- Novel organic semiconductors based on phenyl and phenylthienyl derivatives for organic thin-film transistors
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New phenyl and phenylthienyl derivatives end-functionalized with carbazole and α-carboline, 9-(4- (9H-carbazol-9-yl)phenyl)-9H-carbazole, 9-(4-(9H-carbazol-9-yl)phenyl)-9H-pyrido[2,3-b]indole, 9- (3-(9H-carbazol-9-yl)phenyl)-9H-carbazole, 9-(3-(9H-carbazol-9-yl)phenyl)-9H-pyrido[2,3-b]indole, 9-(4-(5-(9H-carbazol-9-yl)thiophen-2-yl)phenyl)-9H-carbazole, and 9-(3-(5-(9H-carbazol-9-yl) thiophen-2-yl)phenyl)-9H-carbazole were synthesized and characterized as organic semiconductors for organic thin-film transistors (OTFTs). Most compounds exhibited p-channel characteristics with carrier mobility as high as 1.7 × 10-5 cm2/Vs and a current on/off ratio of 102-104 for top-contact/bottom-gate OTFT devices.
- Lee, Eunsoo,Thirupathaiah, Bodakuntla,Han, Jaeuk,Jung, Dahae,Kwon, Guhyun,Kim, Choongik,Seo, Sung Yong
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- Gold-catalyzed oxidative coupling of arylsilanes and arenes: Origin of selectivity and improved precatalyst
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The mechanism of gold-catalyzed coupling of arenes with aryltrimethylsilanes has been investigated, employing an improved precatalyst (thtAuBr3) to facilitate kinetic analysis. In combination with linear free-energy relationships, kinetic isotope effects, and stoichiometric experiments, the data support a mechanism involving an Au(I)/Au(III) redox cycle in which sequential electrophilic aromatic substitution of the arylsilane and the arene by Au(III) precedes product-forming reductive elimination and subsequent cycle-closing reoxidation of the metal. Despite the fundamental mechanistic similarities between the two auration events, high selectivity is observed for heterocoupling (C-Si then C-H auration) over homocoupling of either the arylsilane or the arene (C-Si then C-Si, or C-H then C-H auration); this chemoselectivity originates from differences in the product-determining elementary steps of each electrophilic substitution. The turnover-limiting step of the reaction involves associative substitution en route to an arene π-complex. The ramifications of this insight for implementation of the methodology are discussed.
- Ball, Liam T.,Lloyd-Jones, Guy C.,Russell, Christopher A.
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supporting information
p. 254 - 264
(2014/01/23)
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- Site-selective mono-oxidative addition of active zinc into carbon-bromine bond of dibrominated-thiophenes: Preparation of thienylzinc reagents and their applications
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A facile protocol for the preparation of 3-bromo-2-thienylzinc bromide A and 5-bromo-2-thienylzinc bromide B has been developed. It has been successfully accomplished by a site-selective oxidative addition of active zinc into a chemically pseudo-equivalent or equivalent carbon-bromine bond, respectively. The subsequent cross-coupling reactions of the organozincs were also successfully carried out under mild conditions providing the corresponding products in moderate to high yields.
- Jung, Hye-Soo,Cho, Hyun-Hee,Kim, Seung-Hoi
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p. 960 - 964
(2013/02/25)
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