- Zinc(ii) and cadmium(ii) amorphous metal-organic frameworks (aMOFs): Study of activation process and high-pressure adsorption of greenhouse gases
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Two novel amorphous metal-organic frameworks (aMOFs) with chemical composition {[Zn2(MTA)]·4H2O·3DMF}n (UPJS-13) and {[Cd2(MTA)]·5H2O·4DMF}n (UPJS-14) built from Zn(ii) and Cd(ii) ions and extended tetrahedral tetraazo-tetracarboxylic acid (H4MTA) as a linker were prepared and characterised. Nitrogen adsorption measurements were performed on as-synthesized (AS), ethanol exchanged (EX) and freeze-dried (FD) materials at different activation temperatures of 60, 80, 100, 120, 150 and 200 °C to obtain the best textural properties. The largest surface areas of 830 m2 g-1 for UPJS-13 (FD) and 1057 m2 g-1 for UPJS-14 (FD) were calculated from the nitrogen adsorption isotherms for freeze-dried materials activated at mild activation temperature (80 °C). Subsequently, the prepared compounds were tested as adsorbents of greenhouse gases, carbon dioxide and methane, measured at high pressures. The maximal adsorption capacities were 30.01 wt% CO2 and 4.84 wt% CH4 for UPJS-13 (FD) and 24.56 wt% CO2 and 6.38 wt% CH4 for UPJS-14 (FD) at 20 bar and 30 °C.
- Almá?i, Miroslav,Bourrelly, Sandrine,Király, Nikolas,Vilková, Mária,Zeleňák, Vladimír
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p. 20137 - 20150
(2021/06/28)
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- Rigid Multidimensional Alkoxyamines: A Versatile Building Block Library
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Since the discovery of the “living” free-radical polymerization, alkoxyamines were widely used in nitroxide-mediated polymerization (NMP). Most of the known alkoxyamines bear just one functionality with only a few exceptions bearing two or more alkoxyamine units. Herein, we present a library of novel multidimensional alkoxyamines based on commercially available, rigid, aromatic core structures. A versatile approach allows the introduction of different sidechains which have an impact on the steric hindrance and dissociation behavior of the alkoxyamines. The reaction to the alkoxyamines was optimized by implementing a mild and reliable procedure to give all target compounds in high yields. Utilization of biphenyl, p-terphenyl, 1,3,5-triphenylbenzene, tetraphenylethylene, and tetraphenyl-methane results in linear, trigonal, square planar, and tetrahedral shaped alkoxyamines. These building blocks are useful initiators for multifold NMP leading to star-shaped polymers or as a linker for the nitroxide exchange reaction (NER), to obtain dynamic frameworks with a tunable crosslinking degree and self-healing abilities.
- Matt, Yannick,Wessely, Isabelle,Gramespacher, Lisa,Tsotsalas, Manuel,Br?se, Stefan
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supporting information
p. 239 - 245
(2020/12/17)
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- Preparation of Recyclable and Versatile Porous Poly(aryl thioether)s by Reversible Pd-Catalyzed C–S/C–S Metathesis
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Porous organic materials (polymers and COFs) have shown a number of promising properties; however, the lability of their linkages often limits their robustness and can hamper downstream industrial application. Inspired by the outstanding chemical, mechanical, and thermal resistance of the 1D polymer poly(phenylene sulfide) (PPS), we have designed a new family of porous poly(aryl thioether)s, synthesized via a mild Pd-catalyzed C–S/C–S metathesis-based method, that merges the attractive features common to porous polymers and PPS in a single material. In addition, the method is highly modular, allowing to easily introduce application-oriented functionalities in the materials for a series of environmentally relevant applications including metal capture, metal sensing, and heterogeneous catalysis. Moreover, despite their extreme chemical resistance, the polymers can be easily recycled to recover the original monomers, offering an attractive perspective for their sustainable use. In a broader context, these results clearly demonstrate the untapped potential of emerging single-bond metathesis reactions in the preparation of new, recyclable materials.
- Morandi, Bill,Rivero-Crespo, Miguel A.,Toupalas, Georgios
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supporting information
p. 21331 - 21339
(2021/12/17)
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- Remarkable Structural Diversity between Zr/Hf and Rare-Earth MOFs via Ligand Functionalization and the Discovery of Unique (4, 8)-c and (4, 12)-connected Frameworks
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Ligand modification in MOFs provides great opportunities not only for the development of functional materials with new or enhanced properties but also for the discovery of novel structures. We report here that a sulfone-functionalized tetrahedral carboxylate-based ligand is capable of directing the formation of new and fascinating MOFs when combined with Zr4+/Hf4+ and rare-earth metal cations (RE) with improved gas-sorption properties. In particular, the resulting M-flu-SO2 (M: Zr, Hf) materials display a new type of the augmented flu-a net, which is different as compared to the flu-a framework formed by the nonfunctionalized tetrahedral ligand. In terms of properties, a remarkable increase in the CO2 uptake is observed that reaches 76.6% and 61.6% at 273 and 298 K and 1 bar, respectively. When combined with REs, the sulfone-modified linker affords novel MOFs, RE-hpt-MOF-1 (RE: Y3+, Ho3+, Er3+), which displays a fascinating (4, 12)-coordinated hpt net, based on nonanuclear [RE9(μ3-?)2(μ3-??-)12(-COO)12] clusters that serve as hexagonal prismatic building blocks. In the absence of the sulfone groups, we discovered that the tetrahedral linker directs the formation of new RE-MOFs, RE-ken-MOF-1 (RE: Y3+, Ho3+, Er3+, Yb3+), that display an unprecedented (4, 8)-coordinated ken net based on nonanuclear RE9-clusters, to serve as bicapped trigonal prismatic building units. Successful activation of the representative member Y-ken-MOF-1 reveals a high BET surface area and total pore volume reaching 2621 m2 g-1 and 0.95 cm3 g-1, respectively. These values are the highest among all RE MOFs based on nonanuclear clusters and some of the highest in the entire RE family of MOFs. The present work uncovers a unique structural diversity existing between Zr/Hf and RE-based MOFs that demonstrates the crucial role of linker design. In addition, the discovery of the new RE-hpt-MOF-1 and RE-ken-MOF-1 families of MOFs highlights the great opportunities existing in RE-MOFs in terms of structural diversity that could lead to novel materials with new properties.
- Angeli, Giasemi K.,Batzavali, Danai,Mavronasou, Katerina,Tsangarakis, Constantinos,Stuerzer, Tobias,Ott, Holger,Trikalitis, Pantelis N.
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supporting information
p. 15986 - 15994
(2020/10/18)
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- All-Carbon-Linked Continuous Three-Dimensional Porous Aromatic Framework Films with Nanometer-Precise Controllable Thickness
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Inherently porous materials that are chemically and structurally robust are challenging to construct. Conventionally, dynamic chemistry is thought to be needed for the formation of uniform porous organic frameworks, but dynamic bonds can limit the stability of these materials. For this reason, all-carbon-linked frameworks are expected to exhibit higher stability performance than more traditional porous frameworks. However, the limited reversibility of carbon-carbon bond-forming reactions has restricted the exploration of these materials. In particular, the challenges associated with producing uniform thin films of all-carbon-linked frameworks has inhibited the study of these materials in applications where well-defined films are required. Here, we synthesize continuous and homogeneous films of two different all-carbon-linked three-dimensional porous aromatic frameworks with nanometer-precision thickness (PAF-1 and BCMP-2). This was accomplished by kinetically promoting surface reactivity while suppressing homogeneous nucleation. Through connection of the PAF film to a gold substrate via a self-assembled monolayer and use of flow conditions to continually introduce monomers, smooth and continuous PAF films can be grown with controlled thickness. This strategy allows traditional transition metal mediated carbon-carbon cross-coupling reactions to form porous, organic thin films. We expect that the chemical principles uncovered in this study will enable the synthesis of a variety of chemically and structurally diverse carbon-carbon-linked frameworks as high-quality films, which are inaccessible by conventional methods.
- B?rjesson, Karl,Evans, Austin M.,Ratsch, Martin,Yang, Yizhou,Ye, Chen,Zhang, Airui
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supporting information
p. 6548 - 6553
(2020/04/30)
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- Temperature Controls Guest Uptake and Release from Zn4L4 Tetrahedra
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We report the preparation of triazatruxene-faced tetrahedral cage 1, which exhibits two diastereomeric configurations (T1 and T2) that differ in the handedness of the ligand faces relative to that of the octahedrally coordinated metal centers. At lower temperatures, T1 is favored, whereas T2 predominates at higher temperatures. Host-guest studies show that T1 binds small aliphatic guests, whereas T2 binds larger aromatic molecules, with these changes in binding preference resulting from differences in cavity size and degree of enclosure. Thus, by a change in temperature the cage system can be triggered to eject one bound guest and take up another.
- Zhang, Dawei,Ronson, Tanya K.,Güryel, Songül,Thoburn, John D.,Wales, David J.,Nitschke, Jonathan R.
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supporting information
p. 14534 - 14538
(2019/10/11)
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- Molecular Vise Approach to Create Metal-Binding Sites in MOFs and Detection of Biomarkers
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We report a new approach to create metal-binding site in a series of metal–organic frameworks (MOFs), where tetratopic carboxylate linker, 4′,4′′,4′′′,4′′′′-methanetetrayltetrabiphenyl-4-carboxylic acid, is partially replaced by a tritopic carboxylate linker, tris(4-carboxybiphenyl)amine, in combination with monotopic linkers, formic acid, trifluoroacetic acid, benzoic acid, isonicotinic acid, 4-chlorobenzoic acid, and 4-nitrobenzoic acid, respectively. The distance between these paired-up linkers can be precisely controlled, ranging from 5.4 to 10.8 ?, where a variety of metals, Mg2+, Al3+, Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Ag+, Cd2+ and Pb2+, can be placed in. The distribution of these metal-binding sites across a single crystal is visualized by 3D tomography of laser scanning confocal microscopy with a resolution of 10 nm. The binding affinity between the metal and its binding-site in MOF can be varied in a large range (observed binding constants, Kobs from 1.56×102 to 1.70×104 L mol?1), in aqueous solution. The fluorescence of these crystals can be used to detect biomarkers, such as cysteine, homocysteine and glutathione, with ultrahigh sensitivity and without the interference of urine, through the dissociation of metal ions from their binding sites.
- Wang, Yang,Liu, Qi,Zhang, Qin,Peng, Bosi,Deng, Hexiang
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supporting information
p. 7120 - 7125
(2018/06/15)
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- Gold nanoparticles confined in imidazolium-based porous organic polymers to assemble a microfluidic reactor: Controllable growth and enhanced catalytic activity
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A synthetic strategy is developed to grow Au nanoparticles supported by imidazolium-based porous organic polymers (Au/IM-POPs) along the inner surface of a fused-silica microfluidic capillary. The thickness of the hybrid Au/IM-POP material layers can be tuned by changing the precursor concentration. A variety of imidazolium-based porous organic polymers are developed from tetrakis[4-(1-imidazolyl)phenyl]methane and bromo-functionalized linker molecules and fully characterized, which may be used to support Au nanoparticles. Additionally the IM-POPs and Au/IM-POPs show porosity and the ability to take up guest molecules. The capillary coated with Au/IM-POPs is further assembled to obtain a catalytic microfluidic reactor. The catalytic activity of Au nanoparticles supported by the porous imidazolium polymer is probed by using the reduction of nitrobenzene derivatives flowing through the microfluidic reactor. The catalytic microfluidic reactor demonstrates significantly enhanced turnover frequency magnitudes in comparison with the corresponding reactions under batch conditions.
- Fang, Haobin,Sun, Shujian,Liao, Peisen,Hu, Ya,Zhang, Jianyong
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supporting information
p. 2115 - 2121
(2018/02/09)
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- Azo-linked porous organic polymers: Robust and time-efficient synthesis: Via NaBH4-mediated reductive homocoupling on polynitro monomers and adsorption capacity towards aniline in water
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Time-efficient synthetic methods of porous organic polymers are searched in order to extend the applications of these materials. In this work, we show a robust and time-efficient synthetic method of azo-linked porous organic polymers named Azo-POPs based on a NaBH4-mediated reductive coupling polymerization on well-known polynitro monomers. Azo-POPs were found to have a high Brunauer-Emmett-Teller (BET) surface area and potential for aniline adsorption. Interestingly, Azo-POP-1 showed adsorption capacity towards aniline as high as 1059.68 mg g-1 at 293 K, which surpassed that of adsorbent materials reported in the literature.
- Zhou, Jin-Xiu,Luo, Xian-Sheng,Liu, Xiangxiang,Qiao, Yan,Wang, Pengfei,Mecerreyes, David,Bogliotti, Nicolas,Chen, Shi-Lu,Huang, Mu-Hua
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supporting information
p. 5608 - 5612
(2018/04/12)
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- Synthesis of tetraarylmethanes via a Friedel-Crafts cyclization/desulfurization strategy
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Tetraarylmethanes are an important class of molecules that contain four aryl groups bonded to a central carbon atom. The shape/three-dimensionality of these molecules makes them suitable for organic light-emitting diodes (OLEDs), organic solar cells, hydrogen storage, and even drug-delivery. Despite their importance, there are only a few methods available for their preparation. Herein, we report a simple procedure for the preparation of tetraarylmethanes that involves a bismuth-catalyzed Friedel-Crafts cyclization followed by a desulfurization reaction mediated by Raney nickel.
- Griffin, Paul J.,Fava, Matthew A.,Whittaker, St. John T.,Kolonko, Kristopher J.,Catino, Arthur J.
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p. 3999 - 4002
(2018/10/02)
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- Anhydrous proton conduction in porous organic networks
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Solid electrolyte separators within fuel cells enable efficient charge transport and prevent a mass bypass between the two half cells. Hydrated systems, like Nafion, reach unprecedented proton conductivities at ambient temperatures, but the demanding humidity management prevents their use beyond 80 °C, hence limiting the efficiency of current polymer-based systems. As such, water free and chemically inert, solid materials with excellent conductivities between 100 °C and 200 °C, are of high interest. A promising approach is the incorporation of heavier amphoteric molecules into micro- and mesoporous frameworks. Stronger host-guest interactions allow for higher temperatures, while still maintaining sufficient mobility and efficient transport pathways. Here, we present a systematic study investigating the influence of porosity, framework topology and dimensionality as well as framework functionality and charge carrier uptake on the proton conductivity for six porous organic networks (PONs) loaded with imidazole via gas phase adsorption. The resulting materials were thoroughly characterized by multinuclear NMR and IR spectroscopy and physisorption as well as powder X-ray diffraction and DSC experiments, revealing homogeneous distribution of the amphoteric guests within the pore structure. Electrochemical impedance spectroscopy up to 130 °C revealed remarkable conductivities of up to 10?3 S cm?1 under anhydrous conditions. We found 3D networks to favour high imidazole loading leading to high proton conductivities based on the Grotthuss mechanism. In contrast, 2D networks showed a lower guest molecule uptake and thus lower proton conductivities, which were governed by vehicle transport. Additional acid/base functionalities within the frameworks seem to have a negative effect on the proton conduction.
- Klumpen,Winterstein,Papastavrou,Senker
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supporting information
p. 21542 - 21549
(2018/11/20)
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- Two-Photon Absorption Properties and Structures of BODIPY and Its Dyad, Triad and Tetrad
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A series consisting of a dyad, a triad and a tetrad containing either two, three and four BODIPY units, respectively, has been synthesized and fully characterized and compared to two mono-BODIPY analogs (used as references). The one- and two-photon photophysical properties have been measured and the X-ray structures of four of the BODIPY derivatives have been determined. In the 700–900 nm range, the two-photon absorption (TPA) cross sections range from 30 GM to 160 GM for these compounds.
- Yang, Jian,Rousselin, Yoann,Bucher, Léo,Desbois, Nicolas,Bolze, Frédéric,Xu, Hai-Jun,Gros, Claude P.
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p. 838 - 844
(2018/10/05)
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- Divergent Synthesis of Porous Tetraphenylmethane Dendrimers
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Tetraphenylmethane-ethynylene-based shape-persistent dendrimers are a new class of nanoobjects with an intriguing 3D architecture. We report an efficient divergent strategy for their synthesis based on the Sonogashira Pd-catalyzed coupling of terminal alkynes with aryl iodides. As repeat unit, we prepared a tetraphenylmethane derivative bearing a terminal alkyne and three triazene moieties. Coupling of this building block to tetrakis(p-iodophenyl)methane afforded, after triazene activation, a dodecaiodo-terminated first generation dendrimer, which was transformed by another Sonogashira coupling into a methoxy-terminated second generation dendrimer with persistent globular shape and well-defined cavities. This work also unveils new aspects of triazene chemistry, i.e., the unprecedented efficient generation of an azo compound by mixing of a triazene with phenol.
- Urzúa, Julio I.,Torneiro, Mercedes
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p. 13231 - 13238
(2017/12/26)
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- Microporous organic polymers involving thiadiazolopyridine for high and selective uptake of greenhouse gases at low pressure
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A new core of [1,2,5]-thiadiazolo-[3,4-c]-pyridine was employed for the fabrication of microporous organic polymers exhibiting a very high CO2 uptake of 5.8 mmol g-1 (25.5 wt%) at 273 K and 1 bar. The presence of CO2-philic active sites and microporosity confer the high uptake and superior selectivity (61) towards CO2 over N2.
- Waseem Hussain, Md.,Bandyopadhyay, Sujoy,Patra, Abhijit
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supporting information
p. 10576 - 10579
(2017/09/29)
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- Water mediated proton conduction in a sulfonated microporous organic polymer
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Polymer membranes (PEMs) within fuel cells (FCs) act as separators and efficient proton conducting electrolytes. Established systems tend to microphase separation into hydrophilic and hydrophobic regions, making these materials prone to water loss at elevated temperatures. Therefore, recent approaches utilize porous materials, which promise stronger interactions between water molecules and the framework, while still providing efficient conductive pathways. Here we show, that the microporous polymer PAF-1 exhibits proton conductivities up to 10-1 S cm-1 under hydrous conditions, after post-synthetic sulfonation. Gas phase sulfonation turned out to be the essential step for introducing a sufficiently large amount of -SO3H groups and thus a high charge carrier concentration upon hydration. While the absolute conductivity of the sulfonated frameworks strongly depends on the water uptake, we found similar activation barriers for all relative humidities. Since water is homogeneously stored in micro- and mesoporous voids, the activation barrier of the interpore conductivity is decisive for the macroscopic properties.
- Klumpen,G?drich,Papastavrou,Senker
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supporting information
p. 7592 - 7595
(2017/07/12)
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- Microporous Organic Polyimides for CO2 and H2O Capture and Separation from CH4 and N2 Mixtures: Interplay between Porosity and Chemical Function
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Porous polyimides have been considered to be a promising material class for gas capture and sequestration, leading to the synthesis of a substantial number of individual networks with noteworthy sorption properties. In spite of these efforts, the vision of a chemical control of adsorption and desorption of small molecules, in particular, for the competing uptake of technical relevant gas mixtures, is still hardly investigated. Here, we present a systematic study of five new polyimide networks based on a set of linkers with chemical functionalities covering the full range from hydrophobic to hydrophilic interactions. The corresponding microporous organic polyimides (MOPI-I to -V) were synthesized successfully based on a condensation reaction between amino and anhydride linker molecules in m-cresol at high temperatures, resulting in cross-linking degrees beyond 95% in all cases. Argon and carbon dioxide isotherms reveal surface areas up to 940 m2/g with ultramicroporosity, about 50% microporosity and high thermal stabilities under air with decomposition temperatures up to 480 °C. Sorption screening for variable temperatures revealed remarkable uptakes for carbon dioxide up to 3.8 mmol/g and water vapor up to 19.5 mmol/g combined with a smooth gate opening around 0.25 p/p0 for MOPI-IV. In contrast, for MOPI-V the water vapor uptake decreases down to 7 mmol/g. Interestingly, the trend of the selectivities calculated by IAST and Henry does not correlate with the uptake behavior. For instance, MOPI-I and MOPI-III exhibit with 78 and 13 the highest CO2 over N2 and CH4 Henry selectivities, although their CO2 uptake is around 3.0 mmol/g. In total, we attribute the sorption properties for this class of materials mainly to the void size and shape within the ultramicroporous region. The chemical environment of the surfaces seems to have little influence on the uptake and a stronger effect on the separation behavior.
- Klumpen, Christoph,Breunig, Marion,Homburg, Thomas,Stock, Norbert,Senker, Juergen
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p. 5461 - 5470
(2016/08/19)
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- Electrochemically active porous organic polymers based on corannulene
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For the first time, porous organic polymers (POPs) based on the smallest buckybowl, corannulene (BB-POPs) have been synthesized. Three POPs were synthesised via Sonogashira co-polymerization of 1,2,5,6-tetrabromocorannulene and alkyne linkers. BB-POP-3 exhibits the highest surface area (SABET = 560 m2 g-1) and CO2 adsorption of 11.7 wt%, while they retain the redox properties of corannulene.
- Karunathilake, Arosha A.K.,Thompson, Christina M.,Perananthan, Sahila,Ferraris, John P.,Smaldone, Ronald A.
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supporting information
p. 12881 - 12884
(2016/11/06)
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- A novel 3D covalent organic framework membrane grown on a porous α-Al2O3 substrate under solvothermal conditions
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A novel approach to grow a 3D COF-320 membrane on a surface-modified porous α-Al2O3 substrate is developed. A compact and uniform COF-320 membrane with a layer thickness of ~4 μm is obtained. This is the first reported 3D COF functional membrane fabricated successfully on a common porous α-Al2O3 ceramic support. The gas permeation results indicate that the gas transport behavior is mainly governed by the predicted Knudsen diffusion process due to the large nanopores of 3D COF-320.
- Lu, Hui,Wang, Chang,Chen, Juanjuan,Ge, Rile,Leng, Wenguang,Dong, Bin,Huang, Jun,Gao, Yanan
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supporting information
p. 15562 - 15565
(2015/10/29)
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- Chiral porous organic frameworks for asymmetric heterogeneous catalysis and gas chromatographic separation
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Three chiral robust diene-based porous organic frameworks (POFs) are prepared. POF-1 is shown to be an efficient heterogeneous catalyst after metallation for asymmetric conjugation addition with up to 93% ee, and it can also function as a new chiral stationary phase for gas chromatographic separation of racemates. This journal is
- Dong, Jinqiao,Liu, Yan,Cui, Yong
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supporting information
p. 14949 - 14952
(2015/01/08)
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- Facile synthesis of azo-linked porous organic frameworks via reductive homocoupling for selective CO2 capture
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A facile Zn-induced reductive homocoupling reaction was used to synthesize azo-linked porous organic frameworks (azo-POFs) from easily accessed nitro monomers. Azo-POF-2 exhibits the highest CO2/N2 selectivity of 76 at 273 K among all self-coupled azo-linked porous polymers. This journal is the Partner Organisations 2014.
- Lu, Jingzhi,Zhang, Jian
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supporting information
p. 13831 - 13834
(2014/08/18)
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- Symmetry-guided synthesis of highly porous metal-organic frameworks with fluorite topology
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Two stable, non-interpenetrated MOFs, PCN-521 and PCN-523, were synthesized by a symmetry-guided strategy. Augmentation of the 4-connected nodes in the fluorite structure with a rigid tetrahedral ligand and substitution of the 8-connected nodes by the Zr/Hf clusters yielded MOFs with large octahedral interstitial cavities. They are the first examples of Zr/Hf MOFs with tetrahedral linkers. PCN-521 has the largest BET surface area (3411 m 2 g-1), pore size (20.5×20.5×37.4 A?) and void volume (78.5%) of MOFs formed from tetrahedral ligands. This work not only demonstrates a successful implementation of rational design of MOFs with desired topology, but also provides a systematic way of constructing non-interpenetrated MOFs with high porosity. Meet me at the symmetry gates: Using a symmetry-guided design strategy, two stable, non-interpenetrated MOFs, were synthesized by augmenting the fluorite topology with tetrahedral linkers, thus expanding the cavity size (see scheme) and giving the largest pore size of any MOF with tetrahedral ligands. Copyright
- Zhang, Muwei,Chen, Ying-Pin,Bosch, Mathieu,Gentle III, Thomas,Wang, Kecheng,Feng, Dawei,Wang, Zhiyong U.,Zhou, Hong-Cai
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supporting information
p. 815 - 818
(2014/01/23)
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- Dendrimer-type peptoid-decorated hexaphenylxylenes and tetraphenylmethanes: Synthesis and structure in solution and in the gas phase
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Branched organic nanostructures are useful scaffolds that find multiple applications in a variety of fields. Here, we present a novel approach to dendrimer-like structures. Our design contains a rigid hydrocarbon-based core (hexaphenylxylylene/tetraethynylphenylmethane) combined with a library of N-substituted oligoglycines (so-called peptoids) providing a flexible shell. The use of click chemistry allows rapid assembly of the nanostructures. The possibility of tuning the size and the solubility of this new type of nanostructure will be advantageous for future applications such as heterogeneous catalysis.
- Peschko, Katharina,Schade, Alexandra,Vollrath, Sidonie B.L.,Schwarz, Ulrike,Luy, Burkhard,Muhle-Goll, Claudia,Weis, Patrick,Br?se, Stefan
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p. 16273 - 16278
(2015/01/09)
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- Central-atom size effects on the methyl torsions of group XIV tetratolyls
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The Group XIV tetratolyl series X(C6H4-CH 3)4 (X=C, Si, Ge, Sn, Pb) were studied by using inelastic neutron scattering to measure the low-energy phonon spectra to directly access the methyl-group torsional modes. The effect of increased molecular radius as a function of the size of the central atom was shown to have direct influence on the methyl dynamics, reinforced with the findings of molecular dynamics and contact surface calculations, based upon the solid-state structures. The torsional modes in the lightest analogue were found to be predominantly intramolecular: the Si and Ge analogues have a high degree of intermolecular methyl-methyl group interactions, whilst the heaviest analogues (Sn and Pb) showed pronounced intermolecular methyl interactions with the whole phonon bath of the lattice modes. Size matters! The size of the central atom in the Group XIV tetratolyls was shown to determine the solid-state structures courtesy of the effect that it has on the overall size of the molecules (see figure). Because the outer-most methyl groups enter into close intermolecular interactions (for the Si and Ge analogues), the structure is driven to lower symmetry; as a consequence, the smallest (C) and largest (Sn and Pb) analogues are isostructural. Copyright
- Ng, Maggie C. C.,Harper, Jason B.,Stampfl, Anton P. J.,Kearley, Gordon J.,Rols, Stephane,Stride, John A.
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supporting information
p. 13018 - 13024
(2013/01/15)
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- Photocurable compound
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Disclosed is a compound having a photocurable urethane (meth)acrylate group, its manufacturing method, and a photocurable composition including the compound. The compound is represented by Chemical Formulae 1 to 6. Each of Chemical Formulae 1 to 6 includes a urethane (meth)acrylate group represented by Chemical Formula 1-1 or 1-2.
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Page/Page column 19-20
(2012/07/27)
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- Cross coupling reactions of multiple CCl bonds of polychlorinated solvents with Grignard reagent using a pincer nickel complex
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The nickel(II) complex of a bulky pincer-type ligand, N,N′-bis(2,6- diisopropylphenyl)-2,6-pyridinedicarboxamido, was examined for sp 3-sp3 coupling of Grignard reagents with polychlorinated solvents. The nickel(II) complex catalyzed CC coupling of polychlorinated alkyl halides, such as dichloromethane (CH2Cl2), chloroform (CHCl3), and carbon tetrachloride (CCl4), with various Grignard reagents. The effective activation of multiple CCl bonds proceeded under ambient reaction conditions and within a short time (20 min). This catalyst displays the highest activity yet reported for this reaction type, with catalyst loading as low as 0.4 mol% and turnover frequency (TOF) as high as 724 h-1. The catalyst is capable of replacing all chlorine atoms with CC bond formations for all of the polychlorinated solvents under investigation. The catalytic process could prove to be an efficient method of remediation of toxic polychlorinated solvents while generating synthetically and commercially important chemicals.
- Gartia, Yashraj,Nasini, Udaya Bhasker,Ghosh, Anindya,Biswas, Abhijit,Stadler, Matthew
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p. 322 - 327,6
(2020/07/30)
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- Allylnickel(II) and allylpalladium(II) derivatives of [(2- (diphenylphosphino)ethyl)cyclopentadienyl]tricarbonylmetalates: Reactions with free radicals
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The emerging utility of the bridging (2-(diphenylphosphino)ethyl) cyclopentadienyl (CpPPh) ligand to kinetically stabilize early-late metal-metal bonds to facilitate novel reactions in heterobimetallics is further established by the syntheses of four-legged piano stool M′{M(η 3-L)}(CO)3(μ-η5:η1- CpPPh) (M′ = Cr, Mo, W; M = Ni, Pd; L = allyl, 2-methylallyl, cyclohexenyl). Complexes 1-3 (M = Ni, L = allyl) and 4-6 (M = Ni, L = 2-methylallyl) are the first structurally characterized heterobimetallics with transition metal-Ni(η3-allyl) units, while 7-9 (M = Ni, L = cyclohexenyl) are the only structurally characterized transition metal-Ni(η3-cyclohexenyl) complexes. Like Pd(η3- allyl)Cl(PPh3), 1-3 and 10-12 (M = Pd, L = allyl) respectively provide 4,4,4-triphenyl-1-butene as the sole allyl ligand coupling product from competitive reactions of phenyl and trityl radicals. However, while phenyl radical attack at the Pd(II) of Pd(η3-allyl)Cl(PPh3) is proposed as the first step in the trityl radical-allyl ligand coupling reaction, direct trityl radical attack at η3-allyl is strongly suggested in 1-3 and 10-12, respectively. A modest heterobimetallic effect may render the chromium complexes 1 and 10 more reactive with trityl radical than the tungsten complexes 3 and 12.
- Fischer, Paul J.,Neary, Michelle C.,Heerboth, Aaron P.,Sullivan, Kevin P.
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experimental part
p. 4562 - 4568
(2011/01/07)
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- A novel perylene diimide-based tetrahedral molecule: Synthesis, characterization and self-assembly with gold nanoparticles
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In this study, a novel tetrahedral molecule TPPY was successfully designed and synthesized. The self-assembly of TPPY with gold nanoparticles (Au NPs) in toluene has also been investigated. The aggregation morphologies of Au NPs can be controlled to produce different aggregate structures by changing the concentration of ligand TPPY. Indian Academy of Sciences.
- Li, Jun-Bo,Yu, Xiang-Lin,Fu, Jing,Liu, Xiwen,Zeng, Yang
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scheme or table
p. 839 - 846
(2011/10/04)
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- The central atom size effect on the structure of group 14 tetratolyls
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The tetraphenyl derivatives of the Group 14 elements are of great potential interest as supramolecular constructs in extended porous networks. The tetratolyl Group 14 compounds were synthesized by using a general reaction scheme involving the nucleophilic addition of an organometallic reagent to the electrophilic center of the Group 14 element. The tetrachloride derivatives were used for the synthesis of the silane, germane and stannane compounds. Sn(Tol)4 was found to have tunnel splittings much smaller than the minimum line width available on IN16, whereas the lighter analogues displayed a remarkable size effect of the central atom. The tunneling peaks were observed to persist up to around 30 K, before softening and extending into the limit of quasielastic diffusion in which the rotors undergo thermally excited rotation.
- Ng, Maggie C. C.,Craig, Donald J.,Harper, Jason B.,Van-Eijck, Lambert,Stride, John A.
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supporting information; experimental part
p. 6569 - 6572
(2010/02/28)
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- Four-fold click reactions: Generation of tetrahedral methane- and adamantane-based building blocks for higher-order molecular assemblies
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A modular concept for the generation of achiral and chiral non-racemic tetrahedral tectons from common precursors was developed. The tectons presented here are based on tetraphenylmethane or 1,3,5,7-tetraphenyladamantane core structures. They are obtained through high-yielding four-fold click reactions, using either the tetraazido or the tetraalkyne precursors. In most cases, the tetratriazoles are obtained as pure products after simple washing with water and methanol. The side chains of the tectons prepared include a self-complementary DNA dimer, obtained from a 3′-azidonucleoside and a phosphoramidite. The concept allows for a variation of the "sticky ends", leading to tecton or ligand libraries.
- Plietzsch, Oliver,Schilling, Christine Inge,Tolev, Mariyan,Nieger, Martin,Richert, Clemens,Muller, Thierry,Braese, Stefan
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supporting information; experimental part
p. 4734 - 4743
(2009/12/08)
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- Preparation of functionalised tetraphenylmethane derivatives via the Suzuki-Miyaura cross-coupling reaction
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A general methodology for the synthesis of various symmetrical and unsymmetrical tetraphenylmethane (TPM) derivatives is reported using the Suzuki-Miyaura (SM) cross-coupling reaction as a key step. The formation of an interesting self-coupling product 14 during the SM cross-coupling reaction of mono-iodo tetraphenylmethane derivative 5 is also observed.
- Kotha, Sambasivarao,Behera, Manoranjan
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p. 2684 - 2689
(2007/10/03)
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- Tetrahedral n-type materials: Efficient quenching of the excitation of p-type polymers in amorphous films
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Tetrahedral naphthalenediimide compound 1 has been synthesized as an example of a new class of amorphous n-type materials, in which the nondirectionality obtained by its shape is decoupled from its optoelectronic properties. 1 forms bicontinuous films with p-type polymers and effectively quenches the excited state, yielding long-lived mobile charge carriers on pulsed illumination. Copyright
- Ganesan, Palaniswamy,Yang, Xiaoniu,Loos, Joachim,Savenije, Tom J.,Abellon, Ruben D.,Zuilhof, Han,Sudhoelter, Ernst J. R.
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p. 14530 - 14531
(2007/10/03)
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- ALKYLATED TETRAKIS(TRIAMINOTRIAZINE) COMPOUNDS AND PHASE CHANGE INKS CONTAINING SAME
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Disclosed are compounds of the formulae 1wherein, provided that at least one of R1, R2, R3, R4, R5, and R6 is a hydrogen atom, and provided that at least one of R1, R2, R3, R4, R5, and R6 is not a hydrogen atom, R1, R2, R3, R4, R5, and R6 each, independently of the others, is (i) a hydrogen atom, (ii) an alkyl group, (iii) an aryl group, (iv) an arylalkyl group, or (v) an alkylaryl group. Also disclosed are phase change ink compositions comprising a colorant and a phase change ink carrier comprising a material of this formula.
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- Thermolysis of N-tetramethylpiperidinyl triphenylacetate: Homolytic fragmentation of a TEMPO ester
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Thermolysis of N-tetramethylpiperidinyl triphenylacetate (7, Ph 3CCO2T, T = 2,2,6,6-tetramethylpiperidinyl) in benzene at 146 °C leads to the formation of triphenylmethane (Ph3CH, 80%), tetramethylpiperidine (TH, 91%), and tetraphenylmethane (Ph4C, 9%). First-order rate constants for the decomposition at 132.8 and 150.0 °C were 2.20 × 10-6 and 2.88 × 10-5 s-1, respectively. In benzene-d6 solvent the triphenylmethane was formed as Ph3CD to the extent of 20%, as determined by 1H NMR and mass spectrometry. The results are interpreted as showing that Ph 3CCC2T undergoes thermolysis by concerted two-bond scission with formation of Ph3C., tetramethylpiperidinyl radicals and CO2. The formation of Ph4C occurs by addition of Ph3C. to benzene, followed by hydrogen atom abstraction from the resulting adduct. Calculations using DFT methods at the B3LYP/6-311++G** level were used to elucidate the bond fission of HCO2T (2), and indicate that cleavage to HCO2. and T. is favored by 7.8 kcal mol-1 relative to cleavage to HC(·)=O and TO., in agreement with the experimental results. Copyright
- Henry-Riyad, Huda,Tidwell, Thomas T.
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p. 559 - 563
(2007/10/03)
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- Convenient syntheses of tetraarylmethane starting materials
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Tetraphenylmethane (1) and several functionalized tetraphenylmethanes 4-7, all of them useful building blocks for the construction of tetraarylmethane frameworks, are readily synthesized by improved standard procedures in multigram quantities. The structure of compound 5 has been additionally corroborated by an X-ray structure analysis. The novel class of tetrakis(thiazolylphenyl)methanes 8 showing a significant blue emission upon UV-excitation can be prepared in good yield by Hantzsch synthesis starting from the tetra(α-bromoketone) derivative 4b.
- Zimmermann, Thomas J.,Mueller, Thomas J. J.
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p. 1157 - 1162
(2007/10/03)
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- Tetrastyrylmethane
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The first synthesis of tetrastyrylmethane is reported.
- Su, Dan,Menger
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p. 1485 - 1488
(2007/10/03)
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- Isonitriles as source and fate of imidoyl radicals: A novel homolytic α-fragmentation
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Imidoyl radicals 4a-c react with phenylacetylene to give annulation products and nitrile 12, arising from β-scission of the intermediate iminyl radical that is involved in the rearrangement of azaspirocyclohexadienyl 8. In contrast, imidoyls 4d and 15 do not react with the alkyne and give good yields of the corresponding isonitriles through a novel example of homolytic α-fragmentation.
- Nanni, Daniele,Pareschi, Patrizia,Tundo, Antonio
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p. 9337 - 9340
(2007/10/03)
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- Photoinduced Electron-Transfer Reaction of (Phenylazo)triphenylmethane(PAT). Behavior of Generated Trityl Cation
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The decomposition mechanism of photoinduced electron transfer (PET) between electron deficient sensitizers and (phenylazo)triphenylmethane (PAT) was investigated. In 9,10-dicyanoanthracene (DCA) sensitized reaction, benzene, triphenylmethane, 3,3,3-triphenylpropionitrile, and [4-(diphenylmethyl)phenyl]acetonitrile were obtained, and the product distribution was the same as for the direct photolysis and the thermolysis. In the case of 2,4,6-triphenylpyrylium tetrafluoroborate (TPP+) sensitization, the product distribution was drastically changed and 9-phenylfluorene was found to be one of the main products. The results of the irradiation wavelength effects indicate that 9-phenylfluorene is produced by the photoreaction of a trityl cation which is generated by the decomposition of a radical cation of PAT. The results of the experiments of laser flash photolysis suggest that the rate of back electron transfer between a radical anion of the sensitizer and a trityl cation plays an important role in these reactions.
- Miyagawa, Nobukazu,Karatsu, Takashi,Futami, Yasuo,Kunihiro, Takeshi,Kiyota, Atsushi,Kitamura, Akihide
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p. 3325 - 3329
(2007/10/03)
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- Efficient Catalysis of Hydrodediazoniations in Dimethylformamide
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For hydrodediazoniations (the replacement of a diazo group by hydrogen) in DMF, several substances act as catalysts through their ability to serve as electron donors and initiate free-radical reactions.A general procedure has been developed in which FeSO4 speeds the conversion and leads to higher yields.Trapping experiments demonstrated the presence of free-radical intermediates.N,N-Dimethylacetamide was found to rival DMF as a source of hydrogen atoms.
- Wassmundt, Frederick W.,Kiesman, William F.
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p. 1713 - 1719
(2007/10/02)
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- Environmentally Friendly Catalysis using Supported Reagents: Evolution of a Highly Active Form of Immobilised Aluminium Chloride
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An entirely heterogeneous form of aluminium chloride that is highly active in the liquid-phase alkylation of aromatics using alkenes and chloroalkanes is prepared by treating porous support materials with AlCl3 in solution.
- Clark, James H.,Martin, Keith,Teasdale, Andrew J.,Barlow, Simon J.
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p. 2037 - 2040
(2007/10/02)
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- Catalytic C-C bond formation using triorganothallium reagents
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The first catalytic system employing triorganothallium compounds in the formation of carbon-carbon bonds, is described.
- Marko,Kantam
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p. 2255 - 2258
(2007/10/02)
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- The Ambident Reactivity of Triphenylmethyl Radicals in Hydrogen-abstraction Reactions and the Mechanism of the Base-catalysed Rearrangement of (Diphenylmethylene)cyclohexadienes (a Type of Semibenzene) into Triphenylmethane
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Thermolysis of tri(phenyl)(phenylazo)methane (2) in non-deuteriated 2,2-dimethoxypropane in the presence of non-deuteriated sodium methoxide furnishes, among other products, mixtures of the deuteriated analogues of triphenylmethane (1c) and of deuteriated analogues of (p-biphenylyl)diphenylmethane (3a).The former was shown to be a mixture of the hexadecadeuterio derivative (6c) and the isomeric monoprotiopentadecadeuterio derivatives (6a and b), while the latter proved to be a mixture of the pentaprotio derivative (3d) and the isomeric hexaprotio derivatives (3b and c).The formation of compound (6b) proves the ambident reactivity of triphenylmethyl radicals in hydrogen-abstraction reactions, while the observed ratio of compounds (6a and b) indicates the rearrangements of the intermediate semibenzenes (7) and (8) to be multistep conducted-tour rearrangements (Scheme 1).
- Huszthy, Peter,Lempert, Karoly,Simig, Gyula,Tamas, Jozsef,Hegedus-Vajda, Judit,Toth, Gabor
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p. 491 - 498
(2007/10/02)
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- Pentavalent Organobismuth Reagents. Part 3. Phenylation of Enols and of Enolate and other Anions
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The phenylation of enols and of enolate anions of ketones, β-diketones and keto esters has been studied using a range of Bi reagents.Under basic conditions C-phenylation is observed and, even hindered, perphenylated compounds are easily synthesized.Under neutral and acidic conditions ordinary ketones do not react and enolic systems give O-phenylation.A number of other anions have been phenylated under basic conditions, including the key compound indole wich mainly gave 3-C-phenylation.All these reactions can be supposed to have one of two alternative mechanisms, which parallel the two mechanisms proposed for the phenylation of phenols.
- Barton, Derek H. R.,Blazejewski, Jean-Claude,Charpiot, Brigitte,Finet, Jean-Pierre,Motherwell, William B.,et al.
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p. 2667 - 2676
(2007/10/02)
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- Reaction of Arenesulphonyl Halides with Free Radicals. Part 2
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The generation of arenesulphonyl radicals by halogen abstraction from arenesulphonyl bromides and iodides is described.The relative reactivities of halogen abstraction by phenyl, 1-cyano-1-methylethyl, and benzyl radicals in benzene solution at 60 deg C are reported.These relative reactivities are almost independent of the nature of the substituents on the benzene ring of ArSO2Br.Sulphonyl iodides are more reactive towards phenyl radicals than bromides which in turn are more reactive than the corresponding chlorides (relative reactivities 602:192:1).
- Correa, Carlos M. M. da Silva,Oliveira, Maria Augusta B. C. S.
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p. 711 - 716
(2007/10/02)
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- Carbanion Photochemistry. 7. The SRN1 vs. SET Photoarylation of Triphenylmethyl Anion
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Irradiation of (triphenylmethyl)lithium in tetrahydrofuran containing bromobenzene, iodobenzene, or diphenyl sulfoxide produced three major products: tetraphenylmethane (TPM), biphenylyldiphenylmethane (BDM), and 2-(triphenylmethyl)tetrahydrofuran (TTF).The product composition was a function of anion and acceptor concentration and reflected the competition among solvent, triphenylmethyl anion, and triphenylmethyl radical.Product composition studies thus provide detailed information about the key steps in the mechanism.
- Tolbert, Laren M.,Martone, Daniel P.
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p. 1185 - 1190
(2007/10/02)
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- Efficient Coupling of Tertiary Alkyl Halides with Dialkylzinc and Titanium Compounds
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Dialkylzinc compounds react with tertiary halides to afford the corresponding coupling products containing a quaternary carbon atom, thereby making geminal dialkylation of ketones or hydroalkylation of olefins possible.
- Reetz, Manfred T.,Wenderoth, Bernd,Peter, Roland,Steinbach, Rainer,Westermann, Juergen
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p. 1202 - 1204
(2007/10/02)
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