- Cage structure helps to improve the photoisomerization efficiency of azobenzene
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Azobenzene (Azo) usually cannot achieve relatively high photoisomerization efficiency because of the overlap of the n-π* absorption bands between their isomers. In this work, three Azo units were integrated into a cage (AC) and adopt a nonplanar configura
- Yuan, Tao,Wang, Zhi-Qiang,Gong, Xue-Qing,Wang, Qiaochun
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supporting information
(2020/11/19)
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- A Polymorphic Azobenzene Cage for Energy-Efficient and Highly Selective p-Xylene Separation
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Developing the competence of molecular sorbents for energy-saving applications, such as C8 separations, requires efficient, stable, scalable, and easily recyclable materials that can readily transition to commercial implementation. Herein, we report an azobenzene-based cage for the selective separation of p-xylene isomer across a range of C8 isomers in both vapor and liquid states with selectivity that is higher than the reported all-organic sorbents. The crystal structure shows non-porous cages that are separated by p-xylene molecules through selective CH–π interactions between the azo bonds and the methyl hydrogen atoms of the xylene molecules. This cage is stable in solution and can be regenerated directly under vacuum to be used in multiple cycles. We envisage that this work will promote the investigation of the azo bond as well as guest-induced crystal-to-crystal phase transition in non-porous organic solids for energy-intensive separations.
- Alimi, Lukman O.,Bhatt, Prashant M.,Eddaoudi, Mohamed,Fakim, Aliyah,Khashab, Niveen M.,Moosa, Basem,Shkurenko, Aleksander,Zhang, Gengwu
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supporting information
p. 21367 - 21371
(2020/10/06)
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- Air-Stable Gold Nanoparticles Ligated by Secondary Phosphine Oxides as Catalyst for the Chemoselective Hydrogenation of Substituted Aldehydes: A Remarkable Ligand Effect
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Air-stable and homogeneous gold nanoparticles (AuNPs, 1a-5a) ligated by various secondary phosphine oxides (SPOs), [R1R2P(O)H] (R1 = Naph, R2 = tBu, L1; R1 = R2 = Ph, L2; R1 = Ph, R2 = Naph, L3; R1 = R2 = Et, L4; R1 = R2 = Cy, L5; R1 = R2 = tBu, L6), with different electronic and steric properties were synthesized via NaBH4 reduction of the corresponding Au(I)-SPO complex. These easily accessible ligands allow the formation of well dispersed and small nanoparticles (size 1.2-2.2 nm), which were characterized by the use of a wide variety of techniques, such as transmission electron microscopy, thermogravimetric analysis, UV-vis, energy-dispersive X-ray, X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR), and cross polarization magic angle spinning (CP MAS) NMR spectroscopy. A pronounced ligand effect was found, and CP MAS NMR experiments enabled us to probe important differences in the polarity of the P-O bond of the SPOs coordinated to the nanoparticle surface depending on the type of substituents in the ligand. AuNPs containing aryl SPOs carry only SPO anions and are highly selective for aldehyde hydrogenation. AuNPs of similar size made with alkyl SPOs contain also SPOH, hydrogen bonded to SPO anions. As a consequence they contain less Au(I) and more Au(0), as is also evidenced by XPS. They are less selective and active in aldehyde hydrogenation and now show the typical activity of Au(0)NPs in nitro group hydrogenation. (Chemical Equation Presented).
- Cano, Israel,Huertos, Miguel A.,Chapman, Andrew M.,Buntkowsky, Gerd,Gutmann, Torsten,Groszewicz, Pedro B.,Van Leeuwen, Piet W. N. M.
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supporting information
p. 7718 - 7727
(2015/07/01)
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- Visible light mediated homo- and heterocoupling of benzyl alcohols and benzyl amines on polycrystalline cadmium sulfide
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The oxidative coupling of sp3 hybridized carbon atoms by photocatalysis is a valuable synthetic method as stoichiometric oxidation reagents can be avoided and dihydrogen is the only byproduct of the reaction. Cadmium sulfide, a readily available semiconductor, was used as a visible light heterogeneous photocatalyst for the oxidative coupling of benzyl alcohols and benzyl amines by irradiation with blue light. Depending on the structure of the starting material, good to excellent yields of homocoupling products were obtained as mixtures of diastereomers. Cross-coupling between benzyl alcohols and benzyl amines gave product mixtures, but was selective for the coupling of tetrahydroisoquinolines to nitromethane. The results demonstrate that CdS is a suitable visible light photocatalyst for oxidative bond formation under anaerobic conditions.
- Mitkina, Tatiana,Stanglmair, Christoph,Setzer, Wolfgang,Gruber, Michael,Kisch, Horst,Koenig, Burkhard
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supporting information; experimental part
p. 3556 - 3561
(2012/06/01)
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- Novel compounds for the prophylaxis and treatment of inflammatory bowel diseases
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Novel compounds are disclosed for the prophylaxis and treatment of inflammatory bowel disease (IBD) via the administration of an effective amount in a suitable pharmaceutical dosage of agents that are active by themselves or can deliver tin the large intestine active forms of the drugs such as 5ASA or benzoxazole acetic acid or platelet activating factors. The mechanism of the release is based on bacterial cleavage of an azo linkage in the mammalian lower bowel to release the active compound(s).
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Page/Page column 5
(2010/11/25)
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- Benzoxazole derivatives for the prophylaxis and treatment of inflammatory bowel diseases
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The present invention relates to novel compounds for the prophylaxis and treatment of inflammatory bowel disease (IBD) via the administration of an effective amount in a suitable pharmaceutical dosage of agents that are active by themselves or can deliver tin the large intestine active forms of the drugs such as 5ASA or benzoxazole acetic acid or platelet activating factors. The mechanism of the release is based on bacterial cleavage of an azo linkage in the mammalian lower bowel to release the active compound(s).
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Page/Page column 7; 10
(2010/11/23)
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- One-pot synthesis of terpyridines and macrocyclization to C3-symmetric cyclosexipyridines
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Four examples of 2,6-dicinnamoylpyridines were obtained in 60-65% yields in condensations of commercially available 2,6-diacetylpyridine and benzaldehydes in 1:2 stoichiometry. At 2:1 ratios, four related 6,6″-diacetylated-4′-arylterpyridines were isolate
- Masciello, Lucie,Potvin, Pierre G.
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p. 209 - 218
(2007/10/03)
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- Chemoselective reductive coupling of nitroarenes with magnesium in methanol via single electron transfer
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A chemoselective reductive coupling of nitroarenes using magnesium in methanol has been reported at ambient temperature. While the cyano, formyl, methoxycarbonyl, methyl, methoxy, phenyl, amino, and chloro groups are unaffected, iodo and bromo groups undergo dehalogenation but in a slower reaction than the coupling of nitro group. The coupling is believed to be proceeding via SET from Mg to nitroarenes.
- Khurana, Jitender M.,Ray, Abhijit
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p. 407 - 410
(2007/10/03)
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