- IODINE(III)-MEDIATED RADIOFLUORINATION
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A process for fluorination of aromatic compounds employing iodonium ylides and applicable to radiofluorination using 18F is described. Processes, intermediates, reagents and radiolabelled compounds are described.
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- Rational Design and Synthesis of a Highly Porous Copper-Based Interpenetrated Metal-Organic Framework for High CO2 and H2 Adsorption
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Interpenetrated metal-organic frameworks (MOFs) are often observed to show lower porosity than their non-interpenetrating analogues. It would be highly desirable if the interpenetrated MOFs could still provide high stability, high rigidity, and optimal pore size for applications. In this work, an asymmetrical tricarboxylate organic linker was rationally designed for the construction of a copper(II)-based microporous MOF with a twofold interpenetrated structure of Pt3O4 topology. In spite of having structural interpenetration, the activated MOF shows high porosity with a Brunauer-Emmett-Teller surface area of 2297 m2g-1, and high CO2 (15.7 wt% 273 K and 1 bar) and H2 uptake (1.64 wt% 77 K and 1 bar). Playing with symmetry: A C2-symmetric tricarboxylate organic linker with elongated arms has been developed for the construction of a twofold interpenetrated metal-organic framework. Despite its structural interpenetration, the framework exhibits high surface area and high adsorption capability for CO2 and H2 (1.64 wt% at 77 K and 1 bar).
- Bose, Purnandhu,Bai, Linyi,Ganguly, Rakhesh,Zou, Ruqiang,Zhao, Yanli
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p. 1259 - 1266
(2015/08/11)
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- Chiral oxazoline substituted optically active poly(m-phenylene)s: Synthesis and coupling polymerizations of (S)-4-benzyl-2-(3,5-dihalidephenyl) oxazoline using transition metal catalysts
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Optically active poly(m-phenylene)s substituted with chiral oxazoline derivatives have been synthesized by the nickel-catalyzed Yamamoto coupling reaction of optically active (S)-4-benzyl-2-(3,5-dihalidephenyl)oxazoline derivatives (X = Br or I). The structures and chiroptical properties of the polymers were characterized by spectroscopic methods and thermal gravimetric analyses. The polymers showed higher absolute optical specific rotation values than their corresponding monomer, and showed a Cotton effect at transition region of conjugated main chain. The optical activities of the polymers should be attributed to the higher order structure such as helical conformations. Moreover, the helical conformation could be induced by addition of metal salts into polymer solutions. The polymers showed good thermal stabilities, which was attributable to the oxazoline side chains.
- Rattanatraicharoen, Poompat,Tanaka, Yoko,Shintaku, Keiko,Kawaguchi, Takuro,Yamabuki, Kazuhiro,Oishi, Tsutomu,Onimura, Kenjiro
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p. 1315 - 1322
(2013/04/10)
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- Optically active, amphiphilic poly(meta -phenylene ethynylene)s: Synthesis, hydrogen-bonding enforced helix stability, and direct AFM observation of their helical structures
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Optically active, amphiphilic poly(meta-phenylene ethynylene)s (PPEa) bearing l- or d-alanine-derived oligo(ethylene glycol) side chains connected to the backbone via amide linkages were prepared by microwave-assisted polycondensation. PPEa's exhibited an intense Cotton effect in the π-conjugated main-chain chromophore regions in various polar and nonpolar organic solvents due to a predominantly one-handed helical conformation stabilized by an intramolecular hydrogen-bonding network between the amide groups of the pendants. The stable helical structure was retained in the bulk and led to supramolecular column formation from stacked helices in oriented polymer films as evidenced by X-ray diffraction. Atomic force microscopy was used to directly visualize the helical structures of the polymers in two-dimensional crystalline layers with molecular resolution, and, for the first time, their absolute helical senses could unambiguously be determined.
- Banno, Motonori,Yamaguchi, Tomoko,Nagai, Kanji,Kaiser, Christian,Hecht, Stefan,Yashima, Eiji
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supporting information; experimental part
p. 8718 - 8728
(2012/06/30)
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- A rigid metallohexameric macrocycle composed of endo- and exo-cyclic bisterpyridine-metal complexes
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Synthesis of terpyridine-based building blocks has allowed the self-assembly of a nanosized metallomacrocycle with precisely positioned, peripheral metal complexes. Construction of the precursors included the assembly of a heteroleptic bisterpyridine-Ru(ii) complex possessing a diiodoaryl moiety that was subsequently reacted with two equivalents of 4′-ethynyl-2, 2′:6′,2′′-terpyridine via a Pd(0)-catalyzed Sonagashira coupling, to generate the requisite monomer with two, 120°-juxtaposed metal coordination sites. Addition of one equivalent of Fe(ii) to one equivalent of the bisligand afforded the metallocycle with 12 metals [6 internal Fe(ii) ions and 6 external Ru(ii) ions] measuring ca. 7 nm in diameter.
- Li, Sinan,Moorefield, Charles N.,Shreiner, Carol D.,Wang, Pingshan,Sarkar, Rajarshi,Newkome, George R.
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experimental part
p. 2130 - 2135
(2011/11/13)
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- H-Bonding-driven gel formation of a phenylacetylene macrocycle
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An amide-containing phenylacetylene macrocycle (PAM) has been synthesized and its gelation properties were studied in different solvents. Surprisingly, this macrocycle forms organogels at low concentration in many polar and apolar solvents. XRD and FTIR analysis suggest that this macrocycle forms stable supramolecular assemblies owing to H-bonding. Scanning electron microscopy analyses show the formation of bundles of nanofibrils, demonstrating the long-range organization of this material.
- Cantin, Katy,Rondeau-Gagne, Simon,Neabo, Jules Romeo,Daigle, Maxime,Morin, Jean-Francois
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supporting information; experimental part
p. 4440 - 4443
(2011/07/30)
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- Carbazole-based hole transport and/or electron blocking materials and/or host polymer materials
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This invention relates generally to norbornene-monomer, poly(norbornene)homopolymer, and poly(norbornene)copolymer compounds containing a functionalized carbazole side chain, having desirable solution processability and host characteristics. It also relates to hole transport and/or electron blocking materials, and to organic host materials for an organic luminescence layer, an OLED device, and compositions of matter which include these compounds.
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- CARBAZOLE-BASED HOLE TRANSPORT AND /OR ELECTRON BLOCKING MATERIALS AND /OR HOST POLYMER MATERIALS
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This invention relates generally y to norbornene -monomer, poly (norbornene) homopolymer, and poly (norbornene) copolymer compounds containing a functionalized carbazole side chain, having desirable solution processability and host characteristics. It also relates to hole transport and/or electron blocking materials, and to organic host materials for an organic luminescence layer, an OLED device, and compositions of matter which include these compounds.
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Page/Page column 57-58
(2009/07/25)
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- Microwave-accelerated synthesis of lengthy and defect-free poly(m-phenyleneethynylene)s via AB′ and A2 + BB′ polycondensation routes
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A novel microwave-assisted polycondensation protocol involving an in-situ activation/coupling scheme has been developed and applied to the preparation of lengthy poly(m-phenyleneethynylene)s without diyne defects via either AB′ or A2 + BB′ approaches.
- Khan, Anzar,Hecht, Stefan
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p. 300 - 301
(2007/10/03)
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- Dirhodium(II) tetrakis(perfluoroalkylbenzoates) as partially recyclable catalysts for carbene transfer reactions with diazoacetates
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Three highly fluorinated dirhodium(II) tetrakis(benzoates), [Rh2(O2CRF)4, RF=C6H4-4-C6F13 (3) and C6H3-3,5-di(CnF2n+1) (n=6: 4; n=8: 5)], have been prepared and characterized. Only 4 and 5 are suited for applications in fluorous synthesis due to their excellent solubility in fluorous solvents. They were found to catalyze the following carbenoid reactions of diazo compounds in the fluorous solvents 1,1,2-trichloro-1,2,2-trifluoroethane and perfluoro(methylcyclohexane): cyclopropanation of styrenes using methyl diazoacetate, intermolecular carbene C-H insertion into hexane with methyl diazoacetate, and intramolecular aromatic C-H insertion of an α-diazo-β-ketoester. Except for the second reaction type, the catalyst could be recovered to a high extent by a liquid-liquid extraction (fluorous solvent - dichloromethane) due to its preference for the fluorous solvent. For the cyclopropanation reactions, the recovered catalyst was used in four subsequent reaction/workup cycles without significant loss of activity. In contrast, the catalyst could not be recovered from the carbenoid C-H insertion reaction with hexane; apparently, some by-products of this sluggish reaction, such as carbene dimers and oligomers, caused the deactivation or destruction of the catalyst.
- Endres, Andreas,Maas, Gerhard
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p. 3999 - 4005
(2007/10/03)
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- A strategy for the assembly of multiple porphyrin arrays based on the coordination chemistry of Ru-centered porphyrin pentamers
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An approach which employs pentameric porphyrin arrays as building blocks toward larger porphyrin arrays is described. Two flexible, and one relatively rigid, Ru-centered porphyrin pentamers (1-3) were synthesized and fully characterized. Their potential as building blocks toward larger porphyrin arrays has been studied via their coordination chemistry using bidentate and tetradentate ligands. DABCO (diazabicyclo[2.2.2]octane) can bind two monomeric porphyrins but was found to be too small to allow the complete formation of a 10-porphyrin array. On the other hand, titration of a larger bridging dipyridyl porphyrin ligand 17 (0.5 equiv) with 1 or 2 and tetrapyridyl ligand 18 (0.25 equiv) with 3 results in the formation of the 11-porphyrin and 21-porphyrin arrays, respectively, with the 21-porphyrin array containing porphyrins in three different metalation states. Changes in the chemical shift of the inner NH protons as well as the ortho- and meso-protons of the pyridyl groups of the porphyrin ligand clearly indicate the formation of large multiple porphyrin complexes. These studies demonstrate that by use of carefully designed building blocks and suitable bridging ligands, porphyrin arrays can be constructed with a dramatic increase in size in relatively few steps. Exploiting the fact that the strength of binding of pyridyl ligands is Ru > Zn > Ni, intra- vs intermolecular competition has been used to investigate aspects of the folding of the array. The photophysical properties of 3 are also described.
- Mak,Bampos,Darling,Montalti,Prodi,Sanders
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p. 4476 - 4486
(2007/10/03)
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- The direct iodination of arenes with chromium(VI) oxide as the oxidant
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An easy and cheap laboratory method is presented for the direct mono- and diiodination of a number of activated and deactivated arenes. The main iodination reactions occurred at the temperatures not exceeding 65°C for 0.5-12 h in the anhydrous, strongly acidic liquid system, I2/AcOH/Ac2O/H2SO4, in the presence of prior dissolved CrO3 used as the oxidant. The yields of the pure iodinated products varied from 31% (for 3,5- diiodobenzoic acid) up to 90% (for 4-iodoanisole). So far, benzonitrile and some oxidizable aromatics, e.g. naphthalene, fluorene, xanthene, and thiophene, have been found to be unsuitable for the effective iodination. Nevertheless, this novel, simple method of direct iodination is worthy to be extended to other appropriate aromatics.
- Lulinski, Piotr,Skulski, Lech
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p. 1665 - 1669
(2007/10/03)
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