The addition of substituents at the 6,13-position improved the solubility and stability of pentacene, making it possible to use the derivatives in spin coating of organic field-effect transistors(OFETs). Three pentacene derivatives, 6,13-bis(m-tolyl)pentacene(MP), 6,13-bis(4-butylphenyl)pentacene(BP), and 6,13-bis((4-butylphenyl)ethynyl)pentacene(BPEP) were synthesized, and their properties were investigated. 6,13-Pentacenequinone and organolithium were used in the preparation of 6,13-dihydropentacene at 0 ℃, and pentacene derivatives were synthesized with SnCl_2/HCl as reducing agent, to reduce 6,13-dihydropentacene at room temperature. The structure of the derivatives was characterized using NMR. The thermal stability, photochemical properties, and electronic structure of the three compounds were investigated using TGA, cyclic voltammetry, and UV–Vis. BPEP was also characterized using X-ray diffraction and atom force microscopy. BPEP was used to fabricate an OFET device using spin coating. The device showed a mobility of 0.07 cm^2 V s^(-1) at V_(th) =-10 V and I_(ON)/I _(OFF) = 10~2.
The crystal structure of the title compound, diethyl 4,5-di（thienyl）-3,6-bis（trime- thylsilyl）phthalate （C26H3404S2Si2, Mr = 530.83）, has been determined by single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group Pccn with a = 43.008（5）, b = 10.9000（12）, c = 11.9357（14） A, V= 5595.3（11） A3, Z = 8, F（000） = 2256, Dc= 1.260 mg/m3, p = 0.305 mm-1, T = 113（2） K, S = 1.090, R = 0.0413 and wR = 0.0969 for 5952 observed reflections with 1 〉 2o（/）. The benzene ring system is planar and makes dihedral angles of 63.7（2） and 72.5（4） with the two thienyl rings A （C（23）-C（26）, S（2）） and B （C（19）-C（22）, S（1））, respectively. The UV-vis absorption and fluorescence of the title compound were discussed. The molecular structure of the title compound has been optimized using DFT method at the B3LYP/6-31G（d） level. The computational results showed that the optimized geometer parameters are consistent well with the experiment data. The vertical ionization potential, vertical electron affinity and frontier orbitals were also discussed.
Based on the formation of 2,5-bis（trimethylsilyl）-zirconacyclopentadienes from two silylalkynes with CpEZrBu2 and the Cu-mediated formation of 1,4-disilylbenzene via the cycloaddition of zirconacyclopentadienes to disubstituted alkynes, a selective synthesis of 1,4-dialkyl（aryl）-hexa-substituted benzenes was achieved followed by iodination and coupling reaction. The coupling reactions were carried out with either organolithium reagent or orga- nozinc reagent（Negishi coupling）, depending on the electrophilic species.
LI JunqiuZHANG JiqianQU HongmeiLIU JunLI JuanZHOU Lishan
In this study, a new zirconium-mediated cycloaddition for preparing dibenzosilole derivatives was developed using siliconbridged diynes and electron-withdrawing alkynes as starting materials. The preparation of silicon-bridged diynes from 1-bromide-2-iodobenzene, terminal alkynes, and dimethyldichlorosilane was also studied. Unlike in the previous synthesis methods, much higher yields of electron-withdrawing group-substituted dibenzosilole derivatives were obtained. In addition, a new synthesis strategy for preparing benzonaphthosilole derivatives using internal alkynes, 1,4-dibromobenzene, and electron-withdrawing alkynes as starting materials is proposed. Compared with previous methods, alkyl, phenyl, and electron-withdrawing groups can be successfully introduced onto aromatic rings, and the positions of these substituents can be easily controlled. The cycloaddition reactions for dibenzosilole and benzonaphthosilole derivatives are highly efficient one-pot processes, and the raw materials are available and easily prepared. Using these new methods, a series of novel multisubstituted dibenzonsilole and benzonaphthosilole derivatives were obtained effectively.
Hongmei QuXin ZhangXu ChenHui ZhangYican MenJunqiu Li
The linear trienes were obtained in high yields by copper-mediated cycloaddition of 2,5-bis（trimethylsilyl）zirconacyclo- pentadienes with dimethyl acetylenedicarboxylate （DMAD） which can be quantitatively converted to novel asymmetric hex- asubstituted cyclohexadienes with high （E）-stereoselectivity. The structure of cyclohexadienes was determined via X-ray analysis.
Hong Mei QuXin Hui NiuJuan LiJun LiuLi Li JiangJian Ke TangLi Shan Zhou
A series of quinoline derivatives was obtained in high yields by an efficient one-pot reaction of substituted o-diiodobenzenes with azazirconacyelopentadienes, which were conveniently prepared from one internal alkyne and one nitrile mediated by zirconocene. This proposed synthetic method provides a feasible way to the synthesis of large N-heteroeyclic π-conjugated molecules.
MEN YicanZHANG JiqianZHOU LishanLI JunqiuLIU JunLI JuanQU Hongmei
