Synthesis of Polythiophene Derivative bearing Methoxy and Pyridine Groups at the beta-Position and Formation of an Intramolecular Hydrogen Bonding through the Polymer Reaction
Synthesis of Polythiophene Derivative bearing Methoxy and Pyridine Groups at the beta-Position and Formation of an Intramolecular Hydrogen Bonding through the Polymer Reaction
复制标题
β位带有甲氧基和吡啶基团的聚噻吩衍生物的合成以及通过聚合物反应形成分子内氢键
DOI：
10.1016/j.polymer.2017.03.005
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发表时间：
2017
期刊：
影响因子：
4.6
通讯作者：
and Junpei Kawai
中科院分区：
文献类型：
--
作者：
Koji Takagi;Ryo Kochi;and Junpei Kawai
合成了两种3位上带有甲氧基的4-吡啶基噻吩单体M1（2，5-二溴衍生物）和M2（5-溴-2-碘衍生物）。M1 usingi-PrMgCl·LiCl的Grignard复分解反应具有最高的单体转化率（87%）和区域选择性（GM 1/GM 1 ′= 76/24）。随后通过Ni（dppe）Cl 2进行Kumada偶联聚合，得到数均分子量为3000 - 4600的P1-OMe。同样地，从M2获得P2-OMe。根据~ 1H-NMR谱，推测了P_1-OMe和P_2-OMe的区域无规结构。然后使用P1-OMe通过用BBr 3处理进行从甲氧基到羟基酮的转化，得到P1-OH。通过测量聚合物在二氯甲烷中的紫外-可见吸收光谱和薄膜沿着进行的密度泛函理论计算，发现1）吡啶和羟基之间形成分子内氢键导致最大吸收从476 nm（P1-OMe）显著红移到662 nm（P1-OH）; 2）P1-OH具有较少的平面构象，导致在固态下聚合物链的无效π-π堆积。质子掺杂实验和循环伏安测量揭示了P1-OH的氢键特征。
Two 4-pyridylthiophene monomersM1(2,5-dibromo derivative) andM2(5-bromo-2-iodo derivative) having the methoxy group at the 3-position were synthesized. The Grignard metathesis reaction ofM1usingi-PrMgCl·LiCl demonstrated the highest monomer conversion (87%) and regioselectivity (GM1/GM1′= 76/24). The following Kumada coupling polymerization by Ni(dppe)Cl2gaveP1-OMewith the number-averaged molecular weight ranging from 3000 to 4600. Likewise,P2-OMewas obtained fromM2. On the basis of1H-NMR spectra, the regiorandom structure ofP1-OMeandP2-OMewere suggested. The transformation from the methoxy group to the hydroxy one was then carried out usingP1-OMeby treating with BBr3to affordP1-OH. By measuring the UV-vis absorption spectra of polymers in CHCl3and film along with the DFT calculation of model compounds, it was found that 1) the formation of an intramolecular hydrogen bonding between the pyridine and hydroxy groups brings about the significant red-shift of the absorption maxima from 476 nm (P1-OMe) to 662 nm (P1-OH) and 2)P1-OHhas the less planar conformation resulting in the ineffective π-π stacking of polymer chains in the solid state. The proton doping experiments and CV measurements revealed the hydrogen bonding characteristic inP1-OH.