Heck coupling of olefins to mixed methyl/thienyl monolayers on Si(111) surfaces.
Heck coupling of olefins to mixed methyl/thienyl monolayers on Si(111) surfaces.
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烯烃与 Si(111) 表面上的混合甲基/噻吩单分子层的 Heck 耦合。
DOI：
10.1021/ja402495e
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发表时间：
2013
影响因子：
15
通讯作者：
N. Lewis
中科院分区：
文献类型：
--
作者：
Leslie E. O'Leary;Michael J. Rose;Tina X. Ding;E. Johansson;B. Brunschwig;N. Lewis
用Heck反应将烯烃偶联到由甲基和噻吩基组成的混合单层结构的Si（111）表面。耦合方法在表面和烯烃表面官能团之间保持了共轭连接，从而允许从硅表面轻松转移电荷。仅以噻基结尾的Si（111）表面的表面复合速度S为670±190 cm S(-1)，而覆盖率为θSC4H3 = 0.15±0.02的混合CH3/SC4H3-Si（111）表面的表面复合速度S为27±9 cm S（-1）。因此，用n -溴代琥珀酰亚胺对CH3/SC4H3-Si（111）表面进行溴化处理，得到了覆盖率为θBr-Si < 0.05的混合CH3/SC4H2Br-Si（111）表面。以[Pd(PPh3)4]为催化剂活化了芳基卤化物表面。激活后，Pd（II）通过氧化加成选择性地与表面结合的芳基卤化物配合。然后将烯基底物4-氟苯乙烯、乙烯基二茂铁和原卟啉IX二甲酯偶联（在100°C的二甲基甲酰胺中）到含pd的功能化Si表面。然后用Co、Cu或Zn金属化卟啉修饰的表面。在循环伏安法中，乙烯基二茂铁修饰的Si（111）表面显示出峰值电流与扫描速率的线性关系，表明保持了容易的电子转移，并提供了Si表面与系留二茂铁之间牢固联系的证据。最终的heck偶联表面显示S = 70 cm S(-1)，表明这种将小分子拴在硅光电极上的多步骤合成方法可以产生高质量的表面。
The Heck reaction has been used to couple olefins to a Si(111) surface that was functionalized with a mixed monolayer comprised of methyl and thienyl groups. The coupling method maintained a conjugated linkage between the surface and the olefinic surface functionality, to allow for facile charge transfer from the silicon surface. While a Si(111) surface terminated only with thienyl groups displayed a surface recombination velocity, S, of 670 ± 190 cm s(-1), the mixed CH3/SC4H3-Si(111) surfaces with a coverage of θSC4H3 = 0.15 ± 0.02 displayed a substantially lower value of S = 27 ± 9 cm s(-1). Accordingly, CH3/SC4H3-Si(111) surfaces were brominated with N-bromosuccinimide, to produce mixed CH3/SC4H2Br-Si(111) surfaces with coverages of θBr-Si < 0.05. The resulting aryl halide surfaces were activated using [Pd(PPh3)4] as a catalyst. After activation, Pd(II) was selectively coordinated by oxidative addition to the surface-bound aryl halide. The olefinic substrates 4-fluorostyrene, vinylferrocene, and protoporphyrin IX dimethyl ester were then coupled (in dimethylformamide at 100 °C) to the Pd-containing functionalized Si surfaces. The porphyrin-modified surface was then metalated with Co, Cu, or Zn. The vinylferrocene-modified Si(111) surface showed a linear dependence of the peak current on scan rate in cyclic voltammetry, indicating that facile electron transfer had been maintained and providing evidence of a robust linkage between the Si surface and the tethered ferrocene. The final Heck-coupled surface exhibited S = 70 cm s(-1), indicating that high-quality surfaces could be produced by this multistep synthetic approach for tethering small molecules to silicon photoelectrodes.
影响因子：
56.9
作者：
Lin, VSY;Motesharei, K;Ghadiri, MR
通讯作者：
Ghadiri, MR
影响因子：
5.2
作者：
Stewart, Ian C.;Douglas, Christopher J.;Grubbs, Robert H.
通讯作者：
Grubbs, Robert H.
影响因子：
15
作者：
Stewart, Ian C.;Keitz, Benjamin K.;Kuhn, Kevin M.;Thomas, Renee M.;Grubbs, Robert H.
通讯作者：
Grubbs, Robert H.