Polythiophenes containing in-chain cobaltabisdicarbollide centers.
Polythiophenes containing in-chain cobaltabisdicarbollide centers.
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DOI：
10.1021/am9007424
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发表时间：
2010-03
影响因子：
9.5
通讯作者：
Vicente, M. Graca H.
中科院分区：
文献类型：
--
作者：
Fabre, Bruno;Hao, Erhong;LeJeune, Zorabel M.;Amuhaya, Edith K.;Barriere, Frederic;Garno, Jayne C.;Vicente, M. Graca H.
合成了新型的共价键连接到两个2-寡聚噻吩单元上的钴（III）双（二卡宾）配合物，并在乙腈电解液中进行了电聚合，制备了相应的含链内金属中心的聚噻吩膜。由联噻吩（4 b）和三噻吩（4c）衍生物电生成的聚合物膜显示归因于Co（III）/Co（II）电对的氧化还原过程。−1.1 V vs SCE，并在约1.5 V时对预期的四噻吩基和六噻吩基链段进行p掺杂/去掺杂。0.8 V vs SCE。相反，噻吩基（4a）衍生物的阳极氧化导致电极表面的钝化。随着低聚噻吩取代基长度的增加，HOMO中的金属和二卡宾笼碳原子的贡献急剧减少，使得4 b和4c的最高占据前线轨道可以被认为是几乎纯粹的低聚噻吩基。进一步的紫外-可见光谱分析表明，引入六噻吩基链段的聚合物比引入四噻吩基链段的聚合物具有更高的共轭性，聚（4 b）和聚（4c）的带间π-π* 跃迁的最大吸收波长分别为410和448 nm。此外，这些聚合物显示出比母体低聚噻吩更大的共轭度。这样的功能表明一个显着的电子离域通过cobaltabisdicarbolide部分。它们的导电探针原子力显微镜表征表明，聚（4 b）和聚（4c）的行为像重掺杂半导体，而不是纯半导体。从电流-电压曲线中提取的聚（4 b）和聚（4c）的平均电导率值分别为1.4 ×10−4和7.5 ×10−4 S cm−1。发现这样的材料对于质子到二氢的电催化还原是有效的，如聚（4 b）所例示的。氢析出的过电位显着降低ca。230 mV（在20 mM HBF 4存在下，在1.4 mA cm-2的电流密度下测量）。
New cobalt(III) bis(dicarbollide) complexes covalently linked to two 2-oligothienyl units have been synthesized and electropolymerized in acetonitrile electrolyte in order to produce the corresponding polythiophene films containing in-chain metallic centers. The polymer films electrogenerated from the bithienyl (4b) and terthienyl (4c) derivatives display redox processes attributed to the Co(III)/Co(II) couple at ca. −1.1 V vs SCE and to the p-doping/undoping of the expected quaterthienyl and sexithienyl segments at ca. 0.8 V vs SCE. In contrast, the anodic oxidation of the thienyl (4a) derivative leads to passivation of the electrode surface. As the length of the oligothiophene substituents increases, the metallic and dicarbollide cage carbon atoms contributions in the HOMO decrease dramatically so that the highest occupied frontier orbitals of 4b and 4c can be considered as almost purely oligothiophene-based. From further UV–vis spectroscopy analysis, it is demonstrated that the polymer incorporating the sexithienyl segments is more conjugated than that with the quaterthienyl segments as the absorption maximum for the interband π–π* transition was observed at 410 and 448 nm for poly(4b) and poly(4c) respectively. Furthermore, these polymers display a more extended degree of conjugation than the parent oligothiophenes. Such features indicate a significant electronic delocalization through the cobaltabisdicarbollide moiety. Their conducting probe atomic force microscopy characterization indicates that poly(4b) and poly(4c) behave like heavily doped semiconductors rather than pure semiconductors. Mean conductivity values extracted from the current–voltage profiles are 1.4 ×10−4 and 7.5 ×10−4 S cm−1 for poly(4b) and poly(4c), respectively. Such materials are found to be efficient for the electrocatalytic reduction of protons to dihydrogen, as exemplified for poly(4b). The overpotential for hydrogen evolution is significantly decreased by ca. 230 mV with respect to that obtained with the bare electrode (measured for a current density of 1.4 mA cm−2 in the presence of 20 mM HBF4).
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影响因子：
1.8
作者：
Hawthorne, M. Frederick;Ramachandran, Bhaskar M.;Knobler, Carolyn B.
通讯作者：
Knobler, Carolyn B.
影响因子：
4.4
作者：
BECKE, AD
通讯作者：
BECKE, AD
影响因子：
8.6
作者：
Hao, Erhong;Fabre, Bruno;Vicente, M. Graca H.
通讯作者：
Vicente, M. Graca H.
影响因子：
5.5
作者：
Barriere, Frederic;Fabre, Bruno;Vicente, M. Graca H.
通讯作者：
Vicente, M. Graca H.
影响因子：
2.6
作者：
Fox, MA;Gill, WR;Colquhoun, HM
通讯作者：
Colquhoun, HM