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31.
Iuliana-Marilena Andrei Dmytro Strilets Dr. Shixin Fa Marc Baaden Prof. Tomoki Ogoshi Dr. Mihail Barboiu 《Angewandte Chemie (International ed. in English)》2023,62(42):e202310812
Artificial water channels (AWCs) that selectively transport water and reject ions through bilayer membranes have potential to act as synthetic Aquaporins (AQPs). AWCs can have a similar osmotic permeability, better stability, with simpler manufacture on a larger-scale and have higher functional density and surface permeability when inserted into the membrane. Here, we report the screening of combinatorial libraries of symmetrical and unsymmetrical rim-functionalized PAs A – D that are able to transport ca. 107–108 water molecules/s/channel, which is within 1 order of magnitude of AQPs’ and show total ion and proton rejection. Among the four channels, C and D are 3–4 times more water permeable than A and B when inserted in bilayer membranes. The binary combinations of A – D with different molar ratios could be expressed as an independent (linear ABA ), a recessive (inhibition AB , AC , DB , ACA ), or a dominant (amplification, DBD ) behavior of the water net permeation events. 相似文献
32.
Takashi Tamaki Midue Nagata Masato Ohashi Dr. Sensuke Ogoshi Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(39):10083-10091
Cyclopropanecarboxaldehyde ( 1 a ), cyclopropyl methyl ketone ( 1 b ), and cyclopropyl phenyl ketone ( 1 c ) were reacted with [Ni(cod)2] (cod=1,5‐cyclooctadiene) and PBu3 at 100 °C to give η2‐enonenickel complexes ( 2 a – c ). In the presence of PCy3 (Cy=cyclohexyl), 1 a and 1 b reacted with [Ni(cod)2] to give the corresponding μ‐η2:η1‐enonenickel complexes ( 3 a , 3 b ). However, the reaction of 1 c under the same reaction conditions gave a mixture of 3 c and cyclopentane derivatives ( 4 c , 4 c′ ), that is, a [3+2] cycloaddition product of 1 c with (E)‐1‐phenylbut‐2‐en‐1‐one, an isomer of 1 c . In the presence of a catalytic amount of [Ni(cod)2] and PCy3, [3+2] homo‐cycloaddition proceeded to give a mixture of 4 c (76 %) and 4 c′ (17 %). At room temperature, a possible intermediate, 6 c , was observed and isolated by reprecipitation at ?20 °C. In the presence of 1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene (IPr), both 1 a and 1 c rapidly underwent oxidative addition to nickel(0) to give the corresponding six‐membered oxa‐nickelacycles ( 6 ai , 6 ci ). On the other hand, 1 b reacted with nickel(0) to give the corresponding μ‐η2:η1‐enonenickel complex ( 3 bi ). The molecular structures of 6 ai and 6 ci were confirmed by X‐ray crystallography. The molecular structure of 6 ai shows a dimeric η1‐nickelenolate structure. However, the molecular structure of 6 ci shows a monomeric η1‐nickelenolate structure, and the nickel(II) 14‐electron center is regarded as having “an unusual T‐shaped planar” coordination geometry. The insertion of enones into monomeric η1‐nickelenolate complexes 6 c and 6 ci occurred at room temperature to generate η3‐oxa‐allylnickel complexes ( 8 , 9 ), whereas insertion into dimeric η1‐nickelenolate complex 6 ai did not take place. The diastereoselectivity of the insertion of an enone into 6 c having PCy3 as a ligand differs from that into 6 ci having IPr as a ligand. In addition, the stereochemistry of η3‐oxa‐allylnickel complexes having IPr as a ligand is retained during reductive elimination to yield the corresponding [3+2] cycloaddition product, which is consistent with the diastereoselectivity observed in Ni0/IPr‐catalyzed [3+2] cycloaddition reactions of cyclopropyl ketones with enones. In contrast, reductive elimination from the η3‐oxa‐allylnickel having PCy3 as a ligand proceeds with inversion of stereochemistry. This is probably due to rapid isomerization between syn and anti isomers prior to reductive elimination. 相似文献
33.
Cyclopropyl phenyl ketone underwent oxidative addition to Ni(PCy3) generated from Ni(cod)2 and PCy3 to give a nickeladihydropyran, which is a key intermediate for the Ni(0)-catalyzed homo- or heterocycloaddition to give cyclopentane compounds having two carbonyl substituents at the 1,3-position. 相似文献
34.
Ogoshi T Yamafuji D Aoki T Kitajima K Yamagishi TA Hayashi Y Kawauchi S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(24):7493-7500
Planar chiral [2]- and [3]rotaxanes constructed from pillar[5]arenes as wheels and pyridinium derivatives as axles were obtained in high yield using click reactions. The process of rotaxane formation was diastereoselective; the obtained [2]rotaxane was a racemic mixture consisting of (pS, pS, pS, pS, pS) and (pR, pR, pR, pR, pR) forms of the per-ethylated pillar[5]arene (C2) wheel, and other possible types of the [2]rotaxane did not form. Isolation of the enantiopure [2]rotaxanes with one axle through (pS, pS, pS, pS, pS)-C2 or (pR, pR, pR, pR, pR)-C2 wheels was accomplished. Furthermore, pillar[5]arene-based [3]rotaxane was successfully synthesized by attachment of two pseudo [2]rotaxanes onto a bifunctional linker. [3]Rotaxane formed in a 1:2:1 mixture with one axle threaded through two (pS, pS, pS, pS, pS)-C2, one (pS, pS, pS, pS, pS)-C2 and one (pR, pR, pR, pR, pR)-C2 (meso form), or two (pR, pR, pR, pR, pR)-C2 wheels. The [3]rotaxane enantiomers and the meso form were successfully isolated using appropriate chiral HPLC column chromatography. The procedure developed in this study is the starting point for the creation of pillar[5]arene-based interlocked molecules. 相似文献
35.
Tomoki Ogoshi 《Journal of inclusion phenomena and macrocyclic chemistry》2012,72(3-4):247-262
In 2008, we reported a new class of macrocyclic hosts and named “Pillar[5]arenes”. They combine the advantages and aspects of traditional hosts and have a composition similar to those of typical calix[n]arenes. Pillar[5]arenes have repeating units connected by methylene bridges at the para-position, and thus they have a unique symmetrical pillar architecture differing from the basket-shaped structure of meta-bridged calix[n]arenes. Pillar[5]arenes show high functionality similar to cyclodextrins, and can capture electron accepting guest molecules within their cavity similarly to cucurbit[n]urils. In this review, the synthesis, structure, rotation, host–guest properties, planar chirality and functionality of pillar[5]arenes are discussed, along with pillar[5]arene-based supramolecular architectures and the challenges in synthesizing pillar[6]arenes. 相似文献
36.
Soil samples are collected from the former Open Burn/Open Detonation Unit, Makua Military Reservation, on the island of Oahu, Hawaii. The soil is the Helemano series. The soil samples are fortified with eight explosives for development of the analytical method. These analytes are 2-amino-4,6-dinitrotoluene; 1,3-dinitrobenzene; 2,4-dinitrotoluene (DNT); hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX); nitrobenzene (NB); octogen; 1,3,5-trinitrobenzene; and 2,4,6-trinitrotoluene. The analytes are recovered with pressurized fluid extraction and measured with liquid chromatography (LC), LC-mass spectrometry (MS), and gas chromatography-MS. Average recoveries of the seven analytes, except for NB, range from 67% to 110% from freshly fortified samples. The procedure fails to extract NB in soil. The average recoveries decrease from 67-110% to 41-81% as the soil is aged for 1 day to 6 months after fortification of the soil with the seven explosives. The field samples are analyzed for the presence of explosives, of which DNT and RDX are indeed detected. The results obtained with this procedure agree well with those obtained by an independent laboratory following the standard U.S. Environmental Protection Agency (EPA) method SW-846 8330. Compared with the EPA method, this new method provides MS confirmation of the analytes, and the extraction requires approximately 15 min, rather than 18 h by the EPA method. 相似文献
37.
Porous Carbon Fibers Containing Pores with Sizes Controlled at the Ångstrom Level by the Cavity Size of Pillar[6]arene 下载免费PDF全文
Dr. Tomoki Ogoshi Kumiko Yoshikoshi Ryuta Sueto Dr. Hirotomo Nishihara Prof. Tada‐aki Yamagishi 《Angewandte Chemie (International ed. in English)》2015,54(22):6466-6469
We report a new synthesis method of fibrous carbon material with pores sizes that are precisely controlled at the Ångstrom level, by carbonization of two dimensional (2D) porous sheets of pillar[6]arenes. The 2D porous sheets were prepared by 2D supramolecular polymerization induced by oxidation of hydroquinone units of pillar[6]arenes. Owing to the hexagonal structure of pillar[6]arene, the assembly induced by 2D supramolecular polymerization gave hexagonal 2D porous sheets, and the highly ordered structure of the 2D porous sheets formed regular fibrous structures. Then, carbonization of the 2D porous sheets afforded fibrous carbon materials with micropores. The micropore size of the fibrous porous carbon prepared from pillar[6]arene was the same size as that of the starting material pillar[6]arene assembly. 相似文献
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40.
Drake IJ Zhang Y Gilles MK Teris Liu CN Nachimuthu P Perera RC Wakita H Bell AT 《The journal of physical chemistry. B》2006,110(24):11665-11676
Aluminum coordination in the framework of USY and ZSM-5 zeolites containing charge-compensating cations (NH4+, H+, or Cu+) was investigated by Al K-edge EXAFS and XANES. This work was performed using a newly developed in-situ cell designed especially for acquiring soft X-ray absorption data. Both tetrahedrally and octahedrally coordinated Al were observed for hydrated H-USY and H-ZSM-5, in good agreement with 27Al NMR analyses. Upon dehydration, water desorbed from the zeolite, and octahedrally coordinated Al was converted progressively to tetrahedrally coordinated Al. These observations confirmed the hypothesis that the interaction of water with Br?nsted acid protons can lead to octahedral coordination of Al without loss of Al from the zeolite lattice. When H+ is replaced with NH4+ or Cu+, charge compensating species that absorb less water, less octahedrally coordinated Al was observed. Analysis of Al K-edge EXAFS data indicates that the Al-O bond distance for tetrahedrally coordinated Al in dehydrated USY and ZSM-5 is 1.67 angstroms. Simulation of k3chi(k) for Cu+ exchanged ZSM-5 leads to an estimated distance between Cu+ and framework Al atoms of 2.79 angstroms. 相似文献