- A Cu(II)-MOF capable of fixing CO2 from air and showing high capacity H2 and CO2 adsorption
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A porous Cu(ii)-MOF shows an adsorption of 6.6 wt% of H2 at 77 K and 62 bar and a very high 60 wt% of CO2 at 298 K and 32 bar. When air is bubbled into a suspension of the activated MOF in the presence of different epoxides at room temperature, the CO2 in air is readily converted into the corresponding cyclic carbonates.
- Sharma, Vivekanand,De, Dinesh,Saha, Ranajit,Das, Ranjita,Chattaraj, Pratim Kumar,Bharadwaj, Parimal K.
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Read Online
- Highly Efficient and Chemoselective Hydrogenation of Nitro Compounds into Amines by Nitrogen-Doped Porous Carbon-Supported Co/Ni Bimetallic Nanoparticles
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A novel Co/Ni bimetallic nanoparticle supported by nitrogen-doped porous carbon (NPC), Co5/Ni@NPC-700, exhibits high conversion, chemoselectivity, and recyclability in the hydrogenation of 16 different nitro compounds into desired amines with hydrazine hydrate under mild conditions. The synergistic effects of Co/Ni bimetal nanoparticles and the NPC-supported porous honeycomb structure with more accessible active sites may be responsible for the high catalytic hydrogenation performance.
- Shen, Zeyu,Hong, Lirui,Zheng, Baishu,Wang, Guanyu,Zhang, Beibei,Wang, Zhaoxu,Zhan, Feiyang,Shen, Shaohua,Yun, Ruirui
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supporting information
p. 16834 - 16839
(2021/11/17)
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- Fe/Fe3C Encapsulated in N-Doped Carbon Tubes: A Recyclable Catalyst for Hydrogenation with High Selectivity
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Herein, a series of Fe-based catalysts have been designed and prepared by grinding a mixture of MIL-88d and melamine, and then the mixture was followed by pyrolysis. An unusual Fe/Fe3C-activated site is uniformly encapsulated in the N-doped carbon tubes obtained by pyrolysis of the film-like nanocrystals of MIL-88d. Experimental characterizations and theoretical calculations demonstrate that the surface N sites can effectively trap the nitrobenzene and aniline by their phenyl groups with the formation of three C-N bonds that made the catalyst exhibit excellent catalytic activity (turnover frequencies of ≤11268 h-1 calculated on the basis of nitrobenzene) and chemoselectivity for the reduction of nitro derivatives under facile conditions.
- Yun, Ruirui,Zhang, Shi,Ma, Wanjiao,Lv, Xiao,Liu, Shoujie,Sheng, Tian,Wang, Suna
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supporting information
p. 9469 - 9475
(2019/08/20)
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- Simple Nickel Salts for the Amination of (Hetero)aryl Bromides and Iodides with Lithium Bis(trimethylsilyl)amide
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Recent developments in the chemistry of C-N bond formation and the synthesis of anilines have allowed for the use of first-row transition metals to catalyze these transformations. Much of the progress in this area has been driven by comprehensive screening for privileged/tailored ligands, which can be costly and not readily available in a research laboratory setting. In this communication we report a protocol in which simple nickel salts catalyze the C-N cross-coupling reaction between (hetero)aryl bromides and iodides with lithium bis(trimethylsilyl)amide without the need for any additive ligand. This method is amenable to low nickel catalyst loadings (1%) as well as gram-scale reactions. Because of the good functional group tolerance and compatibility with heterocyclic moieties, this method is useful for academic laboratory settings where access to tailored ligands and noble-metal catalysts could be challenging.
- Martinez, Gabriel Espinosa,Nugent, Joseph W.,Fout, Alison R.
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supporting information
p. 2941 - 2944
(2018/09/21)
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- FHBC, a Hexa-peri-hexabenzocoronene–Fluorene Hybrid: A Platform for Highly Soluble, Easily Functionalizable HBCs with an Expanded Graphitic Core
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Materials based upon hexa-peri-hexabenzocoronenes (HBCs) show significant promise in a variety of photovoltaic applications. There remains the need, however, for a soluble, versatile, HBC-based platform, which can be tailored by incorporation of electroactive groups or groups that can prompt self-assembly. The synthesis of a HBC–fluorene hybrid is presented that contains an expanded graphitic core that is highly soluble, resists aggregation, and can be readily functionalized at its vertices. This new HBC platform can be tailored to incorporate six electroactive groups at its vertices, as exemplified by a facile synthesis of a representative hexaaryl derivative of FHBC. Synthesis of new FHBC derivatives, containing electroactive functional groups that can allow controlled self-assembly, may serve as potential long-range charge-transfer materials for photovoltaic applications.
- Navale, Tushar S.,Ivanov, Maxim V.,Hossain, Mohammad M.,Rathore, Rajendra
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p. 790 - 794
(2017/12/26)
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- A curcumin-based molecular probe for near-infrared fluorescence imaging of tau fibrils in Alzheimer's disease
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In recent years, there has been growing interest in the near-infrared (NIR) fluorescence imaging of tau fibrils for the early diagnosis of Alzheimer's disease (AD). In order to develop a curcumin-based NIR fluorescent probe for tau fibrils, structural modification of the curcumin scaffold was attempted by combining the following rationales: the curcumin derivative should preserve its binding affinity to tau fibrils, and, upon binding to tau fibrils, the probe should show favorable fluorescence properties. To meet these requirements, we designed a novel curcumin scaffold with various aromatic substituents. Among the series, the curcumin derivative 1c with a (4-dimethylamino-2,6-dimethoxy)phenyl moiety showed a significant change in its fluorescence properties (22.9-fold increase in quantum yield; Kd, 0.77 μM; λem, 620 nm; Φ, 0.32) after binding to tau fibrils. In addition, fluorescence imaging of tau-green fluorescent protein-transfected SHSY-5Y cells with 1c confirmed that 1c detected tau fibrils in live cells.
- Park, Kwang-Su,Seo, Yujin,Kim, Mi Kyoung,Kim, Kyungdo,Kim, Yun Kyung,Choo, Hyunah,Chong, Youhoon
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p. 11194 - 11199
(2015/11/27)
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- Attraction or Repulsion? London Dispersion Forces Control Azobenzene Switches
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Large substituents are commonly seen as entirely repulsive through steric hindrance. Such groups have additional attractive effects arising from weak London dispersion forces between the neutral atoms. Steric interactions are recognized to have a strong influence on isomerization processes, such as in azobenzene-based molecular switches. Textbooks indicate that steric hindrance destabilizes the Z isomers. Herein, we demonstrate that increasing the bulkiness of electronically equal substituents in the meta-position decreases the thermal reaction rates from the Z to the E isomers. DFT computations revealed that attractive dispersion forces essentially lower the energy of the Z isomers.
- Schweighauser, Luca,Strauss, Marcel A.,Bellotto, Silvia,Wegner, Hermann A.
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supporting information
p. 13436 - 13439
(2015/11/09)
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- Elusive metal-free primary amination of arylboronic acids: Synthetic studies and mechanism by density functional theory
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Herein, we disclose the first metal-free synthesis of primary aromatic amines from arylboronic acids, a reaction that has eluded synthetic chemists for decades. This remarkable transformation affords structurally diverse primary arylamines in good chemical yields, including a variety of halogenated primary anilines that often cannot be prepared via transition-metal-catalyzed amination. The reaction is operationally simple, requires only a slight excess of aminating agent, proceeds under neutral or basic conditions, and, importantly, can be scaled up to provide multigram quantities of primary anilines. Density functional calculations reveal that the most likely mechanism involves a facile 1,2-aryl migration and that the presence of an ortho nitro group in the aminating agent plays a critical role in lowering the free energy barrier of the 1,2-aryl migration step.
- Zhu, Chen,Li, Gongqiang,Ess, Daniel H.,Falck, John R.,Kürti, László
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supporting information
p. 18253 - 18256
(2013/01/15)
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- Iron(III) complexes with meta-substituted bis(arylimino)pyridine ligands: Catalyst precursors for the selective oligomerization of ethylene
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Bis(arylimino)pyridine iron(III) complexes containing meta-halogen substituents at the iminophenyl rings were synthesized and characterized. In contrast to iron(II) complexes, the presence of at least one ortho-substituent at the iminophenyl rings is not obligative for catalytic activities of these iron(III) complexes. After activation with methylaluminoxane (MAO), these catalysts oligomerize ethylene to give also internal and branched olefins besides the expected linear α-olefins. The widths of the resulting molecular weight distributions and the degrees of isomerization of the resulting oligomers strongly depend on the substitution pattern at the ligand frameworks.
- G?rl, Christian,Beck, Nadine,Kleiber, Katharina,Alt, Helmut G.
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p. 110 - 127
(2012/02/02)
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- Studies of one-pot double couplings on dibromoquinolines
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In a series of studies, the regioselectivity of Suzuki couplings of dibromoquinolines has been investigated. In general, it is much harder to achieve high levels of regioselectivity in these systems compared to many of the other dibromoheteroaromatics that have been studied. Useful levels of selectivity could be achieved for both a 5,7-dibromoquinoline as well as 3,4-dibromoquinoline. Double Suzuki couplings could also be achieved on these two compounds.
- Piala, Alexander,Mayi, Diyar,Handy, Scott T.
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scheme or table
p. 4147 - 4154
(2011/07/08)
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- Toward optimization of the linker substructure common to transthyretin amyloidogenesis inhibitors using biochemical and structural studies
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To develop potent and highly selective transthyretin (TTR) amyloidogenesis inhibitors, it is useful to systematically optimize the three substructural elements that compose a typical TTR kinetic stabilizer: the two aryl rings and the linker joining them. Herein, we evaluated 40 bisaryl molecules based on 10 unique linker substructures to determine how these linkages influence inhibitor potency and selectivity. These linkers connect one unsubstituted aromatic ring to either a 3,5-X2 or a 3,5-X2-4-OH phenyl substructure (X = Br or CH3). Coconsideration of amyloid inhibition and ex vivo plasma TTR binding selectivity data reveal that direct connection of the two aryls or linkage through nonpolar E-olefin or -CH2CH2- substructures generates the most potent and selective TTR amyloidogenesis inhibitors exhibiting minimal undesirable binding to the thyroid hormone nuclear receptor or the COX-1 enzyme. Five high-resolution TTR·inhibitor crystal structures (1.4-1.8 A?) provide insight into why such linkers afford inhibitors with greater potency and selectivity.
- Johnson, Steven M.,Connelly, Stephen,Wilson, Ian A.,Kelly, Jeffery W.
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supporting information; experimental part
p. 6348 - 6358
(2009/12/03)
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- ANTIBACTERIAL COMPOSITIONS
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Compounds of formula (I) have antibacterial activity: wherein: m is 0 or 1 ; Q is hydrogen or cyclopropyl; AIk is an optionally substituted, divalent C1-C6 alkylene, alkenylene or alkynylene radical which may contain an ether (-O-), thioether (-S-) or amino (-NR)- link, wherein R is hydrogen, -CN or C1-C3 alkyl; X is -C(=O)NR6-, -S(O)NR6-, -C(=O)O- or -S(=O)O- wherein R6 is hydrogen, optionally substituted C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, -Cyc, or -( C1-C3 alkyl)-Cyc wherein Cyc is optionally substituted monocyclic carbocyclic or heterocyclic having 3-7 ring atoms; Z is N or CH, or CF; R2 and R3 are as defined in the description.
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- Convergent synthesis of platinum-acetylide dendrimers
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An efficient convergent route to the main chain type of organometallic dendrimers, in which platinum moieties are linked by 1,3,5-triethynylbenzene, has been developed. The synthesis of platinum-acetylide dendrons involved the use of two types of trialkylsilyl groups for protection of the terminal acetylene. The platinum-acetylide dendrimers were prepared up to the third generation by reacting dendrons with a triplatinum core and a tetraplatinum core. Spectroscopic characterization and trace experiments by gel permeation chromatography indicated that the dendrimer molecules have no structural defects. Although a π-conjugated system was used as the bridging ligand, electronic and fluorescence spectra suggested that the interaction among the platinum-acetylide moieties in the dendrimers was small.
- Onitsuka, Kiyotaka,Fujimoto, Masanori,Kitajima, Hotaka,Ohshiro, Nobuaki,Takei, Fumie,Takahashi, Shigetoshi
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p. 6433 - 6446
(2007/10/03)
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- Synthesis of Anthropomorphic Molecules: The NanoPutians
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Described here are the synthetic details en route to an array of 2-nm-tall anthropomorphic molecules in monomeric, dimeric, and polymeric form. These anthropomorphic figures are called, as a class, NanoPutians. Using tools of chemical synthesis, the ultimate in designed miniaturization can be attained while preparing the most widely recognized structures: those that resemble humans.
- Chanteau, Stephanie H.,Tour, James M.
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p. 8750 - 8766
(2007/10/03)
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- A modified Sandmeyer methodology and the synthesis of (±)-convolutamydine A
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(±)-Convolutamydine A (5) has been prepared by it concise synthesis from 3,5-dibromoaniline using a modified Sandmeyer methodology. The modified Sandmeyer methodology has also been found to be beneficial for the synthesis of other α-isonitrosoacetanilides. The 4,6-dibromohydroxyoxindole nucleus was further confirmed by comparison with the isomeric 5,7-dibromohydroxyoxindole.
- Garden, Simon J.,Torres, Jose C.,Ferreira, Alexandre A.,Silva, Rosangela B.,Pinto, Angelo C.
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p. 1501 - 1504
(2007/10/03)
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- SYNTHESIS OF 7-BROMO-5-IODO-4-OXO-1,4-DIHYDROQUINOLINE-2-CARBOXYLIC ACID
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The synthesis of 7-bromo-5-iodo-4-oxo-1,4-dihydroquinoline-2-carboxylic acid 7 is described.The synthesis was started from 2,6-dibromo-4-nitroaniline and carried out using a modified Conrad-Limpach procedure followed by a nucleophilic non-isotopic exchange.
- Dumont, Filip,Slegers, Guido
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p. 505 - 508
(2007/10/02)
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- Optionally substituted pyrido[2,3-d]pyridine-2,4(1H,3H)-diones and pyrido[2,]pyrimidine-2(1H,3H)-ones
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The present invention relates to optionally substituted pyrido[2,3-d]pyrimidine-2,4(1H,3H)-diones or optionally substituted pyrido[2,3-d]pyrimidine-2(1H,3H)-ones, i.e., compounds of Formula I: STR1 wherein: Y is --CH2 -- or --C(O)--; R1 is hydrogen or --(CH2)n --R7, wherein: R7 is aryl or heteroaryl, and n is 1 or 2, provided that when Y is --C(O)--, R7 is heteroaryl; and R2, R3, R4, R5 and R6 are hydrogen, or one is selected from lower alkyl, halo, carboxy, methoxycarbonyl, carbamoyl, methylcarbamoyl, di-methylcarbamoyl, methylcarbonyl, methylthio, methylsulfinyl, methylsulfonyl, hydroxymethyl, amino, trifluoromethyl, cyano or nitro; or R2, R3, R4 and R5 are independently selected from hydrogen, lower alkyl, nitro, chloro, fluoro, methoxycarbonyl or methylcarbonyl, provided at least one is hydrogen, and R6 is hydrogen; or a pharmaceutically acceptable ester, ether or salt thereof.
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- Magnetic susceptibilities of organic compounds: Part V - Influence of substituents on diamagnetic susceptibilities of disubstituted and trisubstituted benzenes
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The magnetic susceptibilities of a number of triads of isomeric disubstituted benzenes have been determined, choosing the compounds in such a way that the substituents are present in the following combinations: (i) two electron-releasing substituents, (ii) a halogeno and an electron-releasing substituent, (iii) a halogeno and an electron-attracting substituent, and (iv) two halogeno substituents.The data show that for types (i), (ii) and (iv), the ortho isomers have the highest magnetic susceptibilities, the susceptibilities decreasing in the order: ortho > meta > para; for type (iii), the meta-isomers have the highest susceptibilities, the susceptibilities decreasing in the order: meta > para > ortho.The diamagnetic susceptibilities of some isomeric trisubstituted benzenes have also been determined and the data reveal that the susceptibility is the highest where the crowding of substituents is the highest (1,2,3-isomer) and lowest where the substituents are staggered and least crowded (1,3,5-isomer).Another observation made in the case of trisubstituted benzene is the applicability of a principle of additivity of their diamagnetic susceptibilities.
- Baliah, V.,Jeyanthy, J. Judith Diana
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p. 472 - 476
(2007/10/02)
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- Antimicrobial composition and method containing N-(3,5-dihalophenyl)-imide compounds
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Novel N-(3,5-dihalophenyl)imide compounds, which exhibit a strong antimicrobial activity against microorganisms including phytopathogenic fungi, parasites of industrial products and pathogenic microorganisms, represented by the formula, STR1 wherein X and X' each represent halogens and A represents a substituted ethylene such as chloroethylene, C1 - C4 alkylthioethylene, C1 - C2 alkyl-ethylene or 1,2-di-C1 - C2 -alkyl-ethylene, a cyclopropylene such as 1,3-dimethylcyclopropylene, trimethylene, a cyclohexylene-1,2-, cyclohexenylene-1,2-, cyclohexadienylene-1,2- or o-phenylene. The N-(3,5-dihalophenyl)imide compounds can be obtained by any of methods which produce imide compounds or reaction of an N-(3,5-dihalophenyl)maleimide compound with a mercaptan, a hydrogen halide, phosphorus chloride or thionylchloride.
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