A carbazole–oxadiazole diad molecule for single-emitting-component white organic light-emitting devices (WOLEDs)

The synthesis is reported of a new molecule consisting of N-phenylcarbazole linked through a butadiyne bridge to 2,5-diphenyl-1,3,4-oxadiazole. The compound shows blue photoluminescence with positive solvatochromism: e.g., λ_max 401 nm in cyclohexane, 461 nm in chloroform solution (quantum yield Φ_f 0.55) and 428 nm in thin film, with a low intensity band extending to ca. 700 nm in films. OLEDs with a device configuration of [ITO/PEDOT:PSS (50 nm)/molecule:PVK:OXD-7 (80 nm)/Bphen (20 nm)/LiF (0.8 nm)/Al (120 nm)] were fabricated. Pure white-light emission with Commission Internationale De L'Eclairage (CIE) coordinates of (0.313, 0.330) at 13 V and good colour stability with a very small offset of coordinates (0.034, 0.033) under biases of 9–15 V has been achieved.     

Synthesis and electroluminescent properties of new diazocine derivatives

ABSTRACT

DAPCz and DANaPCz have been successfully synthesized and characterized. DAPCz and DANaPCz in film state showed absorption in the range of 322 to 345 nm wavelength and exhibited blue photoluminescence (PL) emission peaks at 428 and 425 nm. PL wavelength of DAPCz is red-shifted by 3 nm than that of DANaPCz, which is due to the carbazole electron donating group of DAPCz. The use of DAPCz in a non-doped OLED device resulted in blue emission with current efficiency of 1.01 cd/A and C.I.E. of (0.26, 0.37).     

咔唑-苯并噻唑类衍生物薄膜的线性及非线性光学性质

以咔唑为电子供体,苯并噻唑为电子受体,合成了两种新型咔唑-苯并噻唑衍生物3-(2-苯并噻唑-2-基乙烯基)-N-乙基咔唑和3,6-二(2-苯并噻唑-2-基乙烯基)-N-乙基咔唑,通过核磁共振和分光光度计对其结构进行表征.利用刮刀法制备质量分数为4％的衍生物/聚酰亚胺的复合薄膜.采用透射光谱法和单光束Z-扫描技术分别测试了衍生物的线性和三阶非线性光学特性.Z扫描实验结果表明3-(2-苯并噻唑-2-基乙烯基)-N-乙基咔唑薄膜的非线性吸收系数和非线性折射系数分别为β1=-2.118 9×10-10 cm/W、r1=2.285 2×10-14 cm2/W,具有反饱和吸收特性和自聚焦效应;同时3,6-二(2-苯并噻唑-2-基乙烯基)-N-乙基咔唑薄膜的非线性吸收系数与非线性折射系数分别为β2=-1.275 6×10-9 cm/W、r2=-7.039 9×10-14 cm2/W,具有反饱和吸收特性和自散焦效应.     

Synthesis and characterization of novel conjugated bisindenocarbazoles

We present the synthesis of five new bisindenocarbazoles with different alkyl substituents. The synthesis starts from 2,7-dibromocarbazole and leads to the bisindenocarbazoles 6-10 in five steps with an overall yield of about 50%. By substitution of the core with different alkyl chains in the last step of the synthesis, the morphology of the bisindenocarbazoles can be varied from crystalline materials to molecular glasses. The bisindenocarbazoles are electrochemically stable and exhibit a strong, saturated blue emission with a quantum yield of 63% in solution.     

Enantioselective synthesis of butadien-2-ylcarbinols via (silylmethyl)allenic alcohols from chromium-catalyzed additions to aldehydes utilizing chiral carbazole ligands

The synthesis of chiral, nonracemic butadienylcarbinols by employing intermediate (trimethylsilyl)methylallenic alcohols is described. Allenic alcohols are obtained by treatment of aldehydes with (4-bromobut-2-ynyl)trimethylsilane in the presence of a catalytic amount of CrCl₃ or CrCl₂. Several new tridentate bis(oxazolinyl)carbazole ligands were synthesized and evaluated as the source of chirality. The synthesis of chiral allenic alcohols can be achieved in good yields (58-88%) and enantioselectivities (55-78% ee). Allenic alcohols may be treated with TBAF or 2 M HCl to provide the desired dienes in 43-86% yields. Alternatively, the (trimethylsilyl)methyl allenic alcohols afford iodobutadienyl carbinols when treated with N-iodosuccinimide.     

RAFT聚合制备结构明确的荧光标识聚甲基丙烯酸甲酯

以铁氰化钾为氧化剂,通过N-咔唑二硫代甲酸钠的水相氧化制备了高纯度的中间体二硫化双(N-咔唑硫代甲酰)(DTCD),DTCD以晶体的形式从水中析出,提纯简单,性质稳定.通过DTCD与偶氮二异丁腈(AIBN)或偶氮二氰基戊酸(ACVA)的反应合成了2种性能优异的叔丁腈酯基RAFT试剂,N-咔唑二硫代甲酸异丁腈酯(CYCBD)和N-咔唑二硫代甲酸氰基戊酸(CVCBD),新合成工艺的副反应和杂质被大量减少,最终产物的收率可达80%以上.以CYCBD和CVCBD为可逆加成断裂链转移(RAFT)试剂,研究了它们对甲基丙烯酸甲酯(MMA)RAFT聚合的控制能力,结果表明CYCBD和CVCBD是性能优异的RAFT试剂,可以很好地用于制备结构明确、分子量分布窄的链末端咔唑标记的聚甲基丙烯酸甲酯(CPMMA),由它们所制得的CPMMA的PDI小于1.2.研究结果还表明CYCBD和CVCBD及由其合成的CPMMA在四氢呋喃(THF)溶液中具有显著的荧光特性,CPMMA在358nm处有很强的荧光发射峰,而且,在浓度范围为0.1～20μmol/L的THF溶液中,CPMMA的荧光发射强度与其浓度具有良好的线性关系.通过CYCBD和CVCBD可以方便地制备结构明确且具荧光标识的功能聚合物。     

Palladium-catalyzed phosphination and amination through CH bond functionalization on biphenyl: Amido-substituent as directing group

The formation of N-(2'-(diphenylphosphoryl)-[1,1′-biphenyl]-2-yl)-2,3,4,5,6-pentafluorobenzamide (3_eaaa) has been achieved through the palladium-catalyzed and Ag(I)-assisted CH functionalization of N-([1,1′-biphenyl]-2-yl)-2,3,4,5,6-pentafluorobenzamide (1_eaa) via phosphination and in the presence of diphenylphosphine oxide (2_a). The reaction was accompanied with small amount of carbazole derivative, (9H-carbazol-9-yl)(perfluorophenyl)methanone (4_eaa). Crystal structures of 3_eaaa and 4_eaa were both determined by X-ray crystal diffraction methods. Indeed, phosphination took place at the ortho-position of inter-annular ring of 1_eaa. Substituents with various electron-withdrawing/donating capacities on the amido-fragment of 1 were found to greatly affect the ratio distribution of products 3 and 4. By contrast, substituents on various locations of the biphenyl in 1 do not influence much on the outcome of the products distribution. A reaction mechanism is proposed to account for these experimental observations. Computational studies employing Density Functional Theory methods (DFT) on this proposed mechanism found that the electron density property of the palladium metal center in the intermediate II is critical to the formation of either 3 or 4. A relatively electron-poor palladium metal center favors the pathway of forming 3. On the contrary, the pathway of producing 4 will be prevailed while the palladium metal center is having fair amount of electron-density in the proposed intermediate II.     

Synthesis and characterization of novel N-carbazole end-capped oligothiophene-fluorenes

A series of novel N-carbazole end-capped oligothiophene-fluorenes was synthesized using Ullmann coupling, bromination, and Suzuki coupling reactions. The optical, thermal, and electrochemical properties of these materials can be tuned by varying the conjugation length of the oligothiophene segment. The terminal carbazole and central fluorene moieties of the resulting materials are beneficial for their morphology, conjugation length, and solubility.     

Spectroscopic Characterization of Carbazole-TCAQ Charge-Transfer Salt

Spectroscopic characterizations of carbazole-TCAQ salt were investigated by means of UV-visible and fluorescence spectra. The results show that carbazole and TCAQ can form a kind of charge-transfer salt whose characteristic adsorption is π→π^* of 248 nm when the mixture of the two compounds is irradiated by UV-light, and the charge-transfer salt becomes more stable with the increase of irradiation time.