Application of density functional theory in the synthesis of electroactive polymers
Application of density functional theory in the synthesis of electroactive polymers
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DOI：
10.1039/ft9959102331
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
James R. Smith;P. Cox;S. A. Campbell;N. Ratcliffe
中科院分区：
文献类型：
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作者：
James R. Smith;P. Cox;S. A. Campbell;N. Ratcliffe
多种共轭有机化合物经过阳极电聚合产生高导电率的聚合物。然而，电氧化并不总是导致电活性材料的形成，因为一些反应会产生绝缘膜或可溶性低聚物。密度泛函理论（DFT）已被用来通过计算单体自由基阳离子的不成对电子π自旋密度分布来预测电聚合反应的结果，以确定所得聚合物中的偶联位置。计算得出的吡咯、噻吩和 (E)-二苯乙烯的 π 自旋密度与实验值非常吻合。 DFT 已用于研究聚[(E)-3-苯乙烯基噻吩] 和聚[(E)-2-苯乙烯基杂环] 的低电导率和氧化还原惰性。发现相应单体自由基阳离子中的烯烃间隔键处存在高正自旋密度，表明聚合物通过双键进行交联。相比之下，具有改进的电导率的电活性聚合物是由一些(Z)-2-α,β-二芳基丙烯腈的电聚合形成的。对于这些单体，DFT 计算显示最高自旋密度的位置位于杂环的 α 位，表明存在电活性所需的 α、α' 连接单体偶联。
A wide range of conjugated organic compounds undergo anodic electropolymerisation to produce polymers of high conductivity. However, electrooxidation does not always result in the formation of electroactive materials, since some reactions produce insulating films or soluble oligomers. Density functional theory (DFT) has been used to predict the outcome of electropolymerisation reactions by calculating the unpaired electron π-spin density distribution of monomeric radical cations, in order to determine coupling positions in the resultant polymers. π-Spin densities calculated for pyrrole, thiophene and (E)-stilbene are found to be in good agreement with experimental values. DFT has been used to investigate the low conductivity and redox inactivity of poly[(E)-3-styrylthiophenes] and poly[(E)-2-styrylheterocycles]. High positive spin densities at the alkene spacer linkage in the corresponding monomeric radical cations were found, suggesting crosslinking of the polymers via the double bond. In contrast, electroactive polymers of improved conductivity are formed from the electropolymerisation of some (Z)-2-α,β-diarylacrylonitriles. For these monomers, DFT calculations show the positions of highest spin density to be located at the α-positions of the heterocyclic rings, suggesting the presence of α, α′-linked monomeric couplings necessary for electroactivity.