133005-88-6Relevant articles and documents
Dual-colored 4,4′,4′′,4′′′-(cyclobutane-1,2,3,4-tetrayl)-tetrabenzoate electrochromic materials with large optical contrast and coloration efficiency
Zhu, Chun-Rong,Xie, Jia-Ping,Mou, Hong-Rong,Huang, Zhen-Jie,Tang, Qian,Gong, Cheng-Bin,Fu, Xiang-Kai
, p. 13654 - 13661 (2019/09/06)
Nine 4,4′,4′′,4′′′-(cyclobutane-1,2,3,4-tetrayl)tetrabenzoate derivative electrochromic materials have been designed, synthesized, and characterized. Seven compounds displayed dual-colored electrochromism. The required potential and colored states were markedly influenced by substitution. When the substituent was alkyl, colored states of purple and blue were obtained at an applied voltage of -2.3 and -2.6 V, respectively; when the substituent was phenyl with an electron-donating group, colored states of purple bluish and bright blue were obtained at an applied voltage of -2.1 and -2.3 V, respectively; when the substituent was phenyl with an electron-withdrawing group, monocolored state and bad electrochromic properties were obtained. Moreover, electrochromic devices based on most of these compounds show large optical contrast, fast response time, and high coloration efficiency.
Mechanistic studies on the Pd-catalyzed vinylation of aryl halides with vinylalkoxysilanes in water: The effect of the solvent and NaOH promoter
Gordillo, Alvaro,Ortuno, Manuel A.,Lopez-Mardomingo, Carmen,Lledos, Agusti,Ujaque, Gregori,De Jesus, Ernesto
supporting information, p. 13749 - 13763 (2013/10/01)
The mechanism of the Pd-catalyzed vinylation of aryl halides with vinylalkoxysilanes in water has been studied using different catalytic precursors. The NaOH promoter converts the initial vinylalkoxysilane into a highly reactive water-soluble vinylsilanolate species. Similarly, deuterium-labeling experiments have shown that, irrespective of the catalytic precursor used, vinylation occurs exclusively at the CH vinylic functionality via a Heck reaction and not at the C-Si bond via a Hiyama cross-coupling. The involvement of a Heck mechanism is interpreted in terms of the reduced nucleophilicity of the base in water, which disfavors the transmetalation step. The Heck product (β-silylvinylarene) undergoes partial desilylation, with formation of a vinylarene, by three different routes: (a) hydrolytic desilylation by the aqueous solvent (only at high temperature); (b) transmetalation of the silyl olefin on the PdH Heck intermediate followed by reductive elimination of vinylarene; (c) reinsertion of the silyl olefin into the PdH bond of the Heck intermediate followed by β-Si syn-elimination. Both the Hiyama and Heck catalytic cycles and desilylation mechanisms b and c have been computationally evaluated for the [Pd(en)Cl2] precursor in water as solvent. The calculated Gibbs energy barriers support the reinsertion route proposed on the basis of the experimental results.
External stimulus-responsive supramolecular structures formed by a stilbene cyclodextrin dimer
Kuad, Paul,Miyawaki, Atsuhisa,Takashima, Yoshinori,Yamaguchi, Hiroyasu,Harada, Akira
, p. 12630 - 12631 (2008/03/13)
Cyclodextrin (CD) based supramolecular complexes have been prepared using a stilbene bis(β-CD) dimer and a ditopic adamantyl guest. The conformation of the stilbene bis(β-CD) dimer in aqueous solutions could be photochemically controlled. The ROESY spectra of the β-CD dimer with the adamantyl dimer showed NOE between the protons of adamantyl moieties and the inner protons of the CD. When the host cyclodextrin dimer was in trans conformation, supramolecular dimers or small assemblies are formed in solutions, whereas in its cis conformation supramolecular linear polymers with high molecular weight were observed. Thus the structure of the supramolecular polymers could be controlled by an external stimulus. Copyright
