- Porous organic polymer supported rhodium as a heterogeneous catalyst for hydroformylation of alkynes to α,β-unsaturated aldehydes
-
A new porous organic polymer supported rhodium catalyst (Rh/POL-BINAPa&PPh3) has been developed for the hydroformylation of various alkynes to afford the corresponding α,β-unsaturated aldehydes with high chem- and stereoselectivity, excellent catalytic activity and good reusability (10 cycles). The heterogeneous catalyst exhibited more catalytic activity than the comparable homogeneous Rh/BINAPa/PPh3 system.
- Liang, Zuyu,Chen, Jianbin,Chen, Xin,Zhang, Kai,Lv, Jinhe,Zhao, Haowen,Zhang, Guoying,Xie, Congxia,Zong, Lingbo,Jia, Xiaofei
-
supporting information
p. 13721 - 13724
(2019/11/19)
-
- The role of electron-transporting Benzo[f]quinoline unit as an electron acceptor of new bipolar hosts for green PHOLEDs
-
We prepared three new compounds [3,6-di(9H-carbazol-9-yl)phenanthrene (3,6-DCP), 2,9-di(9H-carbazol-9-yl)benzo[f]quinoline (2,9-DCBQ), and 3,9-di(9H-carbazol-9-yl)benzo[f]-quinoline (3,9-DCBQ)] containing phenanthrene or benzo[f]quinoline as an electron-withdrawing moiety and a carbazole as electron-donating moiety, respectively, as bipolar hosts for green phosphorescent organic light emitting diodes (PHOLEDs). We intentionally substituted nitrogen atom to the C-3 position of phenanthrene moiety to prepare benzo[f]quinolinegroup. And, we found that it allowed better electron transporting behavior than the phenanthrene moiety. Meanwhile, the benzo[f]quinoline/phenanthrene core moieties significantly improved the thermal stability of those host materials, which exhibited glass transition and decomposition temperatures of 132–139 and 395–427 °C, respectively. The green PHOLEDs which were fabricated with those host materials showed the lowest operating voltage of 4.7 V at 1000 cd/m2 when we used 3,9-DCBQ. Very interestingly, it has an asymmetric structure with completely separated HOMO and LUMO in space. In contrast, 3,6-DCP having phenanthrene and carbazole moieties showed much higher operating voltage of 6.1 V which imply that replacing nitrogen at the C-3 position of phenanthrene improves carrier transport, that is, electron transporting behavior. As a result, the 3,9-DCBQ-based PHOLED showed the best overall performance, exhibiting current and power efficiencies of 48.5 cd/A and 20.6 lm/W, respectively.
- Seo, Junseok,Park, So-Ra,Kim, Mina,Suh, Min Chul,Lee, Jihoon
-
p. 959 - 966
(2018/11/26)
-
- Encapsulation of Hoveyda-Grubbs2nd Catalyst within Yolk-Shell Structured Silica for Olefin Metathesis
-
Through postreducing the pore size of a mesoporous shell, Hoveyda-Grubbs2nd catalyst was successfully encapsulated within yolk-shell structured silica, leading to a heterogeneous catalyst for olefin metathesis. Such a catalyst exhibits much higher activity than the reported encapsulated catalysts in olefin ring-closing metathesis and cross metathesis. This excellent activity can be attributed to the combination of a hollow structure in the interior and permeable mesopores in the shells. This catalyst shows good recyclability, highlighted by eight cycles of reaction. This work not only supplies an excellent heterogeneous olefin metathesis catalyst but also demonstrates that yolk-shell structured silica materials can be used as an innovative scaffold to encapsulate homogeneous catalysts.
- Li, Qibiao,Zhou, Ting,Yang, Hengquan
-
p. 2225 - 2231
(2015/04/14)
-
- Synthesis of combretastatin A-4 O-alkyl derivatives and evaluation of their cytotoxic, antiangiogenic and antitelomerase activity Dedicated to Professor G. Asensio, University of Valencia, on the occasion of his 65th birthday
-
We here report the synthesis and biological evaluation of several combretastatin A-4 derivatives alkylated at the phenol hydroxyl group. Some of these derivatives contain an (E)-arylalkene fragment reminiscent of that present in some natural stilbenes like resveratrol. The cytotoxicities towards one human healthy kidney embryonic and two tumoral cell lines were determined. In addition, the ability of these compounds to inhibit the production of the vascular endothelial growth factor (VEGF) was measured. Finally, the expression of genes controlling the production of telomerase was measured. Some of the compounds were found to have an activity comparable or higher than that of combretastatin A-4 in at least one of the aforementioned biological properties. The compounds with the (E)-arylalkene fragment were in general terms more active than the simple O-alkyl derivatives. However, no clear structure/activity correlations were perceived when comparing the observed compound activities across the three biological properties. This points out the existence of marked differences between the mechanisms responsible for their cytotoxicity.
- Torijano-Gutiérrez, Sandra,Díaz-Oltra, Santiago,Falomir, Eva,Murga, Juan,Carda, Miguel,Marco, J. Alberto
-
p. 7267 - 7274
(2013/11/19)
-
- Encapsulation of an olefin metathesis catalyst in the nanocages of SBA-1: Facile preparation, high encapsulation efficiency, and high activity
-
By postreducing the window size through silylation, 2nd generation Hoveyda-Grubbs catalyst was encapsulated in the nanocages of a mesoporous material SBA-1. The encapsulation efficiency of SBA-1 was up to 70%, much higher than that of other mesoporous materials such as SBA-16, FDU-12, and MCM-41 (0-43%). The successful encapsulation was confirmed by N2 sorption analysis and FTIR and diffusion reflectance UV/Vis spectroscopy. Such a SBA-1-encapsulated catalyst showed good activity in both olefin ring-closing metathesis and cross metathesis. A wide range of olefins could be transformed to the desired products with conversions of 27-100%. The encapsulated catalyst showed more sensitive temperature effects than the homogeneous counterpart, reflecting the unique properties of the encapsulated catalyst. At reaction temperatures of 40-60°C, the activity of the encapsulated catalyst was sufficiently comparable to that of the homogeneous catalyst for the cross metathesis of styrene-type substrates, probably because of the confinement effects of the nanocages. The solid catalyst could be recycled seven times. This study not only supplies a new solid catalyst for olefin metathesis but also demonstrates our improvement in immobilizing metal complex catalyst toward a green and effective level.
- Yang, Hengquan,Ma, Zhancheng,Zhou, Ting,Zhang, Wenjuan,Chao, Jianbin,Qin, Yong
-
p. 2278 - 2287
(2013/08/23)
-
- AROMATIC AMINE DERIVATIVE AND ORGANIC ELECTROLUMINESCENCE DEVICE USING THE SAME
-
To attain an organic electroluminescence device having a long lifetime and high luminous efficiency, and is capable of emitting blue light having a high color purity, and an aromatic amine derivative for realizing the device, the present invention provide
- -
-
Page/Page column 62
(2008/06/13)
-
- Synthesis of stilbenes via homocoupling of aryl aldehyde tosylhydrazones
-
Stilbenes are readily prepared in good yields via homocoupling of aryl aldehyde tosylhydrazones in the presence of lithium tert-butoxide and trimethyl borate under reflux in THF.
- Kabalka, George W,Wu, Zhongzhi,Ju, Yuhong
-
p. 4759 - 4760
(2007/10/03)
-
- Substituent Effect Studies of Aryl-Assisted Solvolyses. I. The Acetolysis of 2,2-Bis(substituted phenyl)ethyl p-Toluenesulfonates
-
The substituent effect on the acetolysis of 2,2-bis(substituted phenyl)ethyl p-toluenesulfonates at 90.10 deg C can be described accurately in terms of the Yukawa-Tsuno (LArSR) relationship, giving a ρ value of -4.44 and an r value of 0.53. The substituent effect correlation of this system carrying two aryls is quite comparable to that of the 2-methyl-2-phenylpropyl system carrying a single aryl group, suggesting the close similarity in the structure of the transition states between the systems. The results can be reasonably accounted for on the basis of the accepted mechanism of this reaction, involving a rate-determining aryl-assisted transition state where only one aryl group of the two β-aryl groups participates.
- Fujio, Mizue,Maeda, Yasuyuki,Goto, Mutsuo,Saeki, Yoshihiro,Mishima, Masaaki,Tsuno, Yuho
-
p. 3015 - 3020
(2007/10/02)
-
- Effects of Salt on Isomerization of Stilbene Cation Radicals. Direct Observation of their Cis -> Trans Conversion
-
Unimolecular cis-trans conversion of stilbene cation radicals generated from 9,10-dicyanoanthracene-biphenyl co-sensitization under air was directly observed in the presence of salt such as LiClO4 in acetonitrile, and the activation parameters of this pro
- Kuriyama, Yasunao,Arai, Tatsuo,Sakuragi, Hirochika,Tokumaru, Katsumi
-
p. 879 - 882
(2007/10/02)
-