Solution processable polyamides containing thiazole units and thioether linkages with high optical transparency,high refractive index,and low birefringence

A series of new organic‐soluble polyamides (PAs) bearing flexible thioether linkages and heteroaromatic thiazole units were synthesized from a novel thioether‐bridged diamine monomer (DA) and various commercially available aromatic dicarboxylic acids (1–5) via a direct polycondensation method. The resulting polymers were obtained in high yields and possessed inherent viscosities in the range of 0.41–0.80 dL g^?1. All of the polymers were amorphous in nature, exhibited good solubility and could be easily dissolved in amide‐type polar aprotic solvents and even dissolved in less polar solvents (e.g., tetrahydrofuran, pyridine, and acetone). They showed excellent thermal stability with glass transition temperatures between 207 and 239 °C and 10% weight loss temperatures in excess of 424 °C in nitrogen and 469 °C in air atmosphere. The optical transmittances of the PA films at 450 nm were higher than 85% for the thickness of ～10 μm. The combination of the thiazole moieties and flexible thioether linkages provided PAs with high average refractive indices (n_av) of 1.7414–1.7542 and low birefringences (Δn) of 0.0061–0.0087 at 632.8 nm. In particular, the n_av of PA‐5 derived from DA and 2,2′‐dithiodibenzoic acid exhibited the highest refractive index (1.7542) in the high refractive index PAs. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3505–3515     

The synthesis of metal-free octaazaphthalocyanine derivatives containing bulky phenoxy substituents to prevent self-association

Octaazaphthalocyanines with eight phenoxy groups in the peripheral sites are prepared for the first time using the simple synthetic procedure of heating their pyrazine-2,3-dicarbonitrile precursor in quinoline. This process avoids transetherification, which has hindered previous attempts at preparing metal-free octaazaphthalocyanines. Metal-containing derivatives were also prepared by adding the appropriate metal salt to the reaction mixture. Bulky iso-propyl or phenyl groups at the 2,6-positions of the phenoxy substituents prevent self-association of the octaazaphthalocyanine cores even in the solid state.     

Synthesis,characterization, and electroluminescence of polyfluorene copolymers containing T‐shaped isophorone derivatives

We have successfully synthesized a series of new fluorene‐based copolymers, poly[(9,9‐bis(4‐octyloxy‐phenyl)fluorene‐2,7‐diyl)‐co‐[2(3{2[4(2{4[bis(bromophenyl‐4yl) amino]phenyl}vinyl)‐2,5‐bisoctyloxyphenyl]vinyl}‐5,5‐dimethyl‐cyclohex‐2‐enylidene)malononitrile] (PFTBMs), with varying molar ratios of the low‐energy band gap comonomer, 2(3{2[4(2{4[bis(4‐bromophenyl)amino]phenyl}vinyl)‐2,5‐bisoctyloxyphenyl]vinyl}‐5,5‐dimethyl‐cyclohex‐2‐enylidene)malononitrile (BTBM). To prepare BTBM (which has a T‐shaped structure) from triphenylamine, dialkoxy phenyl, and isophorone, we introduced three individual segments of an isophorone derivative containing two cyanide groups at the carbonyl position, a dialkoxy phenyl group for increased solubility, and a triphenyl amine for effective charge transfer. Furthermore, we introduced vinyl linkages between each segment to increase the length of π‐conjugation. The synthesized polyfluorene copolymers with the BTBM, PFTBMs, were synthesized via palladium‐catalyzed Suzuki coupling reactions. The photoluminescence emission spectra of the synthesized polymers in solution did not show significant energy transfer from PBOPF segments to the BTBM units. Light‐emitting devices based on these polymers were fabricated with an indium tin oxide/poly(3,4‐ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/polymers/Balq/LiF/Al configuration. Examination of the electroluminescence emission of the synthesized polymers showed that the maximum wavelength shifted continuously toward long wavelengths with as the number of BTBM units in the polymer main chain was increased. In particular, a device using PFTBM 05 exhibited a maximum brightness of 510 cd/m² and a maximum current efficiency of 0.57 cd/A. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 82–90, 2010     

Polyfluorenes containing tetraphenylthiophene segments: Synthesis,photophysics, and electroluminescence

2,5‐Bis(4‐bromophenyl)‐3,4‐diphenylthiophene was synthesized from benzyl chloride and sulfur and through the subsequent bromination of the intermediate 2,3,4,5‐tetraphenylthiophene. It was condensed with 2,7‐dibromo‐9,9‐dihexylfluorene via a nickel‐mediated Yamamoto coupling reaction to afford a new series of statistical copolymers with various compositions. In addition, poly(9,9‐dihexylfluorene) (PF) was synthesized under the same conditions for comparison. All the polymers were soluble in common organic solvents such as tetrahydrofuran (THF), chloroform, and dichloromethane. Their glass‐transition temperatures increased with an increase in the tetraphenylthiophene (TPT) content in the polymers, and they were 63–149 °C. The solutions of the polymers in THF emitted intense blue light with a photoluminescence maximum at 418–440 nm and quantum yields of 0.32–0.62. Thin films of the polymers with TPT fractions lower than 20 mol % emitted blue‐green light with two well‐resolved peaks at 445 and 520 nm and an optical band gap of about 2.85 eV. A thin film of the polymer with aTPT fraction of 50 mol % emitted pure blue light with a maximum at 419 nm and an optical band gap of 3.28 eV. An enhancement of the light‐emitting‐diode brightness by a factor of ～8 with respect to that of PF was achieved in apolymer containing 5 mol % TPT. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4015–4026, 2006     

Polyfluorenes containing pyrazine units:Synthesis,photophysics and electroluminescence

A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfer was observed in both thin film and solution.Compared with the lowest occupied molecular orbital (LUMO) energy level of the polyfluorenes homopolymer (PFO),the lower LUMO energy levels of copolymers indicated that the introduction of the BY unit would be benefit to electron injection.The turn-...     

Doubly charged ion mass spectra: V—Oxygen containing hydrocarbons

Doubly charged ion mass spectra were obtained for 46 low molecular weight oxygen containing compounds. A double focusing Hitachi RMU-7L mass spectrometer, operated at 3.2 kV accelerating voltage, was used to measure spectra for aliphatic alcohol, ketone, ether, aldehyde, ester and acid molecules, as well as several aromatic oxygen containing compounds. In general, the spectra were dominated by fragment ions which resulted from extensive H loss and C? C bond rupture as well as O elimination from the doubly charged molecular ions. Total product ion intensities from doubly charged ion spectra of aliphatic oxygen containing compounds were approximately 1% of the corresponding total ion intensity in the benzene doubly charged ion spectrum. Appearance energies for forming prominent doubly charged molecular and fragment ions were determined. Measured values ranged from 26 to 45 eV. A geometry optimized quantum mechanical SCF treatment was used to compute the energies, charge densities and structures for several of these oxygen containing doubly charged ions.     

Design,synthesis and antiviral activities of chalcone derivatives containing pyrimidine

A series of chalcone derivatives (T1-T23) containing pyrimidine were synthesized, characterized, and assessed for their antiviral activity against tobacco mosaic virus (TMV) activities. Most target compounds displayed better antiviral activities against TMV than commercial ningnanmycin. Among them, the EC₅₀ value of curative activities of compounds T1, T7, T9 and T19 (219.2, 228.2, 279.9 and 234.9 μg/mL, respectively) were superior to that of ningnanmycin (320.1 μg/mL). In addtion, the EC₅₀ value of protective activities of compounds T5, T9, T19 and T23 (235.0, 220.0, 199.5 and 187.2 μg/mL, respectively) were superior to that of ningnanmycin (307.4 μg/mL). Then, the antiviral mechanism of T19 and TMV coat protein (TMV-CP) was preliminarily investigated by microscale thermophoresis (MST) and molecular docking technology. The results showed that T19 had a strong binding affinity for TMV coat protein, and its dissociation constant (K_d) was 0.00310 ± 0.000916 μM, which was superior to ningnanmycin(0.165 ± 0.0799 μM). This study suggests that chalcone derivatives containing pyrimidine could be used as novel antiviral agents for controlling the plant viruses.     

Side chain-dependent binding of antitumor indoloquinoxaline derivatives to DNA: comparative spectroscopic and viscometric measurements

NCA0424 (1) and its side chain positional isomer, NCA0465 (2), are indoloquinoxaline derivatives with potent antitumor activity. To investigate the effect of side chain position for binding with DNA, the interactions of 2 with various B-form DNAs were studied by spectroscopic (circular dichroism (CD), fluorescence and UV) and viscosity measurements and were compared with those of 1. The binding preference for the base sequence was different in each case. The CD spectra showed that 2 formed an asymmetric binding of indoloquinoxaline ring with adenine in DNA, whereas such a base selectivity was not found with 1. The binding features are discussed based on association constants and thermodynamic parameters, indicating the importance of the side chain position for binding specificity for DNA.     

Tuning the solid-state luminescence of BODIPY derivatives with bulky arylsilyl groups: synthesis and spectroscopic properties

Boron dipyrromethenes (BODIPYs) with bulky triphenylsilylphenyl(ethynyl) and triphenylsilylphenyl substituents on pyrrole sites were prepared via Hagihara-Sonogashira and Suzuki-Miyaura cross-coupling with ethynyl-terminated tetraphenylsilane and boronic acid-terminated tetraphenylsilane. The chromophores are designed to prevent intermolecular π-π stacking interaction and enhance fluorescence in the solid state. Single crystals of 1?a and 2?b for X-ray structural analysis were obtained, and weak π-π stacking interactions of the neighboring BODIPY molecules were observed. Spectroscopic properties of all of the dyes in various solvents and in films were investigated. Triphenylsilylphenyl-substituted BODIPYs generally show more pronounced increases in solid-state emission than triphenylsilylphenyl(ethynyl)-substituted BODIPYs. Although the simple BODIPYs do not exhibit any fluorescence in the solid state (Φ=0), arylsilyl-substituted BODIPYs exhibit weak to moderate solid-state fluorescence with quantum yields of 0.03, 0.07, 0.10, and 0.25. The structure-property relationships were analyzed on the basis of X-ray crystallography, optical spectroscopy, cyclic voltammetry, and theoretical calculations.     

Configurationally defined sexi- and octinaphthalene derivatives: synthesis and optical properties

The copper mediated oxidative coupling of optically active quaternaphthalenes having a 2-hydroxynaphthyl moiety gave configurationally defined optically active octinaphthalenes. The absolute configuration was determined by comparison with products of [6+2] coupling. The CD spectra of bi-, ter-, quater-, sexi- and octinaphthalenes suggested that the absolute configuration of the chiral axis could be deduced from the intensity of their Cotton effects.     

Giant extended pi-conjugated dendrimers containing the 10,15-dihydro-5H-diindeno[1,2-a;1',2'-c]fluorene chromophore: synthesis, NMR behaviors, optical properties, and electroluminescence

This paper reports the facile synthetic strategy of a series of novel pi-conjugated dendrimers (G0 and G1) based on 10,15-dihydro-5H-diindeno[1,2-a;1',2'-c]fluorene (truxene) in which the benzene cores are generated "in-situ" from acetyl aromatics by the acid-promoted cyclotrimerizations. The unique NMR behaviors, physical properties, and electroluminescence device applications are also presented. Besides the purity, the structure, and the confirmation of the successful formation and isolation of desired compounds by clear assignments of every molecule by (1)H and (13)C and 2D NMR characterizations, several astonishing NMR behaviors have been observed in various solvents. For 1, chemical shift values belonging to H-2' of hexyl substituents move to the most upfield; however, such chemical shift values move from 0.48 to 0.85 ppm when pyridine-d(5) or benzene-d(6) is used as solvent. Our dendrimers as the emissive layers in organic light-emitting diodes gave blue-green light with an external quantum efficiency up to 0.16% both for G0 and for G1 in nitrogen, respectively, which exhibit unique electroluminescence spectra in comparison with their corresponding photoluminescence ones.     

Synthesis,optical properties,and electroluminescence of conjugated poly(p‐phenylenevinylene) derivatives containing 1,3,4‐oxadiazole and pyridine rings in the main chain

Three new poly(p‐phenylenevinylene) derivatives—PO, POD, and POP—with oxadiazole and pyridine rings along the main chain were synthesized via Heck coupling. The polymers were amorphous and dissolved readily in common organic solvents. They showed relatively low glass‐transition temperatures (up to 42 °C) and satisfactory thermal stability. Solutions of the polymers emitted blue‐greenish light with photoluminescence (PL) emission maxima around 460 nm and PL quantum yields of 0.28–0.49. Thin films of the polymers displayed PL emission maxima at 461–521 nm, and their tendency to form aggregates was significantly influenced by the chemical structure. Light‐emitting diodes with polymers PO and POP, with an indium tin oxide/poly(ethylenedioxythiophene) (PEDOT)/polymer/Ca configuration, emitted yellow and green light, respectively, and this could be attributed to excimer emission. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3212–3223, 2004     

Semiconductivity,optical properties,and EPR spectra of phenothiazine derivatives in the solid state

The optical, EPR, and electrical properties of phenothiazine derivatives have been investigated as a function of R₂ substituents. Diffuse reflectance spectra show a charge transfer complex transition between 600 and 1100 nm. The EPR spectra show the existence of the radical cation with an unpaired electron per molecule; also there can be seen a dependence of the bandwidth on the R₂ substituents. Measurements of electrical conductivity show a semiconductor behavior in the studied temperature range; the values show as well a dependence of conductivity on R₂. The estimation of the drift mobility of charge carriers seems to indicate a hopping mechanism for the charge conduction.     

4-氟苯乙胺基准二维钙钛矿的合成及其电致发光与激光性能

设计并开发了一种兼具电致发光和光学增益性能的准二维钙钛矿材料。通过向三维钙钛矿CsPbBr₃中引入大体积阳离子4-FPEA⁺(4-氟苯乙胺),利用简易的溶液旋涂法,制备了不同n值量子阱混合分布的准二维钙钛矿薄膜。通过紫外可见吸收光谱和光致发光光谱证明调整4-FPEA⁺的添加量可以对量子阱的分布进行有效调控。结合扫描电子显微镜和原子力显微镜证明4-FPEA⁺的加入可以降低薄膜表面粗糙度。当4-FPEA⁺和CsPbBr₃的物质的量之比为0.6时,薄膜的发光强度最高。将该材料应用在发光二极管(light emitting diodes,LEDs)中,结合冠醚作为添加剂辅助钝化缺陷,实现了外量子效率(EQE)为0.98%的绿光LED器件。在激光性能方面,该材料在室温条件下的最低阈值为17.42μJ·cm^-2,增益系数为35 cm^-1。     

Synthesis of hydrocarbon polymers containing bulky dibenzobicyclic moiety by ROMP and their characteristic optical properties

The eight‐membered cyclic monomer, prepared by Diels–Alder reaction of 1,5‐cyclooctadiene and anthracene, polymerized via Ru‐catalyzed ring‐opening metathesis to efficiently afford high polymers (M_n up to 631,000). Unsaturated moieties in the main chain of the obtained polymer were hydrogenated with a homogeneous ruthenium catalyst in quantitative conversion, confirmed by ¹H‐NMR measurement. The self‐standing membranes were provided by casting the tetrahydrofuran solutions of both nonhydrogenated and hydrogenated polymers. The obtained membranes showed high transparency in the region of >300 nm with mechanical flexibility. Thermal gravimetric analysis revealed that both nonhydrogenated and hydrogenated polymers decomposed in two stages. The first‐stage decomposition starting at around 230 °C was caused by retro Diels–Alder reaction forming anthracene, proven by pyrolysis gas chromatography mass spectroscopy (GC‐MS) analyses. Mechanical grinding of the polymers induced the formation of anthracene in solid state, which transformed the polymer into blue‐luminescent materials under UV irradiation. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1392–1400     

Phosphine oxide-functionalized polyfluorene derivatives:Synthesis,photophysics,electrochemical properties,and electroluminescence performance

A series of phosphine oxide-functionalized polyfluorene derivatives,PFH-PO-40-1 (P1),PFH-PO-20-1 (P2),PFH-PO-10-1 (P3),and PFH-PO-1-1 (P4),were prepared via a palladium-mediated Suzuki cross-coupling reaction.The structures and purities of all polymers were fully characterized by 1H and 13C NMR,UV-vis and photoluminescent spectroscopy,gel permeation chromatography,and TGA/DSC.Their emission features showed single broad peaks at about 445 nm in film,compared with those in dilute solutions,which might be caus...     

32P-postlabelling and mass spectrometric methods for analysis of bulky, polyaromatic carcinogen-DNA adducts in humans.

There has been significant recent progress toward the development of human carcinogen-DNA adduct biomonitoring methods. 32P-Postlabelling is a technique which has found wide application in human studies. 32P-Postlabelling involves enzymatic preparation and labelling of DNA samples, followed by chromatographic separation of carcinogen-nucleotide adducts from unadducted nucleotides. Thin-layer ion-exchange and high-performance liquid chromatography (HPLC) have been utilized. This paper critically reviews 32P-postlabelling methods for analysis of bulky, polyaromatic carcinogen-DNA adducts and details a strategy to optimize this technique for monitoring human samples. Development of a human carcinogen biomonitoring method requires that the biomarker meet certain criteria: that the biomarker be responsive to exposures known to increase human cancer risk, to reductions in those exposures, and to the influence of metabolic differences. In addition, reliable samples must be available by non-invasive means. The ability of 32P-postlabelling to meet these criteria is traced in the literature and discussed. Identification of specific carcinogen-DNA adducts is a difficult task due to the low (femtomole) levels in human target tissues. Because co-chromatography in thin-layer chromatography (TLC) is generally not considered to be proof of chemical identity, both synchronous fluorescence and HPLC in conjunction with 32P-postlabelling and TLC are used to confirm the identity of specific carcinogen-DNA adducts in human samples. Mass spectrometry is a highly specific method, the sensitivity of which has been improved to the point which may allow its use to confirm the identity of carcinogen-DNA adducts isolated by 32P-postlabelling and other methods. The literature relating to the use of mass spectral techniques in carcinogen-DNA adduct analysis is reviewed.     

4-氟苯乙胺基准二维钙钛矿的合成及其电致发光与激光性能

设计并开发了一种兼具电致发光和光学增益性能的准二维钙钛矿材料。通过向三维钙钛矿CsPbBr₃中引入大体积阳离子4-FPEA⁺(4-氟苯乙胺),利用简易的溶液旋涂法,制备了不同n值量子阱混合分布的准二维钙钛矿薄膜。通过紫外可见吸收光谱和光致发光光谱证明调整4-FPEA₊的添加量可以对量子阱的分布进行有效调控。结合扫描电子显微镜和原子力显微镜证明4-FPEA⁺的加入可以降低薄膜表面粗糙度。当4-FPEA₊和CsPbBr³的物质的量之比为0.6时,薄膜的发光强度最高。将该材料应用在发光二极管(light emitting diodes,LEDs)中,结合冠醚作为添加剂辅助钝化缺陷,实现了外量子效率(EQE)为 0.98%的绿光LED器件。在激光性能方面,该材料在室温条件下的最低阈值为17.42 μJ·cm^-2,增益系数为35 cm^-1。     

The electronic structures and spectra of nonbenzenoid aromatic hydrocarbons containing the cyclopropenyl ring

The ground-state electronic properties and electronic spectra of triafulvene, I, triafulvalene, II, calicene, III, heptatriafulvalene, IV, benzocalicene, V, and dibenzocalicene, VI, have been studied by the semiempirical SCF CI LCAO--MO method which allows for bond order-bond length correlation at each iteration. The dependence of the resonance integral on bond length is scrutinized by trying to reproduce the properties of the ground and excited states in a series of reference compounds. For the bonds in the cyclopropenyl ring a new bond order-bond length relationship is proposed which allows for the fact that their components are bent. The calculated dipole moment and bond lengths of III and the predicted electronic spectra of III, V, and VI are in good agreement with the available experimental data.

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Zusammenfassung Grundzustand und Elektronenspektren von Triafulven, Triafulvalen, Calicen, Heptatriafulvalen, Benzocalicen und Dibenzocalicen wurden mittels eines semiempirischen SCF-Verfahrens mit Korrelation zwischen Bindungsordnung und -länge untersucht. Die Abhängigkeit des Resonanzintegrals von der Bindungslänge wurde bestimmt, indem Grund- und angeregte Zustände einer Reihe von Bezugssubstanzen zur Justierung herangezogen wurden. Für die Bindungen im Cyclopropylenring wird eine neue Beziehung zwischen Bindungsordnung und -länge vorgeschlagen, die den verzerrten -Komponenten Rechnung trägt. Die berechneten Dipolmomente und Bindungslängen von Calicen und die Spektren aller drei Calicene stimmen befriedigend mit dem Experiment überein.

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Résumé La méthode SCF-CI-LCAO--MO avec variation de la longueur de liaison en fonction de l'indice de liaison à chaque itération, a été utilisée pour l'étude des propriétés électroniques de l'état fondamental et du spectre des composés suivants: I triafulvène, II triafulvalène, III calicène, IV heptatriafulvalène, V benzocalicène, VI dibenzocalicène. La dépendance à la longueur de liaison de l'intégrale de résonance est sondée par ajustement à l'expérience de propriétés moléculaires. Pour le cyclopropylène une nouvelle relation entre longueur et indice de liaison est proposée pour tenir compte de ce que les composantes sont courbes. Le moment dipolaire et les longueurs de liaison de III et les spectres électroniques de III, V et VI sont prévus en bon accord avec les données expérimentales disponibles.