibility of P1 and P2 was significantly improved in organic solvent and water through the introduction of hydrophilic oligo-ethyoxy side chain. Two polymers displayed yellow light emission both in solution and the solid state due to the intra-ligand charge transfer (ILCT) between the d10 metal ions and the conjugated spacer unit. These coordination polymers were explored as fluorescent chemosensors for detecting picric acid in aqueous media, displaying high sensitivity and good selectivity. In addition, test strips were prepared from these polymers and exhibited the practical potential of detecting the NACs pollutants in the outdoor water for public safety and security.
- Ding, Zhongyu,Li, Hongqing,Gao, Wanqing,Zhang, Yiquan,Liu, Chunhua,Zhu, Yuanyuan
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p. 447 - 456
(2017/04/27)
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- Stepwise, multicomponent assembly of a molecular trapezoid possessing three different metals
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A novel terpyridine-based, trapezoidal architecture was synthesized by a coordination-driven multicomponent assembly and features three different tpy-M2+-tpy bonds (M2+ = Ru2+, Fe2+, and Zn2+) in the macrocyclic ring. This trimetallic macrocycle introduces the construction of polymetallosupramolecular assemblies possessing multiple, differing metal centers in an ordered, predetermined pattern. Characterization was accomplished by NMR spectroscopy, mass spectrometry, and UV-Vis spectroscopy.
- Yao, Yuchen,Chakraborty, Sourav,Zhu, Shiying,Endres, Kevin J.,Xie, Ting-Zheng,Hong, Wei,Manandhar, Erendra,Moorefield, Charles N.,Wesdemiotis, Chrys,Newkome, George R.
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supporting information
p. 8038 - 8041
(2017/07/22)
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- The experimental observation of the intramolecular NO2/CO interaction in solution
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The weak electrostatic interaction between nitro and carbonyl moieties has been observed by means of variable-temperature NMR spectroscopy. Its energetic contribution was evaluated to be about 3 kcal mol-1 by DFT calculations, and confirmed by the measurement of internal energy barriers to the rotation of suitable nitroaryl rings. Might without muscle: The weak electrostatic interaction between nitro and carbonyl moieties has been observed by means of variable-temperature NMR spectroscopy. Its energetic contribution was evaluated to be about 3 kcal mol-1 by DFT calculations, and confirmed by the measurement of internal energy barriers to the rotation of suitable nitroaryl rings (see picture).
- Chiarucci, Michel,Ciogli, Alessia,Mancinelli, Michele,Ranieri, Silvia,Mazzanti, Andrea
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supporting information
p. 5405 - 5409
(2014/06/09)
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- Efficient synthesis of rigid ladder polymers via palladium catalyzed annulation
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We report a new method to synthesize rigid ladder polymers using efficient palladium catalyzed annulation reactions with low catalyst loading (1 mol %). Rigid ladder polymers with benzocyclobutene backbone linkages can be synthesized from copolymerization of readily accessible aryl dibromides and norbornadiene or polymerization of AB type monomers bearing norbornene and aryl bromide or triflate moieties. High molecular weight (10-40 kDa) rigid ladder polymers can be obtained with complete monomer conversions. Diverse monomers also gave different, fixed ladder polymer conformations. The ladder polymers exhibited excellent thermal stability, high carbonization yield, and large intrinsic porosity.
- Liu, Sheng,Jin, Zexin,Teo, Yew Chin,Xia, Yan
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supporting information
p. 17434 - 17437
(2015/02/05)
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- Synthesis of water-soluble, fluorescent, conjugated polybenzodiazaborole for detection of cyanide anion in water
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A polymer sensor (P1) containing benzodiazaborole moieties for recognition of cyanide anion and sulfonate groups for water-solubility was synthesized by Suzuki cross-coupling polymerization, which enables cyanide detection in aqueous solution. The polymer showed visible fluorescence quenching upon exposure to cyanide anion concentrations as low as ～2 μM. Selective detection of cyanide anions can be accomplished via fluorescence quenching, while other anions exhibited fluorescence enhancement upon exposure, mainly due to the difference in the nucleophilicity of anions, affecting benzodiazaborole group.
- Son, Ji Hye,Jang, Geunseok,Lee, Taek Seung
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p. 3542 - 3547
(2013/07/27)
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- Side functionalization of diboronic acid precursors for covalent organic frameworks
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A series of substituted 1,4-benzenediboronic acids (BDBA) was synthesized and their thermal properties investigated. Two diboronic acids were studied as building-blocks for covalent organic framework (COF) formation, namely 2,5-dimethoxy-1,4-benzenediboronic acid and 2-nitro-1,4-benzeneboronic acid. Interestingly, substitution of the BDBA core caused a dramatic decrease of the polymerization temperature leading to the formation of a less organized structure.
- Faury, Thomas,Dumur, Frederic,Clair, Sylvain,Abel, Mathieu,Porte, Louis,Gigmes, Didier
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p. 2067 - 2075
(2013/04/23)
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- Fluorometric detection of lectin with water-soluble hyperbranched conjugated polymer using mannose mediation
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A water-soluble hyperbranched polymer containing boronic acid groups at the ends of the polymer, which are capable of binding to diol-containing mannose, was syntheized. The hyperbranched polymer was prepared by a palladium-catalyzed Suzuki cross-coupling reaction using the tribromo monomer for the hyperbranched type structure. The water-soluble hyperbranched polymer (HP) exhibited enhanced fluorescence intensity upon exposure to lectin in the presence of mannose compared to other proteins, such as lysozyme and cytochrome c, because mannose plays a key role in binding both lectin and HP resulting in selective sensing toward lectin. Copyright
- Kim, Daigeun,Jang, Geun Seok,Son, Ji Hye,Seo, Seongwon,Kim, Jongho,Kim, Tae Hyeon,Lee, Taek Seung
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scheme or table
p. 4365 - 4369
(2012/09/22)
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- Liquid crystalline PEDOT derivatives exhibiting reversible anisotropic electrochromism and linearly and circularly polarized dichroism
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The multifunctional poly(3,4-ethylenedioxythiophene) [PEDOT] derivatives that exhibit liquid crystallinity, reversible anisotropic electrochromism, and linearly and circularly polarized dichroism are developed. A series of copolymer-type liquid-crystalline PEDOT (LC PEDOT) derivatives are synthesized and evaluated in terms of optical and electrochromic properties. Two of the polymers are monosubstituted LC PEDOT derivatives with phenylcyclohexyl (PCH) or cyanobiphenyl (CB) mesogenic side chain moieties linked to the main chain via an ester bond. Four are disubstituted polymers bearing PCH or CB side chain moieties linked to the main chain via an ester or an ether bond. All of the polymers showed thermotropically nematic LC (N-LC) phases of an enantiotropic nature. Macroscopically aligned LC PEDOT derivatives were prepared by rubbing the polymer films in their N-LC phases, yielding linearly polarized fluorescence and anisotropic electrochromism. The morphologies of the polymer films reversibly changed between the neutral and oxidized states through electrochemical dedoping and doping procedures. The electrochromism between the neutral and oxidized states occurred in the parallel and perpendicular directions of the aligned polymer film, affording a novel anisotropic electrochromism. The chiral nematic LC (N*-LC) phases were also induced in the polymers by adding chiral binaphthyl derivatives as chiral inducer into the LC PEDOT derivatives. The polymer films with the induced N*-LC phase exhibited circular dichroism, implying the formation of an interchain helically π-stacked structure or intrachain helically twisted structure.
- Jeong, Yong Soo,Akagi, Kazuo
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experimental part
p. 10472 - 10481
(2012/06/04)
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- Highly selective recognition of monosaccharide based on two-component system in aqueous solution
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A highly selective switch for d-fructose was formed by water-soluble conjugated polymer PP-S-BINOL and tetraboronic acid functionalized benzyl viologen ToBV. The two-component system showed a high selectivity and sensitivity only for d-fructose in familiar d-monosaccharides. The high selectivity of the sensing system for d-fructose may be depended on stable pyranose ester form of d-fructose with ToBV. A desirable linear response of the sensing system to low concentrations of d-fructose (10.0 mM) was observed with 0.9936 linear dependent coefficient at pH 7.4.
- Feng, Liheng,Wang, Yue,Liang, Fei,Xu, Ming,Wang, Xiaoju
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experimental part
p. 3175 - 3180
(2011/05/17)
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- A glucose-selective fluorescent water-soluble hyperbranched polymer sensor with boronic acid end groups
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We have synthesized water-soluble hyperbranched poly(p-phenylene)s having boronic acid groups capable of reacting with diol-containing saccharides. The polymerization was carried out by palladium-catalyzed Suzuki cross-coupling reaction using tribromo monomer for the preparation of hyperbranched type structure. The water-soluble hyperbranched polymer HP exhibited much higher sensitivity toward glucose compared with the linear polymer LP presumably due to the difference in the number of the boronic acids which are present in the end groups of the polymers.
- Lee, Taek Seung,Kim, Dai Geun,Lee, Minjung
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experimental part
p. 54 - 61
(2011/07/09)
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- Fluorescent conjugated polymer nanoparticles by polymerization in miniemulsion
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Highly fluorescent conjugated polymer nanoparticles were prepared directly by polymerization in aqueous miniemulsion, employing Glaser coupling polymerization as a suitable step-growth reaction. A 4,4′-dinonyl-2, 2′-bipyridine-modified catalyst was found to be suited for the polymerization in the aqueous heterophase system. Nanoparticles of poly(arylene diethynylenes) (arylene = 2,5-dialkyoxy phenylenes and 9,9′-dihexyl fluorene) with molecular weights in the range of Mn 104 to 105 g mol-1 and with sizes of ≤30 nm, as observed by TEM, result. N,N′-Di(4-ethynylphenyl)-1,7-di[4-(1,1,3,3-tetramethylbutyl) phenoxy]-perylene-3,4:9,10-tetracarboxdiimide or 2,7-diethynylfluorenone was converted completely during the heterophase polymerization to afford colloidally stable nanoparticles of poly(arylene diethynylenes) with 0.1-2 mol % covalently incorporated perylene dye and 2-9 mol % of covalently incorporated fluorenone dye, respectively. Fluorescence spectroscopy of the aqueous dispersions reveals an efficient energy transfer to the dye in the nanoparticles, which enables a variation of the luminescence emission color between red (λem (max.) ca. 650 nm) and the green emission of the nanoparticles without dye.
- Baier, Moritz C.,Huber, Johannes,Mecking, Stefan
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supporting information; experimental part
p. 14267 - 14273
(2010/02/15)
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- Carbazole-containing conjugated copolymers as colorimetric/fluorimetric sensor for iodide anion
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A series of conjugated poly(p-phenylene carbazole) copolymers, poly(N-hexyl-3,6-carbazole-alt-2,5-bisdodecyloxyphenylene) [P1], poly(N-ethylhexyl-3,6-carbazole-alt-2,5-bisdodecyloxyphenylene) [P2], and poly(N-dodecyl-3,6-carbazole-alt-2,5-bisdodecyloxyphenylene) [P3] were prepared by using palladium-catalyzed Suzuki coupling reactions. All copolymers were characterized by means of FT-IR, GPC, 1H and 13C NMR, UV-vis, fluorescence spectroscopy, and X-ray powder diffraction patterns. All copolymers were soluble in common organic solvents, exhibited good thermal stability up to 390 °C, and showed UV-vis absorbance and fluorescence maxima around 328 and 394 nm, respectively. The polymers P1-P3 differed in N-alkyl substitution, i.e., n-hexyl (for P1), n-ethylhexyl (for P2), and n-dodecyl (for P3) groups. In addition, a third monomer, 2,5-substituted pyridine for poly(N-ethylhexyl-3,6-carbazole-co-2,5-didodecyloxy phenylene-co-2,5-pyridine) (P4) and dialkylated fluorene for poly(N-ethylhexyl-3,6-carbazole-co-2,5- didodecyloxy phenylene-co-9,9′-dihexylfluorene) (P5) was incorporated into the copolymer P2 to investigate the influence on their optical properties. The UV-vis and fluorescence maxima of P4 and P5 showed significant red shift in λmax by 29 and 19 nm and Δλem of 38 and 21 nm, respectively as compared to the polymers P1-P3. The quantum efficiencies of these polymers (52-78%) were relatively higher and may have good applications in the fabrication of LEDs. The UV-vis and fluorescence spectra of the polymers were significantly affected by the addition of tetrabutylammonium iodide and other metal iodides. A colorless polymer solution turns to deep yellow color on the addition of iodide salts. This change is, however, not observed in the presence of other anions such as fluoride, chloride and bromide salts. Therefore, the polymers P1-P5 may be useful in fabricating selective iodide sensors.
- Vetrichelvan, Muthalagu,Nagarajan, Rajagopal,Valiyaveettil, Suresh
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p. 8303 - 8310
(2007/10/03)
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- Intramolecular hydrogen-bond-assisted planarization of asymmetrically functionalized alternating phenylene-pyridinylene copolymers
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We report on the synthesis and characterization of a series of asymmetrically functionalized amphiphilic polymers with alternating π-donor units (e.g., substituted benzene) and π-acceptor units (e.g., pyridine) along the polymer backbone. The purpose of our present work involves incorporation of functional groups along the main chain to form intrachain hydrogen bonds, which promote planarization of the polymer backbone, and to fine-tune the optical properties. The structure-property relationship of polymers P1-P6 was investigated by means of analytical methods, such as FTIR spectroscopy, 1H and 13C NMR spectroscopy, UV/Vis spectroscopy, fluorescence spectroscopy, gel permeation chromatography, thermogravimetric analysis, cyclic voltammetry, and X-ray powder diffraction. All polymers were soluble in common organic solvents, and the optical and fluorescence spectra of the polymers showed significant changes according to the formation (P4, P5) or absence (P6) of intramolecular hydrogen bonding along the polymer backbone. Moreover, the 2,6-or 3,5-linkage of the pyridine rings in P5 and P6, respectively, reduced the conjugation along the polymer backbone and this is reflected in their optical properties. The optical properties of the polymers were influenced by the addition of acid (P1-P6), base (P4-P6), and metal ions (e.g., Cu2+, Fe3+, Ag+, Ni2+, Pd2+, Mn2+, Zn2+, Mg2+, and Pr 3+). Such polymers could be used in various applications, including sensors and stimuli-responsive displays.
- Vetrichelvan, Muthalagu,Valiyaveettil, Suresh
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p. 5889 - 5898
(2007/10/03)
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- Supramolecular ordering, thermal behavior, and photophysical, electrochemical, and electroluminescent properties of alkoxy-substituted yne-containing poly(phenylene-vinylene)s
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The synthesis and the characterization of defect-free alkoxy-substituted yne-containing poly(phenylene-vinylenes) was investigated. It was found that a degree of 7 was obtained for all the polymers enabling a reliable comparison of their properties as a function of the length and geometry of the grafted side chains. A formation of crystalline superstructures of either spherulitic-like or rodlike morphology was identified as following typical nucleation and growth process for polymer having a symmetric substitution pattern. Results show that the high absorption coefficients and high quantum yields in the solid state combined with enhanced oxidation stability made polymers as potential donor materials in the design of organic solar cells.
- Egbe, Daniel Ayuk Mbi,Carbonnier, Benjamin,Ding, Liming,Muehlbacher, David,Birckner, Eckhard,Pakula, Tadeusz,Karasz, Frank E.,Grummt, Ulrich-Walter
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p. 7451 - 7463
(2007/10/03)
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- A controlled and selective bromination of phenols by benzyltriphenylphosphonium tribromide
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Reactions of phenols with benzyltriphenylphosphonium tribromide in dichloromethane-methanol mixture (2:1) gave mono, di and tri brominated phenols at room temperature with high selectivity and good yields.
- Hajipour, Abdol Reza,Mallakpour, Shadpour E.,Imanieh, Hossein,Pourmousavi, Seied A.
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p. 272 - 275
(2007/10/03)
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- Polaron-type magnetic conjugated polymer with liquid crystallinity
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We synthesized poly(para- and meta-phenylenevinylene) derivative with liquid crystalline group. The polymer is composed of p-phenylenevinylene as a spin generating unit and m-phenylene as a ferromagnetic spin coupling unit. The polymer showed nematic LC phase. The polymer was doped by iodine to generate the polaron, after the polymer was cooled down through the LC phase. ESR measurements showed that the spin concentration increased by means of external magnetic force alignment of the polymer.
- Goto, Hiromasa,Mochizuki, Kenichi,Akagi, Kazuo
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p. 481 - 489
(2007/10/03)
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- Investigations into the bromination of substituted phenols using diethyl bromomalonate and diethyl dibromomalonate
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Substituted 4-bromophenols can be synthesised efficiently by heating the corresponding phenol in either neat diethyl bromomalonate or diethyl dibromomalonate. We discuss the regioselectivity of such reactions and comment on the scope and limitation of this procedure.
- Coumbarides,Dingjan,Eames,Weerasooriya
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p. 179 - 180
(2007/10/03)
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- Synthesis and characterization of a new conjugated polymer containing cyano substituents for light-emitting diodes
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A new luminescent conjugated polymer (CN-P3PV) containing cyano groups as electron transporting units was synthesized by a Suzuki coupling reaction. CN-P3PV was characterized by 1H NMR, FT-IR, GPC, DSC, and TGA. The synthesized polymer possessed high thermal stability (Td = 360 °C, Tg= 151 °C), high electron affinity, and good thin-film forming ability. Electrical characterization of a double-layer organic LED based on the structure of ITO/CuPc/CN-P3PV/Ca/Ag showed high electron transporting ability and good electroluminescence performance with the emission of bright orange light.
- Wu, Xia,Liu, Yunqi,Zhu, Daoben
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p. 1327 - 1331
(2007/10/03)
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- Excimer formation in oligo[2,5-bis(hexadecyloxy)-1,4-phenylene]s followed by fluorescence spectroscopy
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Using the steady-state and time-resolved fluorescence spectroscopy, the behavior of "hairy-rod" oligo- and poly[2,5-bis(hexadecyloxy)-1,4-phenylene]s in tetrahydrofuran solutions was investigated. The materials were prepared by the Yamamoto coupling reaction using zinc as a reducing metal, the nickel(II)/triphenylphosphine complex as a catalyst, and 2,2′-bipyridine as a coligand. The appropriate oligomer fractions were separated by fractional precipitation and characterized by GPC and end group analysis. The fluorescence quantum yield of oligomers and polymers increased with their increasing conjugation length. The fluorescence emission spectra of polymers and longer oligomers exhibited one emission maximum at 390 nm with a single-exponential decay and fluorescence lifetimes (τ) around 1 ns. The substitution in positions 2 and 5 forces the adjacent backbone benzene units out of the plane, which results in twist angles 60-80°, and the bulky substituents exclude the cofacial sandwich-type configuration necessary for excimer formation. However, with shorter oligomers, another emission band at 460 nm appeared. Fluorescence decays at 460 nm were found to be double-exponential with longer excited-state lifetimes [e.g. τ1 = 6.9 ns (76%), τ2 = 2.4 ns (24%)]. With shorter oligomers (dimer, trimer), we assume a sandwich-type configuration with sufficiently close interchain distance and hence the excimer can form. Hydrophobic interactions of long aliphatic side chains in a polar medium play an important role in the excimer formation.
- Vyprachticky, Drahomir,Cimrova, Vera,Machova, Lund'ka,Pokorna, Veronika
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p. 1473 - 1489
(2007/10/03)
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- The synthesis of natural acetylenic compounds from Stereum hirsutum
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The regioselective synthesis of two new acetylenic compounds, sterehirsutinol (1) and sterehirsutinol (2), isolated recently from culture medium of the fungus Stereum hirsutum, is reported.
- Fkyerat, Abdellatif,Dubin, Guy-Marie,Tabacchi, Raffaele
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p. 1418 - 1422
(2007/10/03)
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- The preparations and some properties of mixed aryl-thienyl oligomers and polymers
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The syntheses by transition metal coupling reactions of a large number of oligomers constructed from benzene and thiophene rings are described. The first use of arylcadmium chlorides for such coupling reactions is reported. The routes chosen allow for rational variation in the modes of linkage, the substitution and the proportions of the two units. The benzene and thiophene rings are always joined in a known order and may bear a wide variety of regularly spaced functional groups. Additionally the shape of the oligomers may be varied at will. In all cases p-type doping with iodine or ferric chloride leads to large enhancements in conductivity.
- Pelter, Andrew,Jenkins, Ieuan,Jones, D. Elfyn
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p. 10357 - 10400
(2007/10/03)
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- Synthese eines optisch aktiven Poly(para-phenylen)-Leiterpolymers
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Keywords: Chiralitaet; Circulardichroismus; Polymere
- Fiesel, Rainer,Huber, Joachim,Scherf, Ullrich
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p. 2233 - 2234
(2007/10/03)
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- Interactions in crystals. 76. Single crystal structures of 2,5-bis(trimethylsilyl)-hydroquinone without solvent and with either dimethoxyethane or dioxane: Some insight into the manifold of hydrogen bridge bonding of the same molecule
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2,5-Bis(trimethylsilyl)hydroquinone (monoclinic, C2/c, Z=12) forms infinite strings in x-direction, in which alternatingly on both sides each three molecules are bound together by three phenolic H bridges in a triangular arrangement. In the dimethoxyethane solvate (triclinic, P1, Z=1) with a 3:2 ratio of phenol to ether, the infinite strings are interlinked by twice-OH...O bonded H3COCH2CH2OCH3 chelate molecules. The smallest subunit with only two Hydrogen bonds -OHO...(CH2CH2)O informed in the monomeric 2:1 dioxane solvate (triclinic, P1, Z=1), The structural details of the different H bridge bonds are discussed based both on a statistical analysis from the Cambridge Structural Database as well as on PM3-calculated enthalpies of formation starting from the crystal structures determined. Johann Ambrosius Barth 1996.
- Bock, Hans,Nick, Sabine,Naether, Christian,Bats, Jan W.
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p. 363 - 373
(2007/10/03)
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- Bromination of Phenols by Use of Benzyltrimethylammonium Tribromide
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The reaction of phenols with benzyltrimethylammonium tribromide in dichloromethane-methanol for 1 h at room temperature gave polybromophenols in good yields.
- Kajigaeshi, Shoji,Kakinami, Takaaki,Tokiyama, Hajime,Hirakawa, Takahiro,Okamoto, Tsuyoshi
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p. 627 - 630
(2007/10/02)
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