Novel blue‐greenish electroluminescent poly(fluorenevinylene‐alt‐dibenzothiophenevinylene)s and their model compounds

Poly(9,9‐dihexylfluorene‐2,7‐vinylene‐alt‐dibenzothiophene‐2,8‐vinylene) (PS) and poly(9,9‐dihexylfluorene‐2,7‐vinylene‐alt‐dibenzothiophene‐5,5‐dioxide‐2,8‐ vinylene) (PSO) as well as corresponding model compounds were synthesized by Heck coupling. Both the polymers and model compounds were readily soluble in common organic solvents such as tetrahydrofuran, dichloromethane, chloroform, and toluene. The polymers showed a decomposition temperature at ～430 °C and a char yield of about 65% at 800 °C in N₂. The glass‐transition temperatures of the polymers were almost identical (75–77 °C) and higher than those of the model compounds (26–45 °C). All samples absorbed around 390 nm, and their optical band gaps were 2.69–2.85 eV. They behaved as blue‐greenish light emitting materials in both solutions and thin films, with photoluminescence emission maxima at 450–483 nm and photoluminescence quantum yields of 0.52–0.72 in solution. Organic light‐emitting diodes with an indium tin oxide/poly(ethylene dioxythiophene):poly(styrene sulfonic acid)/polymer/Mg:Ag/Ag configuration with polymers PS and PSO as emitting layers showed green electroluminescence with maxima at 530 and 540 nm, respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6790–6800, 2006     

Palladacycles in catalysis - a critical survey

The application of palladacycles as catalysts for cross-coupling and similar reactions is reviewed. In the majority of cases palladacycles are likely to serve as a source of highly active but unstable zero-valent palladium species. In this respect the palladacycles resemble the so-called phosphine-free catalysts. The advantages and limitations of palladacycle catalysts are discussed.     

Heck reactions of stilbenoid chromophores with alkoxysilyl-substituted styrenes: Synthesis of monomers for luminescent polymers

Luminescent stilbenoid chromophores with diethoxysilane end groups are prepared via Heck reactions. Diethoxysilane-substituted styrenes are used as vinylic components, thus allowing the combined connection of the chromophore to the silane moiety with an extension of the π-system. Monodisperse oligo(phenylenevinylene)s of different conjugation lengths and bromine or iodine as reactive sites are used as coupling partners. Electrical and optical properties are tuned via the length of the conjugated system, electron withdrawing cyanide and electron donating alkoxy side chains, the latter guarantee high solubility of the final compounds.Dedicated to Prof. Dr. H. Ringsdorf on the occasion of his 75th birthday     

Synthesis, crystal structure and spectroscopic properties of an unsymmetrical compound with carbazole and benzothiadiazole units

An unsymmetrical organic compound with carbazole (Cz) as donor and benzothiadiazole (BTD) as acceptor (D-π-A-π∗-D∗) was designed and synthesized via simple Heck reaction. The unique crystal structure of Cz-BTD-Cz∗ shows a ladder-like packing mode. A two molecule pair stacks parallelly with each other in each packing unit. In each cell, one Cz moiety is connected with BTD by vinylene bond in same plane. However, the other Cz group is connected to BTD by a one-end vinyl bond in almost perpendicular position to the coplanar part of the molecule. The shortest intermolecular plane distance is 3.48 ± 0.1 Å. The photophysical properties of Cz-BTD-Cz∗ in solution and in bulky crystalline powder state were studied. In bulk crystalline powder state, it has a red-shifted emission band peaked at 609 nm relative to that in solution, and the FWHM was reduced to only 58 nm. Electrochemical properties were also investigated.     

离子液体中用Heck反应合成2-取代萘烯丙醇化合物

利用Heck反应, 在离子液体、金属钯或镍、碱和膦配体反应体系中, 由卤代萘与烯丙醇反应, 制得了高收率和高选择性的2-取代萘烯丙醇化合物. 该方法原料便宜易得、操作简单、反应体系可循环使用. 并讨论了醋酸镍替代醋酸钯、不同膦配体、溶剂及碱对反应转化率的影响. 通过核磁共振、红外光谱、质谱和元素分析对产物的结构进行了表征.     

Synthesis and properties of fluorous arenes and triaryl phosphorus compounds with branched fluoroalkyl moieties (“split pony tails”)

Most compounds designed for immobilization in fluorous media feature linear pony tails of the formula (CH₂)_m(CF₂)_n−1CF₃ [(CH₂)_mR_fn]. This paper presents a first-generation approach to compounds with branched or “split” pony tails of the formula (CH₂)_lCH[(CH₂)_mR_fn]₂. Allyl tri(n-butyl)tin is reacted twice with perfluorooctyl iodide (R_f8I; first, photochemical, 78-81%; second, thermal with radical initiator, 71%; 13-18 g scales) to give the secondary alkyl iodide ICH(CH₂R_f8)₂ (3). A subsequent Ni(Cl)₂(PPh₃)₂-catalyzed reaction with allyl tri(n-butyl)tin yields the branched alkene H₂CCHCH₂CH(CH₂R_f8)₂ (74%). A palladium-catalyzed Heck coupling with OP(p-C₆H₄Br)₃ gives the fluorous phosphine oxide OP(p-C₆H₄CHCHCH₂CH(CH₂R_f8)₂)₃ (84%), and Pd/C-catalyzed hydrogenation affords OP(p-C₆H₄(CH₂)₃CH(CH₂R_f8)₂)₃ (>99%). Reduction with SiHCl₃ gives P(p-C₆H₄(CH₂)₃CH(CH₂R_f8)₂)₃, which is protected as the air-stable borane adduct H₃B·P(p-C₆H₄(CH₂)₃CH(CH₂R_f8)₂)₃ (9, 64%). The CF₃C₆F₁₁/toluene partition coefficient of 9 is much higher than that of the analog with p-(CH₂)₃R_f8 groups (96.6:3.4 versus 37.3:62.7). The iodide 3 is unreactive towards PAr₃ at 175-250 °C. However, a CuBr-catalyzed reaction with C₆H₅MgBr gives C₆H₅CH(CH₂R_f8)₂, which also exhibits a high partition coefficient (97.9:2.1).     

Investigation of the behavior of arenediazonium salts with olefins in BmimPF6

The palladium-catalyzed reactions of olefins with arenediazonium salts in ionic liquids were investigated. For methyl acrylate and methyl acrylonitrile, normal Heck cross-coupling products are obtained in good yields. However, highly selective dimerization products are formed in excellent yields for styrenes. The catalyst system can be recycled.     

含噁二唑单元共轭聚合物合成与性质研究

单体 2 ,5 双 (4 溴苯 ) 1,3,4 二唑 (M Ⅰ )与 1,4 二乙烯基 2 ,5 二正丁氧基苯 (M Ⅱ ) ,在钯催化下通过Heck偶合反应合成得到共轭聚合物 ;单体和聚合物进行了1 H NMR ,1 3C NMR、质谱、FT IR、UV、荧光光谱、GPC、元素分析、热分析等测试 ;二唑 (OXD)基团是一种很好的生色团 ,对氧和热特别稳定 ,二唑环的亲电子性能使其特别适合于作为电子传输层 ,聚合物能发射很强的绿色荧光 ,它将是一类潜在的光电高分子材料     

Palladium complexes of phosphinamine ligands in the intramolecular asymmetric Heck reaction

The synthesis of two novel cyclisation substrates for the asymmetric intramolecular Heck reaction is reported. Their cyclisation, in addition to a known substrate for cis-decalin formation, were tested with palladium complexes of BINAP and heterobidentate oxazoline-containing ligands. In general BINAP provides a more active catalyst system for the range of substrates tested although excellent enantioselectivities of up to 85% were obtained with the P,N ligands studied. A trend was noted whereby the t-leucine-derived oxazoline ligands were more reactive and enantioselective than the valine-derived analogues. Similarly, the diphenylphosphinoferrocenyloxazoline ligands were more reactive and selective than the corresponding diphenylphosphinophenyloxazoline ligands.     

Polystyrene-supported recyclable palladacycle catalyst for Heck, Suzuki and Sonogashira reactions

A new type of soluble polystyrene-supported palladium complex as an excellent and recyclable palladacycle catalyst was discovered for carboncarbon bond formation in Heck, Suzuki and Sonogashira reactions. Precipitation and filtration process for recycling the catalyst was also achieved.