【摘要】 5-溴-2-三甲硅基-二噻吩并[2,3-b:2’,3’-d]噻吩(bt-DTT-Br)与双(三环己基)膦钯(0)进行氧化加成反应,合成了相应的芳基钯(Ⅱ)配合物,X光晶体结构分析表明,配合物中心金属离子为平面四方构型,膦配体处于反式位置。该配合物在加热时可以引发AB型芴单体聚合,得到一个端基为bt-DTT的聚芴共轭聚合物。相似端基结构的聚芴可以由bt-DTT-Br与不同膦配体钯(0)配合物原位生成的芳基钯配合物引发AB型芴单体聚合制备。辅助配体为三(邻甲基苯基)膦或三叔丁基膦时,配合物引发的AB型芴单体聚合室温下即可进行,并给出单一且端基结构明确的聚芴。基质辅助激光解吸电离飞行时间质谱(MALDI-TOF)分析证实,聚合物的一个端基是来自芳基钯配合物中的bt-DTT,另一端基为Br/H原子或封端基团。凝胶渗透色谱(GPC)分析表明,聚合物相对分子质量随单体与催化剂的投料比增加呈线性增长,聚合反应遵循催化剂转移聚合机理。更多还原

【Abstract】 Aryl palladium complex( bt-DTT) Pd( PCy3)2Br was synthesized by oxidative addition of 5-bromo-2-trimethylsilanyl-dithieno[2,3-b: 2’,3’-d]thiophene( bt-DTT-Br) to bis( tericlohexylphosphine) palladium( Pd( PCy3)2). X-ray crystal structure analysis reveals that the complex adopts a nearly square-planar geometry around central Pd atom with the expected trans configuration of the phosphine ligands. The complex can initiate the polymerization of AB-type fluorene monomer under heating conditions to afford the polyfluorene with the defined end group of aryl group bt-DTT derived from the complex( bt-DTT) Pd( PCy3)2Br. The similar conjugated polymers can also be prepared by employing the aryl palladium complexes in situ generated from btDTT-Br/Pd( 0)-species as initiators. Polymerization of AB-type fluorene monomers is achieved at room temperature to give the single polyfluorene with the well-defined end groups while initiators are the complexes with the ancillary ligand of tris( 2-methylphenyl) phosphine( P( o-tol)3) or tri-tert-butylphosphine( P( t-Bu)3). Matrix-assisted laser desorption ionization time-of-flight( MALDI-TOF) mass spectra confirm that the polymers bear a bt-DTT group at one end and a Br/H atom or end-capping group at the other end. Gel permeation chromatography( GPC) analyses demonstrate that molecular mass of polymers increases linearly with increase of the molar ratio of monomer to catalyst,indicating that the polymerizations proceed through the catalyst-transfer mechanism.更多还原