Synthesis,electrical and optical properties of multifunctional poly[2-(2-ethyl-hexyloxy)-1,4-phenylenevinylene]

Summary Branched monoalkoxy-substituted poly[2-(2-ethylhexyloxy)-1,4-phenylenevinylene] (EH-PPV) was prepared in thin films via the water-soluble precursor technique and solution elimination method. These precursor polymer films could be stretched up to 8 times, and the drawn films of the EH-PPV could be doped with I₂ and FeCl₃ to give conductivities of 5.28x10^-3 and 0.56 S/cm, respectively. The third-order nonlinear optical susceptibility of the polymer was determined by using third harmonic generation (THG) method at 1907 nm, fundamental wavelength. Measured ⁽³⁾(–3; ,,) value was 3.8x10^-12 esu. The maximum emission wavelength of EH-PPV film in photoluminescence spectrum was 560 nm, corresponding to the yellowish red color.     

Synthesis and characterization of the soluble luminescent poly[2-decyloxy-5-(4’-ethoxyphenyl)-1,4-phenylenevinylene]

Summary A new soluble luminescent poly[2-decyloxy-5-(4^′-ethoxyphenyl)-1,4-phenylene-vinylene] (DEP-PPV) is prepared by the dehydrohalogenation of 1,4-bis(bromo-methyl)-2-decyloxy-5-(4^′-ethoxyphenyl) benzene in this study. The structure and properties of the DEP-PPV are examined by ¹H NMR, FT-IR, UV/VIS, TGA, photoluminescence (PL), and electroluminescence (EL) analyses. The incorporation of a decyloxy substituent in the 2-position of phenylene ring makes the DEP-PPV soluble in organic solvents and eliminates tolan-bis-benzyl structure defects. The energy band gap of DEP-PPV in tetrahydrofuran is 2.36 eV. The PL peak of DEP-PPV solution shifts to higher wavelength as the solution concentration increases. The PL spectrum of the DEP-PPV film shows a peak at 546 nm and the one of the pristine PPV film does at 540 nm. This red shift of PL peak for the DEP-PPV as compared with that for the PPV indicates that the incorporation of a conjugated ethoxyphenyl group on the phenylene ring can increase the conjugation length of phenylenevinylene units in the DEP-PPV. With the DEP-PPV acting as a light-emitting polymer, a device is fabricated with a sequential lamination of ITO/PEDOT/DEP-PPV/Ca/Ag. The EL spectrum of the device shows a maximum emission at 530 nm, which corresponds to the yellowish-green light. The turn-on voltage of the device is about 16 V. Its maximum brightness is 46 cd/m² at a voltage of 18 V.     

Electrical and third-order nonlinear optical properties of poly(2-fluoro-1,4-phenylenevinylene) and its copolymers

Summary Poly(2-fluoro-1,4-phenylenevinylene), PFPV, and its copolymers have been synthesized via water soluble precursor route and their electrical and optical propreties were measured. It seems that electron-withdrawing fluorine substituent on phenylene ring increases the band-gap of PFPV and it affects electrical and optical properties. The conductivity values of FeCl₃-doped drawn polymer films ranged from 10^-1 to 10¹ Scm^-1 depending on their composition, and were 10 times larger than those of undrawn ones. The ⁽³⁾ value for undrawn PFPV, using THG technique at 1907nm fundamental wavelength, was 4.76x10^-12 esu.     

Synthesis and two-photon absorption properties of 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles

Two symmetrical 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles that exhibit strong two-photon absorption and enhanced two-photon excited fluorescence were designed and synthesized based on “push-core-pull-core-push” molecules built from embedding electron-transporting 1,3,4-oxadiazole in aromatic conjugated system through Wittig–Horner reaction. Pumped by nanosecond laser at 800 nm, strong up-conversion emissions with the central wavelength at 507 nm (green) of 2,5-bis[4-(2-N,N-diphenylaminostyryl)phenyl]-1,3,4-oxadiazole and 475 nm (blue) of 2,5-bis[4-{2-(3-N-ethylcarbazolyl)vinyl}phenyl]-1,3,4-oxadiazole in the solution of CHCl₃ have been observed. Their two-photon absorption cross-sections obtained by nonlinear transmission method are 107 × 10⁻⁴⁸ cm⁴ s photon⁻¹ and 66 × 10⁻⁴⁸ cm⁴ s photon⁻¹. A very effective energy transfer from the excited terminal units to the π-conjugated bridging units of the 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles is the dominant contribution to the two-photon absorption.     

Conformational structure and aggregation behavior of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] in toluene/nonane solutions

We identified the conformational structure, aggregation behavior and photophysical properties of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) in various toluene/nonane solutions dependent on nonane content. In dilute solution region (e.g., below the overlap concentration, c*), static light scattering (SLS) revealed that the stiffness of MEH-PPV decreased as nonane content was increased, attributed to a stronger interaction force between MEH-PPV backbones. However, MEH-PPV chains presented a more extended-wormlike conformational structure in toluene. Therefore, a looser intermolecular micellelike aggregates occurred easily between the ether side chains of MEH-PPV at the concentration exceeded the overlapping concentration in toluene and toluene/nonane solutions. Nevertheless, at higher nonane content, the micellelike aggregates were became highly compacted by the π–π complex force between MEH-PPV backbones, dominating the dynamic behaviors and photophysical properties of MEH-PPV in toluene/nonane solution. These results proved that two types of segmental association with distinct stability were identified for the MEH-PPV/toluene/nonane solutions upon prolonged aging. The highly stable, which could not be disrupted by heating, was attributed to the interaction force between ether side chains of MEH-PPV in both solutions. Other type was a weaker affinity force through π–π complex, which could be disrupted thermally, making the micellelike aggregates more compact to form the network structure in MEH-PPV-enriched at higher nonane content.     

Synthesis and properties of poly[2,6-(p-phenylvinyl)-4-(4'-octyloxybiphenyl-4-yl)quinoline]

Summary A novel polyquinoline (PQDBP8) containing the pendent 4'-octyloxybiphenyl group in the 4-position of the quinoline ring was prepared by the acid-catalyzed polymerization (Friedl?nder quinoline synthesis) of 1-(4-{2-[4-amino-3-(4'-octyloxybiphenyl-4-carbonyl)-phenyl]vinyl}phenyl)ethanone (6). PQDBP8 showed highly thermal stability (T_d= 384 °C, T_g= 183 °C). PQDBP8 showed blue fluorescence in dilute solution (λ_max= 449 nm) and green fluorescence in solid state (λ_max= 494, 540 nm) due to excimer formation. EL spectrum of PQDBP8 lies in the green region (λ_max= 572 nm) and PQDBP8/PVK blend film lies in the blue region (λ_max= 446 nm). Received: 16 February 1999/Revised version: 20 April 1999/Accepted: 26 April 1999     

Synthesis and characterization of 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles with two-photon fluorescence properties

Four novel 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles that exhibit strong two-photon absorption and enhanced two-photon excited fluorescence were designed and synthesized based on push-core-pull-core-push  molecules built from embedding electron-transporting 1,3,4-oxadiazole in aromatic conjugated system through Wittig-Horner reaction. Their chemical structures were determined to show trans-vinylene character according to infrared (IR) and ¹H nuclear magnetic resonance (NMR) spectra. A very effective energy transfer from the excited units to the ?-conjugated bridging unit can enhance the two-photon absorption and two-photon fluorescence.     

Synthesis and properties of organosoluble polyimides based on 1,1-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]cyclohexane

New aromatic diamine with cyclohexane cardo group substituted with trifluoromethyl group in the side chain, 1,1-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]cyclohexane (II), was prepared through the nucleophilic substitution reaction of 1,1-bis(4-hydroxyphenyl)cyclohexane and 2-chloro-5-nitrobenzotrifluoride in the presence of potassium carbonate, to yield the intermediate dinitro compound I, followed by catalytic reduction with hydrazine and Pd/C to afford the diamine II. Fluorinated polyimides (IVa-g) were prepared from the II with various aromatic dianhydrides via thermal or chemical imidization of poly(amic acid). These polyimides had inherent viscosity ranging from 0.72 to 1.16 dl/g and showed excellent solubility in a variety of organic solvents. They were soluble in a concentration of 10% in the amide polar solvent, and 1-5% in the other testing solvents. IV films showed good mechanical properties, excellent thermal stability. The 10% weight loss temperature was above 476 °C in nitrogen or air, and the glass transition temperature was recorded at 214-278 °C. In comparison of the IV series with the analogous nonfluorinated polyimides (V series) based on 1,1-bis[4-(4-aminophenoxy)phenyl]cyclohexane (II′), IV series revealed better solubility, lighter-colored and lower dielectric constants and moisture absorptions. Their films had cut-off wavelengths in the range of 364-414 nm, b^* value (a yellowness index) ranging from 3.3 to 66.3, dielectric constants of 3.02-3.55 (1 MHz), with moisture absorption of 0.16-0.36 wt%.     

4,4'-二(苯基异丙基)二苯胺的合成工艺研究

以二苯胺和α-甲基苯乙烯为原料合成了4,4’-二(苯基异丙基)二苯胺,研究了合成工艺参数,得到最优工艺条件.红外谱图证明了产物的正确性.放大实验结果表明,最佳合成条件下的收率达到95.2％.     

Synthesis and characterization of 2,5-bis[4-(2-arylvinyl) phenyl]-1,3,4-oxadiazoles with two-photon fluorescence properties

Four novel 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles that exhibit strong two-photon absorption and enhanced two-photon excited fluorescence were designed and synthesized based on “push-core-pull-core-push” molecules built from embedding electron-transporting 1,3,4-oxadiazole in aromatic conjugated system through Wittig-Horner reaction. Their chemical structures were determined to show trans-vinylene character according to infrared (IR) and ¹H nuclear magnetic resonance (NMR) spectra. A very effective energy transfer from the excited units to the π-conjugated bridging unit can enhance the two-photon absorption and two-photon fluorescence. __________ Translated from Journal of Southeast University (Natural Science Edition), 2006, 36(5): 795–798 [译自: 东南大学学报 (自然科学版)]     

2-甲氧亚胺基-2-[2-(2-甲基苯氧甲基)苯基]乙腈合成研究

采用苯酞为起始原料,合成得到标题化合物,并探讨了影响各步反应的因素.4步反应总收率51.1％,各步反应产物利用IR、1 HNMR进行了结构表征.1HNMR表征表明,标题化合物为E、Z异构体混合物,比例约为2∶1.     

合成1-[4-(二甲氨基)苯基]马来酰亚胺的新方法

介绍了以生产香兰素主要副产物Ｎ，Ｎ—二甲基对苯二胺为原料，通过缩合、闭环等反应，以７５％总收率合成了标题化合物。元素分析、色谱－质谱联用、红外光谱及′ＨＮＭＲ谱等鉴定结果证明，该合成的化合物是一种纯度高，熔点为１５４℃～１５５℃的红棕色针状晶体，分子结构式为：     

2-苯基-4,6-[2-羟基-4-(哌啶氧基羰基甲氧基)苯基-1,3,5-均三嗪的合成与表征

以三聚氯氰为起始原料,通过与格氏反应、Friedel-Craft反应、醚化反应及酯交换反应合成了2个含受阻胺结构的新型三嗪类双功能光稳定剂——2-苯基-4,6-[2-羟基-4-(2,2,6.6-四甲基哌啶氧基羰基甲氧基)苯基]-1,3,5-均三嗪（Ⅳa）及2-苯基-4,6-[2-羟基-4-(1,2,2,6.6-五甲基哌啶氧基羰基甲氧基)苯基]-1,3,5-均三嗪（Ⅳb）,收率分别为37.6%和38.1%;用MS、H1-NMR和IR确定了目标产物的结构;测试了紫外吸收性能。结果显示,目标产物在270～400nm有较强吸收,Ⅳa和Ⅳb最大摩尔吸收系数分别为6.6513?04（276nm）,2.8374?04（339nm）L?mol-1? cm-1;6.4359?04（276nm）,2.6483?04（339nm）L?mol-1? cm-1     

3-[4-(2,3-环氧丙氧基)苯基]丙酸甲酯的合成

对羟基苯丙酸甲酯与环氧氯丙烷，以碳酸钾为催化剂，PEG400为助催化剂，回流反应24小时，制得标题化合物，收率45％，产物径^1HNMR，^13CN0MR，IR确认。研究表明，要获取高产率，环氧氯丙烷应大大过量。一旦回流平稳，反应即按相同的机理进行。PEC400的加入可大大增加目标化合物的含量，同时大大降低产物中羟基化合物的含量，使提纯步骤易于进行。     

磷光配体3-[4-(2-吡啶基)苯基]-9-(4-氟苯基)-9H-咔唑的合成

以对溴苯胺为原料,经重氮化、Gomberg-Bachmann偶联、硼酸化反应得到4-(2-吡啶基)苯硼酸;再与对氟苯基取代的咔唑,通过四(三苯基磷)钯催化,于90℃进行Suzuki偶联合成出标题磷光配体,收率82.03%。对目标物用核磁共振氢谱和元素分析进行了表征,并测得它在二氯甲烷中的紫外吸收光谱和荧光光谱。由于受咔唑基团的影响,磷光配体最大吸收峰波长红移56 nm,且吸收的强度增加,Stokes位移154 nm,相对荧光量子效率为0.17。     

2,2'-双[4-(3-氨基苯氧基)苯基]丙烷的合成

提出了以间二硝基苯和双酚A为原料经缩合和水合肼催化还原合成聚酰亚胺的单体2,2'-双[4-(3-氨基苯氧基)苯基]丙烷的新工艺,考察了各类工艺条件对目标产物收率的影响,得到最适宜反应条件,在优化条件下,总收率为85.5%.HPLC面积归一法测定目标产物纯度为99.97%,并用元素分析和红外光谱对目标产物进行了表征.     

光固化剂双[(4-二苯硫鎓)苯]硫醚-双-六氟磷酸盐的合成

合成了一种带有两个三苯基硫鎓盐的新型阳离子光固化剂双[(4-二苯硫鎓)苯]硫醚-双-六氟磷酸盐.以二苯硫醚为主要原料,经过氧化得到了二苯亚砜.然后,二苯亚砜与二苯硫醚在酸的催化下反应制备了双[(4-二苯硫鎓)笨]硫醚-双-六氟磷酸盐.收率75%.     

2,2′-双[4-(3-氨基苯氧基)苯基]丙烷的合成

提出了以间二硝基苯和双酚A为原料经缩合和水合肼催化还原合成聚酰亚胺的单体2,2′-双[4-(3-氨基苯氧基)苯基]丙烷的新工艺,考察了各类工艺条件对目标产物收率的影响,得到最适宜反应条件,在优化条件下,总收率为85.5%。HPLC面积归一法测定目标产物纯度为99.97%,并用元素分析和红外光谱对目标产物进行了表征。