- Synthesis, morphology, and properties of poly(3- hexylthiophene)-block- poly(vinylphenyl oxadiazole) donor-acceptor rod-coil block copolymers and their memory device applications
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Novel donor-acceptor rod-coil diblock copolymers of regioregular poly(3- hexylthiophene) (P3HT)-block-poly(2-phenyl-5-(4-vinylphenyl)-1,3,4-oxadiaz- ole) (POXD) are successfully synthesized by the combination of a modified Grignard metathesis reaction (GRIM) and atom transfer radical polymerization (ATRP). The effects of the block ratios of the P3HT donor and POXD pendant acceptor blocks on the morphology, field effect transistor mobility, and memory device characteristics are explored. The TEM, SAXS, WAXS, and AFM results suggest that the coil block fraction significantly affects the chain packing ofthe P3HT block and depresses its crystallinity. The optical absorption spectra indicate that the intramolecular charge transfer between the main chain P3HT donor and the side chain POXD acceptor is relatively weak and the level of order of P3HT chains is reduced by the incorporation of the POXD acceptor. The field effect transistor (FET) hole mobility of the system exhibits a similar trend on the optical properties, which are also decreased with the reduced ordered P3HT crystallinity. The low-lying highest occupied molecular orbital (HOMO) energy level (-6.08 eV) of POXD is employed as charge trap for the electrical switching memory devices. P3HT-b-POXD exhibits a nonvolatile bistable memory or insulator behavior depending on the P3HT/POXD block ratio and the resulting morphology. The ITO/P3HT44-b-POXD18/Al memory device shows a non-volatile switching characteristic with negative differential resistance (NDR) effect due to the charge trapped POXD block. These experimental results provide the new strategies for the design of donoracceptor rod-coil block copolymers for controlling morphology and physical properties as well as advanced memory device applications.
- Fang, Yi-Kai,Liu, Cheng-Liang,Li, Chaoxu,Lin, Chih-Jung,Mezzenga, Raffaele,Chen, Wen-Chang
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- Silicon-based carbazole and oxadiazole hybrid as a bipolar host material for phosphorescent organic light-emitting diodes
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A silicon-based bipolar compound, 2-(4-((4-(9H-carbazol-9-yl)phenyl)dimethylsilyl)phenyl)-5-phenyl-1,3,4-oxadiazole (COHS), was designed and prepared as a host material for phosphorescent organic light-emitting diodes (OLEDs). The conjugated analogue of COHS, 2-(4′-(9H-carbazol-9-yl)biphenyl-4-yl)-5-phenyl-1,3,4-oxadiazole (COH), was also prepared to investigate their structure–property relationships. Thermal-, photophysical- and electrochemical properties as well as their single-crystal X-ray structures were studied for COHS and COH. The central silicon atom in COHS successfully disconnected the electronic communication between the carbazole and oxadiazole groups, resulting in relatively high triplet energy of ca. 2.71?eV, which were capable of hosting green phosphorescent emitters. DFT calculations were conducted to investigate the electronic structures of COHS and COH, and the results showed good correlation to experimental results. Finally, COHS and COH were used as a bipolar host material for a green phosphorescence organic light-emitting diode (PHOLED) devices with Ir(ppy)3 (tris[2-phenylpyridinato-C2,N]iridium(III)) as a dopant. The resulting device with COHS (device I) showed higher performance than the device with COH (device II), exhibiting high efficiencies and low-efficiency roll-off. Device I achieved maximum external quantum efficiencies (EQE) of 15.8%, whereas device II exhibited a relatively lower EQE of 13.0%.
- Lee, Ah-Rang,Lee, Jiwon,Lee, Jiewon,Han, Won-Sik
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- Improving the electroluminescence performance of donor-acceptor molecules by fine-tuning the torsion angle and distance between donor and acceptor moieties
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The torsion angle and distance between the donor (D) and the acceptor (A) are two important factors in determining the photoluminescence and electroluminescence properties of twisted D-A type organic molecules. Here, two new D-A compounds, 2-(10-butyl-10H-phenothiazin-3-yl)-5-phenyl-1,3,4-oxadiazole (PO) and 2-(4-(10-butyl-10H-phenothiazin-3-yl)phenyl)-5-phenyl-1,3,4-oxadiazole (PPO), were designed and synthesized to tune the torsion angle and distance between D and A moieties, and their photophysical and electroluminescence properties were investigated. The D-A type molecule PO has a planar conformation, whereas the D-π-A type molecule PPO has a twisted conformation because of the insertion of the phenyl bridge between the donor and the acceptor. Therefore, the charge transfer (CT) of PPO is much stronger than that of PO, and the singlet exciton yield of PPO may be higher than that of PO. On the other hand, the introduction of a phenyl unit can also improve the photoluminescence quantum efficiency (doped film ΦPL ≈ 70%). As a result, the PPO-doped device showed better device performance than PO. The device based on PPO as an emitter exhibited stable and high luminous efficiency (15.2 cd A-1, corresponding to an external quantum efficiency of 5.4%), which is increased by about 1.05 fold as compared to the device based on PO as an emitter (luminous efficiency 7.4 cd A-1 and external quantum efficiency 2.9%).
- Qiu, Xu,Xue, Shanfeng,Wu, Yongjin,Chen, Mingshuai,Sun, Qikun,Yang, Wenjun
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- Highly efficient yellow phosphorescent OLEDs based on two novel bipolar host materials
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Two bipolar host materials, N1-(naphthalen-1-yl)-N1,N4-diphenyl-N4-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl)naphthalene-1,4-diamine (NONP) and N1-(naphthalen-1-yl)-N1,N4-diphenyl-N4-(3-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl)naphthalene-1,4-diamine (NONM), comprising a hole-transporting N1-(naphthalen-1-yl)-N1,N4-diphenylnaphthalene-1,4-diamine (NPNA2) donor and an electron-transporting 1,3,4-oxadiazole (OXD) acceptor at different phenyl bridge positions, have been synthesized. NONP (glass transition temperature Tg= 127°C) and NONM (Tg= 105°C) exhibit high morphological stability. The theoretical calculations on both hosts show that the HOMOs (highest occupied molecular orbitals) are mainly dispersed on the electron-donating groups, and the LUMOs (lowest unoccupied molecular orbitals) are predominantly dispersed on the electron-accepting units, suggesting bipolar charge transporting property. Two yellow phosphorescent organic light-emitting diodes (PHOLEDs, ITO (indium tin oxide)/TAPC (1,1-bis[4-(di-p-tolylamino) phenyl]cyclohexane, 40 nm)/host: Ir(bt)2(acac) (bis(2-phenylbenzothiozolato-N,C2′) iridium(acetylacetonate), 15 wt%, 20 nm)/TmPyPB (1,3,5-tri(m-pyrid-3-yl-phenyl) benzene, 40 nm)/LiF (1 nm)/Al (100 nm)) fabricated using NONP and NONM as the host and Ir(bt)2(acac) as the emitter exhibit maximum current efficiencies (ηc,max) of 43.2 and 44.4 cd A-1, respectively, with low current efficiency roll-off. The values of 40.4 and 43.6 cd A-1can still be achieved at the luminance of 3000 cd m-2, respectively.
- Zhang, Song,Xu, Qiu-Lei,Xia, Jing-Cheng,Jing, Yi-Ming,Zheng, You-Xuan,Zuo, Jing-Lin
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- The preparation, characterization and catalytic activity of Ni NPs supported on porous alginate-g-poly(p-styrene sulfonamide-co-acrylamide)
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Herein, we report the synthesis of nickel nanoparticles under mild conditions using porous alginate-g-poly(p-styrene sulfonamide-co-acrylamide) as a protecting/stabilizing agent and sodium borohydride as a reducing agent. The porous cross-linked polymeric support was preparedviacombining the use of sol-gel, nanocasting, and crosslinking techniques, in which thep-styrene sulfonamide monomer (PSSA) andN,N′-methylene-bis (acrylamide) (MBA) cross-linker underwent copolymerization on the surface of sodium alginate in the presence of a SiO2nanoparticle (NP) template (Alg-PSSA-co-ACA). The prepared catalyst (Alg-PSSA-co-ACA@Ni) showed high catalytic activity for the one-step synthesis of 1,3,4-oxadiazoles from the reaction of hydrazides and aryl iodides through isocyanide insertion/cyclization.
- Alavinia, Sedigheh,Ghorbani-Vaghei, Ramin
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p. 29728 - 29740
(2021/10/06)
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- Spiroconjugated Tetraaminospirenes as Donors in Color-Tunable Charge-Transfer Emitters with Donor-Acceptor Structure
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Charge-transfer emitters are attractive due to their color tunability and potentially high photoluminescence quantum yields (PLQYs). We herein present tetraaminospirenes as donor moieties, which, in combination with a variety of acceptors, furnished 12 charge-transfer emitters with a range of emission colors and PLQYs of up to 99 %. The spatial separation of their frontier molecular orbitals was obtained through careful structural design, and two DA structures were confirmed by X-ray crystallography. A range of photophysical measurements supported by DFT calculations shed light on the optoelectronic properties of this new family of spiro-NN-donor-acceptor dyes.
- Adachi, Chihaya,Adler, Florin,Chan, Chin-Yiu,Esser, Birgit,Grenz, David C.,Hermann, Mathias,Rose, Daniel,W?ssner, Jan S.,Wilbuer, Jennifer
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- Experimental and Theoretical Studies on the Mechanism of DDQ-Mediated Oxidative Cyclization of N-Aroylhydrazones
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The controversial single-electron-transfer process, frequently proposed in many 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)-mediated reactions, was investigated experimentally and theoretically using the oxidative cyclization of aroylhydrazone with DDQ. DDQ-mediated oxadiazole formation involves several processes, including cyclization to form an oxadiazole ring and N-H bond cleavage, either by proton, hydride, or hydrogen atom transfer. The detailed mechanistic study using the M06-2X density functional theory, and the 6-31+G(d,p) basis set, suggests that the pathways involving radical ion pair (RIP) intermediates, which resulted from single-electron transfer (SET), were found to be energetically nearly identical to the pathway without the SET. The substituent-dependent reactivity of oxadiazole formation was consistent with the free energy profiles of both pathways, with or without the SET. This result indicates that in addition to the electron-transfer pathway, the nucleophilic addition/elimination pathway for DDQ should be considered as a possible mechanism of the oxidative transformation reaction using DDQ.
- Baek, Jihye,Je, Eun-Kyung,Kim, Jina,Qi, Ai,Ahn, Kwang-Hyun,Kim, Yongho
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p. 9727 - 9736
(2020/10/02)
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- Electrochemical Synthesis of 2,5-Disubstituted 1,3,4-Oxadiazoles from α-Keto Acids and Acylhydrazines Under Mild Conditions
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1,3,4-Oxadiazoles are a kind of useful heterocycles which can be frequently found in materials and bioactive molecules. In this study, intermolecular electrochemical cyclization between α-keto acids and acylhydrazines has been developed for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles with the yield up to 91 %. This transformation can be run under mild reaction conditions in the absence of external oxidant, base and transition metal catalyst. Both symmetrical and unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles could be prepared according to the careful choice of the substrate combination. Gram scale synthesis also illustrates the potential application of this protocol in large preparation.
- Lu, Fangling,Gong, Fengping,Li, Liangsen,Zhang, Kan,Li, Zhen,Zhang, Xinwei,Yin, Ying,Wang, Ying,Gao, Ziwei,Zhang, Heng,Lei, Aiwen
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supporting information
p. 3257 - 3260
(2020/05/25)
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- Sodium hypochlorite-mediated synthesis of 2,5-disubstituted 1,3,4-oxadiazoles from hydrazides and aldehydes
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[Figure not available: see fulltext.] A simple and convenient method for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles has been developed. Structurally divergent symmetrical and unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles can be obtained in moderate to high yields via NaOCl-mediated oxidative cyclization of N-acylhydrazones, generated in situ from aliphatic and aromatic hydrazides and aldehydes.
- Paidi, Karuna Raman,Kolli, Murali Krishna,Reddy, Eeda Koti,Pedakotla, Venkata Ramana
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p. 371 - 376
(2020/05/04)
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- Oxadiazole- and indolocarbazole-based bipolar materials for green and yellow phosphorescent organic light emitting diodes
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New bipolar materials, namely 2-phenyl-5-(4-(5-phenylindolo [3,2-a]carbazol-12(5H)-yl)phenyl)-1,3,4-oxadiazole (ICz-OXD) and 2,5-bis(4-(5-phenylindolo [3,2-a]carbazol-12(5H)-yl)phenyl)-1,3,4-oxadiazole (2ICz-OXD), were designed and synthesized. Tree different devices were fabricated using ICz-OXD and 2ICz-OXD as host and fluorescent materials: a green phosphorescent, yellow phosphorescent, and non-doped fluorescent OLED emitter. The yellow phosphorescent OLED device based on the 2ICz-OXD host presented good maximum current, power, and external quantum efficiencies, whose values were 47.55 cd/A, 49.80 lm/W, and 21.54%, respectively. Its efficiencies were better than those of the devices based on ICz-OXD and on the reference material 4,4′-Bis(N-carbazolyl)-1,1′-biphenyl (CBP). The green phosphorescent OLED device with ICz-OXD revealed higher efficiencies than the device based on 2ICz-OXD. The current, power, and external quantum efficiencies based on ICz-OXD were 49.79 cd/A, 52.14 lm/W, and 16.50%, respectively. The non-doped fluorescent devices that used our bipolar materials (ICz-OXD, 2ICz-OXD) exhibited blue emission at 435 and 442 nm.
- Wu, Qiong,Braveenth, Ramanaskanda,Bae, Il-Ji,Zhang, Heng-Qiang,Jung, Hasu,Kim, Miyoung,Chai, Kyu Yun
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- UV-Induced 1,3,4-Oxadiazole Formation from 5-Substituted Tetrazoles and Carboxylic Acids in Flow
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A range of 1,3,4-oxadiazoles have been synthesized using a UV-B activated flow approach starting from carboxylic acids and 5-substituted tetrazoles. The application of UV light represents an attractive alternative to the traditional thermolytic approach and has demonstrated comparable efficiency and versatility, with a diverse substrate scope, including the incorporation of highly substituted amino acids.
- Green, Luke,Livingstone, Keith,Bertrand, Sophie,Peace, Simon,Jamieson, Craig
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supporting information
p. 14866 - 14870
(2020/11/11)
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- Photocatalyzed facile synthesis of 2,5-diaryl 1,3,4-oxadiazoles with polyaniline-?g-C3N4-TiO2 composite under visible light
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PANI (polyaniline)-g-C3N4-TiO2 composite was prepared and found to be efficient for the synthesis of 2,5-diaryl 1,3,4-oxadiazoles under visible light. This reaction involved decarboxylation and cyclization from α-keto acids with acylhydrazines, and a broad scope of substrates were tolerated to provide the desired products in moderate to good yields. Control experiments indicated that a radical pathway was involved in the present photocatalytic reaction and a synergistic effect may exist in the ternary composite. Moreover, this semiconductor photocatalyst could be readily recovered and showed good reusability with only slight decrease in the catalytic activity after six consecutive runs.
- Wang, Liang,Wang, Yaoyao,Chen, Qun,He, Mingyang
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supporting information
p. 1489 - 1492
(2018/03/13)
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- Oxadiazole-based highly efficient bipolar fluorescent emitters for organic light-emitting diodes
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In this study, a series of bipolar fluorescence emitters named 2DPAc-OXD, DPAc-OXD, 2PTZ-OXD and PTZ-OXD were designed and synthesized with excellent yields. The characterization of materials was investigated by using nuclear magnetic resonance (NMR) (1H, 13C), mass spectrometry and thermogravimetric analysis (TGA). To investigate device efficiencies, two different OLED devices (Device 1, Device 2) were fabricated with two different host materials (Bepp2, DPEPO). The Device 2 with 2PTZ-OXD as fluorescent emitter exhibited excellent power and current efficiencies of 6.88 Lm/W and 10.10 cd/A, respectively. The external quantum efficiency of 2PTZ-OXD was around 3.99% for Device 2. The overall device properties of phenothiazine donor were better than acridine derivatives.
- Wu, Qiong,Braveenth, Ramanaskanda,Zhang, Heng Qiang,Bae, Il-Ji,Kim, Miyoung,Chai, Kyu Yun
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- Novel electron transporting materials for highly efficient fully solution-processed green PhOLEDs with low rolls-off and drive voltage
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Two novel alcohol-soluble electron transporting materials, diphenyl(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl)phosphine oxide (PhOXDPO) and ((1,3-phenylenebis(1,3,4-oxadiazole-5,2-diyl))bis(4,1-phenylene))bis(diphenylphosphine oxide) (Ph2OXDPO), were synthesized and utilized in fully solution-processed green phosphorescent organic light emitting diodes (PhOLEDs). The photo-physical, electrochemical and thermal properties, and electron mobility of PhOXDPO and Ph2OXDPO had been investigated in detail. The photo-physical and electrochemical result showed that the PhOXDPO and Ph2OXDPO had lower highest occupied molecular orbitals (HOMO) level (?6.24 eV and ?6.09 eV) and high triplet level (2.79 eV and 2.66 eV). Both PhOXDPO and Ph2OXDPO achieved high electron mobility of 6.6 × 10?4 cm2 v?1 s?1 and 6.0 × 10?4 cm2 v?1 s?1. The current efficiency of the device based on PhOXDPO reached 49.5 cd A?1, and showed only 1.5% roll-off at 1000 cd m?2. Due to the more matchable energy gap and low HOMO level of PhOXDPO, the PhOXDPO based device presented better efficiency than the device with Ph2OXDPO as ETL. Compared with the ETL-free device, the efficiencies of the devices based on PhOXDPO and Ph2OXDPO increased up to one order of magnitude, and remained a high level (38.666 cd A?1 and 37.834 cd A?1, at 10000 cd m?2). The device used TPBI as ETL made by vacuum evaporation and the device ultilized Bphen as ETL made by spin-coating showed much lower efficiency and luminance, on every voltage, than the devices based on PhOXDPO and Ph2OXDPO.
- Wu, Cao,Zhong, Zhi-Ming,Li, Xiang-Gao,Xiao, Yin,Peng, Feng,Wang, Xue,Huang, Zhen-Qiang,Wang, Shi-Rong,Ying, Lei
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- One-pot cyclization/decarboxylation of α-keto acids and acylhydrazines for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles under transition-metal-free conditions
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A one-pot KI/TBHP-mediated oxidative cyclization of α-keto acids with acylhydrazines was developed. A series of functional 2,5-disubstituted 1,3,4-oxadiazoles were synthesized through a tandem keto amine condensation followed by oxidative cyclization and decarboxylation reactions. This procedure was achieved under transition-metal-free conditions and showed advantages including readily available materials, mild reaction conditions and good group tolerance.
- Gao, Peng,Wang, Juan,Bai, Zijing,Cheng, Hualei,Xiao, Jian,Lai, Mengnan,Yang, Desuo,Fan, Mingjin
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supporting information
p. 4616 - 4619
(2016/09/23)
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- Synthesis of New Alkynyl-Bridged 2,5-Disubstituted 1,3,4-Oxadiazoles
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A synthesis of new alkynyl-derived 2,5-disubstituted 1,3,4-oxadiazoles through palladium/copper-catalyzed Sonogashira cross-coupling between oxadiazole-substituted phenyl bromides and various arylacetylenes is described. Investigation of the absorption and emission spectra of the target compounds indicates emission profiles in the near-blue and blue region and high luminescence intensities. The presented approach is very convenient for the synthesis of luminescent small-molecules or precursors of other complex derivatives that are useful in the preparation of OLEDs as electron-transporting components.
- Paun, Anca,Paraschivescu, Codruta C.,Matache, Mihaela,Parvulescu, Vasile I.
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p. 606 - 614
(2016/02/14)
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- Palladium-Catalyzed Aminocarbonylation Reaction to Access 1,3,4-Oxadiazoles using Chloroform as the Carbon Monoxide Source
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A palladium-catalyzed aminocarbonylation reaction of aryl halides with chloroform and tetrazoles has been developed, where chloroform was employed as the carbon monoxide (CO) source in the presence of cesium hydroxide. The in situ generated N-acylated tetrazoles were unstable and easily decomposed to afford 2,5-disubstituted 1,3,4-oxadiazoles. A wide range of tetrazoles and aryl halides reacted smoothly under the optimized reaction conditions to give the corresponding products in moderate to good yields.
- Li, Zhengyi,Wang, Liang
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p. 3469 - 3473
(2016/01/25)
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- One-Pot Synthesis of 2,5-Diaryl 1,3,4-Oxadiazoles via Di-tert-butyl Peroxide Promoted N-Acylation of Aryl Tetrazoles with Aldehydes
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A metal- and base-free protocol for one-pot synthesis of 2,5-diaryl 1,3,4-oxadiazoles via a radical-promoted cross-dehydrogenative coupling strategy was developed. This reaction involved the N-acylation of aryl tetrazoles with aryl aldehydes, followed by thermal rearrangement. A wide range of aryl tetrazoles and aryl aldehydes survived the reaction conditions to deliver the corresponding products in moderate to good yields. (Chemical Equation Presented).
- Wang, Liang,Cao, Jing,Chen, Qun,He, Mingyang
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supporting information
p. 4743 - 4748
(2015/05/13)
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- Organocatalytic Oxidative Amidation of Aldehydes with Tetrazoles to Construct 2,5-Diaryl 1,3,4-Oxadiazoles
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A practical and metal-free oxidative amidation of aldehydes with tetrazoles into 1,3,4-oxadiazoles has been developed by employing tetrabutylammonium iodide (TBAI) as catalyst and tert-butyl hydroperoxide (TBHP) as oxidant. A wide range of 2,5-disubstituted 1,3,4-oxadiazoles can be conveniently generated in moderate to good yields. Gram-scale reaction was also realized in this catalytic system..
- Cao, Jing,Wang, Liang
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supporting information
p. 1239 - 1243
(2015/11/27)
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- LIGHT-EMITTING ELEMENT, LIGHT-EMITTING DEVICE, AND ELECTRONIC DEVICE
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The present invention refers to and light emitting element using phosphorescent compounds to suitable provides device structure wherein the. Furthermore, the present invention refers to said by the use of having a high emission efficiency light-emitting device with high. In particular, the present invention refers to emits a long-life light-emitting device with high. Hole transport-magnetic host material and phosphorescent compound including number 1 luminescence layer and an electron-transporting host material and phosphorescent compound emitting layer including number 2, number 1 number 2 a luminescent layer number 1 light emitting layer and in contact with one another between electrode number 2 electrode and a light emitting element is is produced.
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- In situ generated cetyltrimethylammonium bisulphate in choline chloride-urea deep eutectic solvent: A novel catalytic system for one pot synthesis of 1,3,4-oxadiazole
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Cetyltrimethylammonium bisulphate ([CTA]HSO4) catalysed one pot synthesis of 2,5-disubstituted-1,3,4-oxadiazoles from carboxylic acid and acid hydrazide in biodegradable deep eutectic solvent is investigated. [CTA]HSO 4 is generated in situ from cetyltrimethylammonium peroxodisulphate. Cyclization of diacylhydrazide using [CTA]HSO4 gives best alternative to traditional dehydration agents. Its remarkable features include a milder procedure, simplicity in workup and purification, good to excellent yields of products, use of inexpensive, recyclable reagents, and eco-friendly aspects by avoiding toxic catalysts/reagents and solvents. Graphical Abstract: [Figure not available: see fulltext.].
- More, Priyanka Anant,Gadilohar, Balu Laxman,Shankarling, Ganapati Subray
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p. 1393 - 1398
(2014/08/18)
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- C-H arylation of azaheterocycles: A direct ligand-free and Cu-catalyzed approach using diaryliodonium salts
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An efficient and high yielding Cu-catalyzed direct C-H arylation of azaheterocycles including oxadiazoles, thiadiazoles, benzoxazoles and benzothiazoles has been achieved by employing easily accessible diaryliodonium salts. the Partner Organisations 2014.
- Kumar, Dalip,Pilania, Meenakshi,Arun,Pooniya, Savita
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supporting information
p. 6340 - 6344
(2014/08/18)
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- Visible-light-promoted aerobic oxidative cyclization to access 1,3,4-oxadiazoles from aldehydes and acylhydrazides
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A novel and practical access to symmetrical and unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles directly from aldehydes and acylhydrazides using visible light irradiation under an air atmosphere in the presence of eosin Y as an organophotoredox catalyst at rt is reported. This is the first example of oxidative cyclization of acylhydrazones employing air and visible light as inexpensive, readily available, non-toxic, and sustainable reagents.
- Yadav, Arvind K.,Yadav, Lal Dhar S.
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supporting information
p. 2065 - 2069
(2014/04/03)
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- Microwave-assisted one-step synthesis of 2,5-disubstituted-1,3,4- oxadiazoles using 1,4- bis(triphenylphosphonium)-2-butene peroxodisulfate
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A series of 1,3,4-oxadiazoles were efficiently synthesized from the cyclization-oxidation reaction of acyl hydrazones by using 1,4- bis(triphenylphosphonium)-2-butene peroxodisulfate as an oxidant in solvent-free medium under microwave irradiation.
- Gorjizadeh, Maryam,Afshari, Mozhgan,Nazari, Simin
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p. 1627 - 1630
(2014/05/06)
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- One-pot, three component synthesis of 2,5-disubstituted 1,3,4-oxadiazoles catalyzed by heteropolyacid
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H6[PMo9V3O40] was used as an efficient catalyst for the preparation of 1-aroyl-2-arylidene hydrazines. 2,5-Disubstituted 1,3,4-oxadiazoles have been synthesized by oxidation of 1-aroyl-2-arylidene hydrazines with CrO3 in excellent yields.
- Heravi, Majid M.,Zadsirjan, Vahideh,Bakhtiari, Khadijeh,Bamoharram, Fatemeh F.
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p. 259 - 263
(2013/03/29)
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- Efficient oxidative cyclization of N -acylhydrazones for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles using t-BuOI under neutral conditions
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An efficient procedure for the oxidative cyclization of N -acylhydrazones was developed utilizing tert-butyl hypoiodite (t-BuOI), which is generated in situ from t -BuOCl and NaI. A variety of 2,5-disubstituted 1,3,4-oxadiazoles were synthesized in high yields within short reaction time. The method is also suitable for cyclization of N -acylhydrazones derived from heterocyclic aldehydes and aliphatic aldehydes. Mild reaction conditions and simple workup operations make the procedure a good alternative for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles.
- Gao, Peng,Wei, Yunyang
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p. 113 - 119
(2013/05/23)
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- Efficient oxidative cyclisation of acid hydrazides to 2,5-disubstituted 1,3,4-oxadiazoles catalysed by Bu4NI with t-BuOOH as oxidant
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Acid hydrazides or araldehyde N-acylhydrazones can be converted in good yields to, respectively, symmetrical or unsymmetrical, 2,5-disubstituted 1,3,4-oxadiazoles at 60 °C by a Bu4NI-catalysed procedure which requires the presence of a base and 2.5 equiv. of t-butyl hydroperoxide.
- Gao, Peng,Wei, Yunyang
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p. 506 - 510
(2013/09/12)
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- Synthesis, structure, photophysical and electrochemical properties of series of new fac-triscyclometallated iridium complexes with carbazole or oxadiazole moieties
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A series of new fac-triscyclometallated iridium complexes Ir(Ln) 3 (n = 1-6) (L1: 2-{4-[5-phenyl-[1,3,4]oxadiazol-2-yl]- phenyl}-pyridine, L2: 2-{4-[5-(4-tert-butyl-phenyl)-[1,3,4] oxadiazol-2-yl]- phenyl}-pyridine, L3: 9-(4-pyridin-2-yl-phenyl)-9H-carbazole, L4: 1-[4-(5-phenyl-[1,3,4]oxadiazol-2-yl)-phenyl]-isoquinoline, L5: 1-{4-[5-(4-tert-butyl-phenyl)-[1,3,4] oxadiazol-2-yl]-phenyl}-isoquinoline, L6: 9-(4-isoquinolin-1-yl-phenyl)-9H-carbazole) based on Ir(ppy)3 (ppy = phenyl-pyridine) and Ir(piq)3 (piq = 1-phenylisoquinoline) were synthesized from Ir(acac)3 and corresponding ligands by a new and effective way using anthracene as a solvent. Single-crystal X-ray diffraction spectra of three complexes were studied and the iridium centers were found to adopt distorted octahedral coordination geometry. UV-Vis, photoluminescence, cyclic voltammetry were employed for studying the photophysical and electrochemical properties. These complexes exhibit intense phosphorescence in toluene solution at room temperature with high quantum efficiencies (0.07-0.58) and submicrosecond lifetimes (0.57-0.87 μs).
- Xu, Qiu-Lei,Li, Hong-Yan,Wang, Cheng-Cheng,Zhang, Song,Li, Tian-Yi,Jing, Yi-Ming,Zheng, You-Xuan,Huang, Wei,Zuo, Jing-Lin,You, Xiao-Zeng
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- 17O NMR studies of substituted 1,3,4-oxadiazoles
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Three series of substituted 1,3,4-oxadiazoles were studied by 17O NMR spectroscopy. Chemical shifts values were correlated with empirical Hammett parameters as well as calculated bond lengths and chemical shielding values.
- Gierczyk, Blazej,Zalas, MacIej,Kazmierczak, Marcin,Grajewski, Jakub,Pankiewicz, Radoslaw,Wyrzykiewicz, Bozena
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p. 648 - 654
(2012/01/06)
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- Cu(II) catalyzed imine C-H functionalization leading to synthesis of 2,5-substituted 1,3,4-oxadiazoles
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A direct access to symmetrical and unsymmetrical 2,5-disubstituted [1,3,4]-oxadiazoles has been accomplished through an imine C-H functionalization of N-arylidenearoylhydrazide using a catalytic quantity of Cu(OTf)2. This is the first example of amidic oxygen functioning as a nucleophile in a Cu-catalyzed oxidative coupling of an imine C-H bond. These reactions can be performed in air atmosphere and moisture making it exceptionally practical for application in organic synthesis.
- Guin, Srimanta,Ghosh, Tuhin,Rout, Saroj Kumar,Banerjee, Arghya,Patel, Bhisma K.
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p. 5976 - 5979
(2012/01/02)
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- A novel, one-pot synthesis of 2,5-disubstituted-1,3,4-oxadiazoles using 1,4-bis(Triphenylphosphonium)-2-butene peroxodisulfate
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An efficient and convenient synthesis of 1,3,4-oxadiazoles from aromatic aldehydes, acyl hydrazide, and 1,4- bis(triphenylphosphonium)-2-butene peroxodisulfate is reported. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.
- Badri, Rashid,Gorjizadeh, Maryam
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experimental part
p. 544 - 549
(2010/06/12)
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- Ruthenium (II) polypyridyl complexes based on bipyridine and two novel diimine ligands with carrier-transporting unit: Synthesis, photoluminescence and redox properties
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A series of ruthenium (II) complexes, [Ru(bpy)2L]X2 (L = L1, L2; X = Cl-, PF6-, SCN-), were synthesized based on bipyridine and two novel diimine ligands L1 and L2 (L1 = 1-(4-5′-phenyl-1,3,4-oxadiazolylphenyl)-2-pyridinyl-benzoimidazole, L2 = 1-(4-carbazolylphenyl)-2-pyridinylbenzimidazole); and the crystal structure of [Ru(bpy)2L1]Cl2 was also described. [Ru(bpy) 2(Pybm)]X2 (Pybm = 2-(2-pyridine)benzimidazole) complexes were also prepared as reference samples. In the UV-vis absorption spectra there are one strong π → π (*) transition and two dπ (Ru) → π (*) transitions. By comparisons of photoluminescence properties between [Ru(bpy)2L]X (L = L1, L2) and the reference complexes we find that the complexes with carrier-transporting groups of carbazole and oxadizole have the higher emission intensity and quantum efficiency. One reversible oxidation process in the range 0.80-1.00 V exists in each of the complexes which is assigned to the metal oxidation, [Ru(III)(bpy)2L]2+ + e-[Ru(II)(bpy)2L]+. The comparisons of PL and quantum efficiency between the [Ru(bpy)2L]X2 (L = L1 (1-(4-5′-phenyl-1,3,4-oxadiazolylphenyl)-2-pyridinyl-benzoimidazole), L2 (1-(4-carbazolylphenyl)-2-pyridinylbenzimidazole), X = Cl-, PF 6-, SCN-) and [Ru(bpy)2(Pybm)]X 2 (X = Cl-, PF6-, SCN-) suggest these ligands containing carrier-transporting groups are more benefit to the luminescence of the ruthenium (II) complexes than the based starting ligand (Pybm) due to the more rigid structure and more efficient shielding of the Ru (II) core towards external quenching.
- Wu, Jing,Li, Hong-Yan,Kang, Ling-Chen,Li, Dong-Ping,Xu, Qiu-Lei,Zhu, Yu-Cheng,Tao, Yun-Mei,Zheng, You-Xuan,Zuo, Jing-Lin,You, Xiao-Zeng
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experimental part
p. 2048 - 2056
(2010/09/20)
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- Synthesis and photoluminescence properties of four rhenium(I) complexes based on diimine ligands with oxadiazole/carbazole moiety
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By introducing two carrier-transporting moieties (oxadiazole and carbazole) into two diimine ligands (2-(2-pyridine)-benzimidazole and 2,2'-dipyridylamine), respectively, four novel ligands (L1-L4) and their corresponding rhenium(I) complexes (1-4) have been synthesized and characterized by elemental analysis, 1H NMR and IR spectra. Their photophysical properties, thermal analysis, along with the X-ray crystal structure analysis of L4 and corresponding complex 4 are also described. In absorption spectra, the 2-(2-pyridine)-benzimidazole containing complexes 1, 2 show the intraligand charge-transfer (π→π*(L)) bands and metal-to-ligand charge-transfer dπ(Re)→π*MLCT bands, while the 2,2'-dipyridylamine containing complexes 3, 4 only show the π→π*bands. In the excitation spectra, all the complexes show strong MLCT bands. After excitation of π→π*or MLCT bands, all the four Re(I) complexes exhibit broad bands around 550-560nm due to the Re(I)-based 3MLCT emission. The two complexes 1 (with oxadiazole moiety) and 2 (with carbazole moiety) show the photoluminescence quantum efficiency of 2.0% and 7.5% in solid state, respectively, indicating that the carbazole unit is the better chromophore to enhance the luminescence efficiency of diimine Re(I) complexes than the oxadiazole moiety.
- Wu, Jing,Li, Hong-Yan,Kang, Ling-Chen,Li, Dong-Ping,Li, Huan-Rong,Zhou, Xin-Hui,Sui, Yan,Zheng, You-Xuan,Zuo, Jing-Lin,You, Xiao-Zeng
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experimental part
p. 135 - 142
(2010/11/04)
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- A novel and direct synthesis of 1,3,4-oxadiazoles or oxazolines from carboxylic acids using cyanuric chloride/indium
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Direct synthesis of various oxazolines and 1,3,4-oxadiazoles from carboxylic acids was achieved using cyanuric chloride/indium under very mild conditions.
- Kangani, Cyrous O.,Day, Billy W.
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experimental part
p. 5332 - 5335
(2009/12/06)
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- Copper-mediated direct arylation of 1,3,4-oxadiazoles and 1,2,4-triazoles with aryl iodides
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The copper-mediated direct arylation of 1,3,4-oxadiazoles and 1,2,4-triazoles with aryl iodides proceeds efficiently in the presence of suitable ligands and bases. This method allows the installation of a variety of aryl moieties bearing a functional group such as ketone, ester, or nitrile so as to enable the facile construction of various functionalized oxadiazole and triazole core π systems.
- Kawano, Tsuyoshi,Yoshizumi, Tomoki,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information; experimental part
p. 3072 - 3075
(2009/12/06)
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- Convenient preparation of unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles promoted by Dess-Martin reagent
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2,5-Disubstituted 1,3,4-oxadiazoles have been conveniently prepared by oxidative cyclization of N-acyl-N′-aryliden-hydrazines promoted by an excess of Dess-Martin periodinane under mild conditions (23 examples, up to 92% isolated yields).
- Dobrotǎ, Cristian,Paraschivescu, Codru?a C.,Dumitru, Ioana,Matache, Mihaela,Baciu, Ion,Ru?ǎ, Lavinia L.
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scheme or table
p. 1886 - 1888
(2009/07/05)
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- Quinoxaline Derivative and Light-Emitting Element, Light-Emitting Device, and Electronic Device Using Quinoxaline Derivative
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An object is to provide a novel quinoxaline derivative. Another object is to provide a light-emitting element with low driving voltage. Another object is to provide a light-emitting element with low power consumption. Another object is to provide a light-emitting device and an electronic device with low power consumption by using such a light-emitting element. A quinoxaline derivative which has a structure in which at least one of carbon at a 2-position and carbon at a 3-position of quinoxaline, and carbon of 1,3,4-oxadiazole ring are bound via an arylene group is provided.
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Page/Page column 69-68
(2009/06/27)
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- Tetrazoles: LIII. Microwave-activated acylation of 5-substituted tetrazoles
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The acylation of 5-aryl(hetaryl)tetrazoles with acetic and benzoic anhydrides under microwave irradiation gave the corresponding 2-substituted 5-methyl-and 5-phenyl-1,3,4-oxadiazoles in high yields. The use of microwave activation reduces the reaction temperature by 30-40°C and shortens the reaction time by a factor of 5 to 7.
- Efimova,Artamonova,Koldobskii
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experimental part
p. 1345 - 1347
(2009/09/06)
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- Organometallic complex and light emitting element, light emitting device, and electronic device using the organometallic complex
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To provide an organometallic complex by which red-color light emission can be obtained. In addition, to provide an organometallic complex with high light emission efficiency. Further, to provide an organometallic complex by which red-color light emission with high luminous efficiency can be obtained. An organometallic complex having a structure represented by the following general formula (G1) is provided. (In the formula, A represents an aromatic hydrocarbon group having 6 to 25 carbon atoms. Further, Z represents any one of hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. In addition, Ar1 represents an aryl group having 6 to 25 carbon atoms. R1 represents any one of hydrogen, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Further, M is a central metal and represents an element belonging to Group 9 or Group 10.)
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Page/Page column 70; 71
(2010/11/29)
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- Oxadiazole derivative, and light emitting element, light emitting device, and electronic device using the oxadiazole derivative
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An oxadiazole derivative represented by the following general formula (G1) is synthesized and applied to the light emitting element, wherein Am is a substituent represented by a general formula (Am1), (Am2), or (Am3); each of α, β1, and β2 represents an arylene group having 6 to 25 carbon atoms; each of Ar1 to Ar6 represents an aryl group having 6 to 25 carbon atoms; each of R1 to R3 represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms; and R4 represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 25 carbon atoms.
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Page/Page column 65
(2008/06/13)
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- Oxidative cyclization of aromatic aldehyde n-acylhydrazones by bis(trifluoroacetoxy)iodobenzene
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Aromatic aldehyde N-acylhydrazones were oxidized into 2,5-disubstituted 1,3,4-oxadiazoles with bis(trifluoroacetoxy)iodobenzene in CHCl3 or DMSO at room temperature in good to excellent yields. Copyright Taylor & Francis Group, LLC.
- Shang, Zhenhua
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p. 2927 - 2937
(2007/10/03)
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- Microwave assisted syntheses of 2,5-disubstituted 1,3,4-oxadiazoles
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2,5-Di-substituted 1,3,4-oxadiazoles have been synthesized from the oxidation of 1-aroyl-2-arylidene hydrazines with potassium permanganate on the surface of solid mineral support as well as in the mixture of acetone and water under microwave irradiation. 2,5-Disubstituted 1,3,4-oxadiazoles have been synthesized by oxidation of 1-aroyl-2-arylidene hydrazines with potassium permanganate on the surface of a solid mineral support as well as in mixtures of acetone and water under microwave irradiation.
- Rostamizadeh, Shahnaz,Housaini, S.A. Ghasem
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p. 8753 - 8756
(2007/10/03)
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- Polymer electroluminescent device
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A polymer electroluminescent device (1) comprises an electroluminescent layer (7) of a poly(1,4-phenylenevinylene) having aryl-1,4-phenylene units, where the aryl group is a phenyl, naphthyl or biphenylyl group. Using such a poly(1,4-phenylenevinylene) has the effect that the light emitted by the polymer electroluminescent device has no or at least a reduced tendency to change color when driven the device is and/or kept at an elevated ambient temperature of, for example, 70 °C. The poly(1,4-phenylenevinylene)s having aryl-1,4-phenylene units are prepared using aryl-bishalomethylbenzenes as an intermediate compound.
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- Preparation of functionalized polystyrene-block-polyisoprene copolymers and their luminescence properties
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A series of block copolymers functionalized with aromatic 1,3,4-oxadiazole and stilbene derivatives have been synthesized by the palladium catalyzed reaction between polystyrene-block-polyisoprene and different functional units. These polymers exhibited different emission properties in solution and in the solid state. In chloroform solution, they showed relatively narrow and featured emission bands while, in the solid state, the emission band was broadened and showed a significant red shift. These observations were attributed to the formation of aggregates between the luminophores. After some oxadiazole functionalized copolymers were annealed at elevated temperature, such aggregation was enhanced and there were further changes in the emission spectra. For the bifunctional copolymers, such a shift in the emission band was not significant because the presence of two different chemical species in the same block may prevent the same type of luminophores from aggregating together.
- Hou, Sijian,Chan, Wai Kin
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p. 850 - 856
(2007/10/03)
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- Javelin-, hockey stick-, and boomerang-shaped liquid crystals. Structural variations on p-quinquephenyl
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The ramifications of changing molecular geometry in a series of all-aromatic liquid crystals derived from p-quinquephenyl are reported. Substituting heterocyclic rings such as thiophene, oxadiazole, oxazole, or 1,3-phenylene into the p-quinquephenylene core affects molecular shape changes via the substituent's exocyclic bond angle. In general, we found that introducing nonlinearity into molecules depresses the melting transition temperature. The symmetric (boomerang-shaped) molecules, 2,5-bisbiphenyl-4-yl-1,3,4-oxadiazole, 2,5-bisbiphenyl-4-yl-oxazole, and 1,3-bisbiphenyl-4-yl-benzene, melt into isotropic phases showing small monotropic mesophases. By contrast, the asymmetric (hockey stick-shaped) mesogens, 2-terphenyl-4-yl-5-phenyl thiophene and 2-terphenyl-4-yl-5-phenyl-1,3,4-oxadiazole, exhibit more stable enantiotropic liquid crystalline phases. The hockey stick-shaped mesogens exhibit a smectic phase as well as a nematic phase. High-temperature X-ray determination of the smectic layer spacing gives an unambiguous picture of interdigitated, bilayerlike supramolecular architecture in the smectic phase. There are associated changes in the mesogen's electrostatic profile when a heterocycle is introduced into the quinquiphenylene framework (e.g., conjugation is perturbed). Our findings suggest that steric packing considerations dominate the phase preferences (nematic versus smectic phases). However, electronic considerations (conjugation) appear to control the range of mesomorphism in this new family of nonlinear liquid crystals.
- Dingemans, Theo J.,Murthy, N. Sanjeeva,Samulski, Edward T.
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p. 8845 - 8860
(2007/10/03)
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- TETRAZOLES IN THE SYNTHESES OF 1,3,4-OXADIAZOLES
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Various variants of cleavage of tetrazoles to form 1,3,4-oxadiazoles are examined.The mechanisms and synthetic potentialities of these reactions are discussed.
- Koldobskii, G. I.,Ivanova, S. E.
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p. 1512 - 1517
(2007/10/03)
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- TETRAZOLES. XXX. ACYLATION OF 5-SUBSTITUTED TETRAZOLES
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The acylation of 5-substituted tetrazoles with carboxylic acid chlorides and anhydrides gives rise to 2,5-disubstituted 1,3,4-oxadiazoles in high yields.The reaction goes without the addition of organic bases at 100-105 deg C.The acylation of 5-substituted tetrazoles in a two-phase organic solvent-water system in presence of tetrabutylammonium bromide yields N-acyltetrazoles, which are converted into 2,5-disubstituted 1,3,4-oxadiazoles on thermolysis.
- Myznikov, Yu. E.,Koldobskii, G. I.,Ostrovskii, B. A.,Poplavskii, V. S.
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p. 1125 - 1128
(2007/10/02)
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- TETRAZOLES. ACYLATION OF TETRAZOLES UNDER THE CONDITIONS OF PHASE-TRANSFER CATALYSIS
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The acylation of substituted 5-aryltetrazoles with benzoyl chloride in the presence of tetrabutylammonium bromide in the two-phase methylene chloride-water system leads to the formation of isomeric 1-benzoyl- and 2-benzoyl-5-aryltetrazoles.The ratio of the isomers depens on the nature of the substituents in the phenyl ring; electron-withdrawing substituents increase the proportion of the N2 isomer.The respective 2,5-disubstituted 1,3,4-oxadiazoles are formed during thermolysis, irrespective of the position of the benzoyl group in the N-benzoyltetrazoles.
- Osipova, T. F.,Koldobskii, G. I.,Ostrovskii, V. A.
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p. 2248 - 2252
(2007/10/02)
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