- Synthesis and Electronic Properties of Donor-Acceptor π-Conjugated Siloles
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An efficient method is presented for the synthesis of novel donor?acceptor silole chromophores through selective monohalogenation of 2,5-dimetallosiloles followed by Negishi alkyne cross-coupling reactions. The electronic properties and crystal packing of
- Boydston,Yin, Youshi,Pagenkopf, Brian L.
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- Synthesis, characterization, electrochemistry, and computational studies of ferrocenyl-substituted siloles
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Ferrocenylsiloles of the type 2,5-Fc2-3,4-Ph2-cC4SiR2 (3a, R = Me; 3b, R = Ph) have been prepared by reductive cyclization from diethynylsilanes, followed by ferrocenylation using the Negishi C,C cross-coupling protocol with the silole ring serving as either the vinyl halogenide species or as the zinc organic component and the complementary functionality introduced on the ferrocenyl moiety. The electrochemical behavior of these silacyclic-bridged bis(ferrocenyl) complexes was investigated by cyclic and square wave voltammetry, and the nature of the redox products was studied by in situ UV-vis-near-IR spectroelectrochemical measurements. 3a,b each undergo two sequential ferrocenyl-based redox processes, the separation of which (δE°′ = δE2°′ - δE1°′ = 300 mV (3a), 280 mV (3b)) is in the range of structural similar systems such as 2,5-diferrocenyl-1-phenyl-1H-phosphole (280 mV) and 2,5-diferrocenylfuran (290 mV). Interestingly, the more electron rich silole 3b, in comparison to 3a, shows a modestly lower redox separation between the individual ferrocenyl oxidation processes, which may be due to the capacity of this group to shield the effect of an adjacent positive charge. An intervalence charge transfer (IVCT) absorption was found in the in situ NIR spectra of [3a]+ and [3b]+, the analysis of which is consistent with a moderate electronic interaction between the iron atoms through the cis-diene-like fragment of the silole bridge, allowing their description as Robin and Day class II mixed-valence systems. These conclusions are supported by results from quantum chemical calculations, which together with NMR studies of 3b, also reveal the likely presence of a range of molecular conformations in solution. (Figure Prsented)
- Lehrich, Steve W.,Hildebrandt, Alexander,Rüffer, Tobias,Korb, Marcus,Low, Paul J.,Lang, Heinrich
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- Siloles and acetenyl aromatics copolymers: Synthesis, characterization and photophysical properties
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Two copolymers, poly(1,1-dimethyl-3,4-diphenylsilole-alt-N-hexyl-3,6-diethynylcarbazole) (PS-DyCz) and poly(1,1-dimethyl-3,4-diphenylsilole-alt-2,7-diethynyl-9,9′-dihexylfluorene) (PS-DyF), were synthesized by Sonogashira coupling reaction of 2,5-dibromo-
- He, Zhenhua,Lai, Guoqiao,Li, Zhifang,Yuan, Xiao,Shen, Yongjia,Wang, Chengyun
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p. 550 - 558
(2015/05/27)
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- Grignard metathesis polymerization and properties of 1,1-disubstituted-2,5- dibromo-3,4-diphenylsiloles
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Grignard metathesis polymerizations of 1,1-disubstituted-2,5-dibromo-3,4- diphenylsiloles such as 1,1-dimethyl-2,5-dibromo-3,4-diphenylsilole, 1,1-diethyl-2,5-dibromo-3,4-diphenylsilole, 1,1-diisopropyl-2,5-dibromo-3,4- diphenylsilole, and 1,1-dihexyl-2,5
- Park, Young Tae
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p. 1825 - 1831
(2014/07/07)
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- Silole-core phenylacetylene dendrimers and their application in detecting picric acid
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Silole-core phenylacetylene dendrimers were designed and synthesized, among them, the model compound (n = 0) and the first generation of the dendrimer (n = 1) were obtained by the reaction of 2,5- dibromosilole with corresponding terminal alkynes, the sec
- Li, Shanshan,Leng, Taohua,Zhong, Hanbin,Wang, Chengyun,Shen, Yongjia
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body text
p. 64 - 70
(2012/04/17)
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- Synthesis, structure, aggregation-induced emission, self-assembly, and electron mobility of 2,5-bis(triphenylsilylethynyl)-3,4-diphenylsiloles
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2,5-Bis(triphenylsilylethynyl)-3,4-diphenylsiloles with different 1,1-substituents [XYSi(CPh)2(C-C≡C-SiPh3) 2] (Ph=phenyl) were synthesized in high yields by the Sonogashira coupling of 2,5-dibromo-3,4-diphenylsiloles with triphenylsilylacetylene, and two of these were characterized crystallographically. Crystal structures and theoretical calculations showed that the new silole molecules had higher conjugation than 2,5-diarylsiloles. They possessed low HOMO and LUMO energy levels due to the electron-withdrawing effect of the triphenylsilylethynyl groups. Cyclic voltammetry analysis revealed low electron affinities, which were comparable to those of perfluoroarylsiloles. B3LYP/6-31* calculations demonstrated that the new siloles possessed large reorganization energies for electron and hole transfers and high electron mobilities. A mobility of up to 1.2 × 10-5 cm2V-1s-1 was obtained by the transient electroluminescence method, which was about fivefold higher than that of tris(8-hydroxyquinolinato)aluminum, a widely used electron-transport material, under the same conditions. All of the silole molecules possessed high thermal stability. Although, their solutions were weakly emissive, their nanoparticle suspensions and thin films emitted intense blue-green light upon photoexcitation, demonstrating a novel feature of aggregation-induced emission (AIE). Polarized emissions were observed in the silole crystals. The addition of solvents, which did not dissolve the silole molecules, into silole-containing solutions caused self-assembly of the molecules, which produced macroscopic fibrils with strong light emissions. Copyright
- Zhao, Zujin,Liu, Dandan,Mahtab, Faisal,Xin, Linyuan,Shen, Zhongfang,Yu, Yong,Chan, Carrie Y. K.,Lu, Ping,Lam, Jacky W. Y.,Sung, Herman H. Y.,Williams, Ian D.,Yang, Bing,Ma, Yuguang,Tang, Ben Zhong
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supporting information; experimental part
p. 5998 - 6008
(2011/07/07)
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