150-78-7Relevant articles and documents
Charge-transfer complex formations of tetracyanoquinone (cyanil) and aromatic electron donors
Jalilov, Almaz S.,Lu, Jianjiang,Kochi, Jay K.
, p. 35 - 41 (2016)
Single-electron oxidants are the primary reagents for investigations of the new oxidants and the development of electron-accepting materials for application in optoelectronics. Quinones are the well-known class of the neutral single-electron oxidants. Here, we present the properties of the strongest neutral electron acceptor of this class tetracyanoquinone (cyanil) and investigate its electron-accepting strength by analyzing the charge-transfer complex formations with the aromatic donor molecules. Charge-transfer complexes of tetracyanoquinone with aromatic electron donors are characterized spectroscopically in solution and isolated as the single crystals.
Photo-Switchable Self-Assemblies Based on Thymine-Containing Bolaamphiphiles
Al-Shereiqi, Ahmed S.,Boyd, Ben J.,Saito, Kei
, p. 1135 - 1144 (2017)
The photoswitching of photosensitive bolaamphiphiles based on thymine was investigated. Topochemical principles were applied to create light-responsive supra-amphiphiles by the utilisation of dynamic covalent bonds created by the photo-dimerisation of a DNA base, thymine. In order to induce the photo-dimerisation of thymine, two bolaamphiphilic molecules were designed and synthesised to meet the required [2 π+2 π] photo-cycloaddition conditions. The amphiphiles were synthesised with different spacers and their photo-reversibility and morphologies were studied by using UV/Vis, NMR and infrared spectroscopy, rheometry, dynamic light scattering and transmission electron microscopy.
A second-generation dendrimer with six 2,9-dimethyl-1,10-phenanthroline units as ligand for copper-catalyzed reactions
Lüning, Ulrich,Eggert, Jan P. W.,Hagemann, Kathrin
, p. 2747 - 2752 (2006)
2,9-Dimethyl-1,10-phenanthroline (neocuproine, 1) has been attached to dendritic structures through its 5-position providing a trimer 7 and the hexamers 11 and 12. The copper-binding capability of the hexamer 12 has been studied, and the 6:1 complex has been used to catalyze the Cu +-promoted substitution of an iodoarene 14 to give an aryl ether 15. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Pulse Radiolytic Investigations of Aqueous Solutions of Methoxybenzene Cation Radicals: The Effect of Colloidal RuO2
Brandys, Marek,Sasson, Richard E.,Rabani, Joseph
, p. 953 - 962 (1987)
The formation and decay of the radical cations of 1,4-dimethoxybenzene (DMB) and 1,2,4,5-tetramethoxybenzene (TMB) were investigated by the pulse radiolysis technique in the absence and the presence of colloidal RuO2 particles.DMB2. was obtained only by T12+ oxidation of DMB while TMB+.+ was produced by oxidation of TMB using both T12+ and Br2-.In the absence of RuO2 both DMB.+ and TMB.+ decay predominantly via a second-order process, although there is a contribution of a pseudo-first-order reaction.The rate constants for these reactions are reported.RuO2 colloidal particles catalyze the decay of both TMB.+ and DMB.+.The reactions of TMB.+ with RuO2 were found to depend on pH, pulse intensity, and colloidal concentration.At pH 3-4, adsorbtion of TMB.+ to the colloid is observed, followed by the decay of the remaining TMB.+ in the bulk.At higher pHs, loading of the RuO2 colloid by positive holes takes place until equilibrium is archieved between loaded holes and TMB.+ and again the remaining TMB.+ decays at a later stage.The fraction of TMB.+ that loads the colloidal particles increases with both pH and .It is also suggested that DMB.+ loads the RuO2 at the pH where experiments were performed. (TMB)2 and (DMB)2 dimers (or higher oligomers) are suggested to be the final products both in absence and presence of RuO2.No O2 is formed with the RuO2 colloid despite a favorable redox potential for water oxidation.
Intramolecular hydrogen bonding and molecular structure of 2,5-dihydroxyterephthalaldehyde and 4,6-dihydroxyisophthalaldehyde: A gas-phase electron diffraction and ab initio molecular orbital study
Borisenko, Konstantin B.,Zauer, Karoly,Hargittai, Istvan
, p. 19303 - 19309 (1996)
The molecular structure of 2,5-dihydroxyterephthalaldehyde has been determined from a joint electron diffraction/ab initio investigation, and the molecular structure of 4,6-dihydroxyisophthalaldehyde has been obtained from ab initio calculations at the MP2/6-31G* level. There is considerable intramolecular hydrogen bonding in these structures manifested by the O...H and O...O distances as well as by the structural changes in the rest of the molecule. These changes are consistent with the notion of resonance-assisted hydrogen bonding. The hydrogen bonding is somewhat stronger in 4,6-dihydroxyisophthalaldehyde than in 2,5-dihydroxyterephthalaldehyde, and this difference may be linked to the difference in the mutual positioning of the interacting formyl and hydroxy groups in these molecules.
Photogeneration of Radical Cations from Aqueous Methoxylated Benzenes
Grabner, Gottfried,Rauscher, Walter,Zechner, Josef,Getoff, Nikola
, p. 222 - 223 (1980)
Formation of radical cations resulting from photoinduced electron ejection from methoxylated benzenes in aqueous solutions has been observed.
Hollow, mesoporous, eutectic Zn1?xMgxO nano-spheres as solid acid-base catalysts for the highly regio-selectiveO-methylation of 1,2-diphenols
Liu, Jie,Ma, Xuebing,Wang, Xuri,Xie, Guangxin,Yin, Zuyong,Zhang, Jianing
, p. 7454 - 7466 (2021/11/23)
The highly regio-selectiveO-methylation of catechol with dimethyl carbonate (DMC), catalyzed by a solid acid-base catalyst, is an environmentally friendly chemical process for industrial production of guaiacol. However, a guaiacol yield below 84% and high reaction temperature above 280 °C limit its industrial application. Here, hollow, mesoporous Zn1?xMgxO nano-spheres with a eutectic structure, denoted as Zn1?xMgxO HMNSs (x= 0.012-0.089), are facilely fabricatedviathe calcination of Mg2+/Zn2+ion-adsorbing carbon spheres at 500 °C in air. In theO-methylation of catechol with DMC at 180 °C, Zn1?xMgxO HMNSs (x= 0.052) afford guaiacol in 95.5% yield with a complete catechol conversion. Furthermore, 89.0-95.3% mono-ether yields with high 1,2-diphenol conversions (94.5-100%) are also obtained for the other 1,2-diphenols bearing -CH3and -Br groups. Moreover, a plausible mechanism for highly selectiveO-methylation of catechol with DMC is proposed, in which the single-site activation and double-site activation of phenolic hydroxyls by the basic oxygen of Mg-O afford guaiacol and veratrole, respectively.
A highly stable all-in-one photocatalyst for aryl etherification: The NiIIembedded covalent organic framework
Chen, Hao,Dong, Wenbo,Hu, Jianxiang,Rao, Li,Wang, Pei,Wang, Shengyao,Xiang, Yonggang,Yang, Yi
, p. 5797 - 5805 (2021/08/23)
The efficient conversion of aryl bromides to the corresponding aryl alkyl ethers by dual nickel/photocatalysis has seen great progress, but difficulties of recycling the photosensitizer or nickel complexes cause problems of sustainability. Here, we report the design of a novel, highly stable vinyl bridge 2D covalent organic framework (COF) containing Ni, which combines the role of photosensitizer and reactive site. The as-prepared sp2c-COFdpy-Ni acts as an efficient heterogeneous photocatalyst for C-O cross coupling. The sp2c-COFdpy-Ni can be completely recovered and used repeatedly without loss of activity, overcoming the limitations of the prior methods. Preliminary studies reveal that strong interlayer electron transfer may facilitate the generation of the proposed intermediate sp2c-COFdpy-NiI in a bimolecular and self-sustained manner. This all-in-one heterogeneous photocatalyst exhibits good compatibility of substrates and tolerance of functional groups. The successful attempt to expand the 2D COFs with this new catalyst into photocatalytic organic transformation opens an avenue for photoredox/transition metal mediated coupling reactions.
Copper-Catalyzed Methoxylation of Aryl Bromides with 9-BBN-OMe
Li, Chen,Song, Zhi-Qiang,Wang, Dong-Hui,Wang, Jing-Ru
supporting information, p. 8450 - 8454 (2021/11/17)
A Cu-catalyzed cross-coupling reaction between aryl bromides and 9-BBN-OMe to provide aryl methyl ethers under mild conditions is reported. The oxalamide ligand BHMPO plays a key role in the transformation. Various functional groups on bromobenzenes are well tolerated, providing the desired anisole products in moderate to high yields.
B(C6F5)3-Catalyzed Hydroarylation of Aryl Alkynes for the Synthesis of 1,1-Diaryl and Triaryl Substituted Alkenes
Chen, Hui,Gao, Liuzhou,Liu, Xueting,Wang, Guoqiang,Li, Shuhua
supporting information, p. 5238 - 5242 (2021/10/19)
A new strategy for the synthesis of 1,1-diaryl and triarylsubstituted alkenes has been developed utilizing B(C6F5)3-catalyzed hydroarylation of alkynes with phenols. The method provides a direct route to ortho-alkenylated phenols with both terminal and internal alkynes. The reactions show excellent regioselectivity, and good stereoselectivity was observed for the hydroarylation of internal alkynes. Computational and experimental studies suggest that for the reaction of internal alkynes and phenols, an acid-catalyzed isomerization mechanism involving two tertiary carbonium ion intermediates is responsible for the formation of Z-triaryl substituted alkenes.
