- Luminescence of Amphiphilic PtII Complexes Controlled by Confinement
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The formation of hybrid silica-based systems to study the effect of the confinement on the emission properties of self-assembled platinum(II) complexes is reported. The complexes behave as surfactants since they possess a hydrophobic moiety and, on the ancillary ligand, a relatively long hydrophilic chain terminated with a positively charged group. The compounds, soluble in water, self-assemble, even at very low concentration, in supramolecular structures which display an orange luminescence. The properties of the assemblies have been studied in detail and in order to stabilize these supramolecular architectures and to enhance their emission properties hybrid silica porous nanoparticles have been prepared. In particular the PtII complexes have been employed as co-surfactant for the template formation of mesoporous silica nanoparticles (MSNs) using a sol gel synthesis. Interestingly, upon encapsulation in the silica pores, the platinum aggregates exhibit an emission profile similar in energy to the complexes assembled in solution, but the photoluminescence quantum yields of the hybrid systems are significantly higher (up to 45 %), and the excited state lifetimes much longer than those recorded in solution. Such enhancement of the photophysical properties together with the possibility to process the hybrid silica nanomaterials can pave the way to new type of emitters.
- Atoini, Youssef,Prasetyanto, Eko Adi,Chen, Pengkun,Silvestrini, Simone,Harrowfield, Jack,De Cola, Luisa
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Read Online
- Impurity in tirofiban material, preparation of impurity, and method for detecting impurity in material
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The invention discloses an impurity in a tirofiban material, preparation of the impurity, and a method for detecting the impurity in the material. The impurity is a compound shown in a formula I, wherein R is selected from the following substituents: hydrogen, halogen, cyano group, amino, nitro, aryl and ceteroary; the R further is hydrogen or pyridyl. The method plays an important practical rolein improvement of the quality of the tirofiban and control of the safety of the tirofiban form the origin.
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Paragraph 0055; 0058; 0059; 0060; 0061
(2018/09/12)
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- Nitro-methyl redox coupling: Efficient approach to 2-hetarylbenzothiazoles from 2-halonitroarene, methylhetarene, and elemental sulfur
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A simple, straightforward, and atom economic approach to 2-hetarylbenzothiazoles starting from 2-halonitroarene, methylhetarene, and elemental sulfur under mild conditions is described. The method is highlighted by the direct redox nitro-methyl reaction for carbon-nitrogen bond formation without an added oxidizing or reducing agent.
- Nguyen, Thanh Binh,Ermolenko, Ludmila,Al-Mourabit, Ali
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supporting information
p. 4218 - 4221
(2013/09/12)
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- [2+2] Photodimerization of bispyridylethylenes by a controlled shift of the protonation equilibrium
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Irradiation of trans-4,4′-bispyridylethylene in the presence of 1 equiv of concd HCl produced a syn dimer with high selectivity, whereas irradiation in the presence of more than 2 equiv of concd HCl or in the absence of HCl gave a mixture of dimers and by-products with much lower selectivity. This indicated that a suitable amount of acid served as a catalyst for the [2+2] photodimerization of BPEs through cation-π interactions between the pyridinium and pyridine rings.
- Yamada, Shinji,Kusafuka, Momoko,Sugawara, Mai
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supporting information
p. 3997 - 4000
(2013/07/25)
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- Cocondensation reactions of heterocyclic aromatic compounds with lithium, calcium and magnesium atoms at 77 K
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Calcium and magnesium atoms were cocondensed with aromatic heterocycles containing five- and six-membered rings in the presence of THF at 77 K. In the case of calcium the cocondensation with five-membered heterocyclic compounds resulted in C-H bond activations and led to the corresponding aryl calcium compounds, while magnesium did not show comparable reactions. When six-membered heterocyclic compounds, e.g., pyridine and 4-methylpyridine (4-picoline) were cocondensed with calcium, magnesium and lithium atoms, all reactions led to the formation of non-metallated aromatic products and the formation of metal hydride. DFT calculations at the B3LYP/6-31G** level of theory were carried out in order to interpret the pathways of the cocondensation reactions using calcium atoms and identify the possible intermediates involved. In all reactions π- and σ-complexes between calcium atoms and the heterocyclic aromatic reactant were found as stable intermediates on the energy hypersurface.
- Mendoza, Oscar,Tacke, Matthias
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p. 1110 - 1116
(2007/10/03)
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- Oxidative coupling of methylpyridines
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The conversion of methylpyridines on melted and solid-state alkaline catalysts was studied over the temperature range 430-720°C. It was shown that melted catalysts are preferable for use in the oxidative coupling of methylpyridines. The melt NaOH + 10 wt% V2O5 turned out to be the most selective catalyst in the dimerization reaction of methylpyridines.
- Chekryshkin,Tetenova,Fedorov
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- ELEMENTAL SELENIUM REACTIONS WITH 4-PICOLINE
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A study of the reaction of the elemental selenium with 4-picoline is reported.The process was carried out at the boiling point of the 4-picoline under argon.After removing unreacted solids, the reaction products were identified by means of GC and GC-MS.Th
- Gleich, Edward,Warnke, Zygmunt
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- REACTIVITY OF HETEROAROMATIC ALDEHYDES WITH LOW VALENT TITANIUM
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Behaviour of various aromatic heterocycles under dicarbonylic coupling with low valent titanium was studied.The results showed that the electron donating properties of the ring affect the degree of oxidation of the coupled compound.
- Castedo, Luis,Cid, M. Magdalena,Dominguez, Rosa,Seijas, Julio A.,Villaverde, M. Carmen
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p. 1271 - 1274
(2007/10/02)
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- ELEMENTAL SULFUR REACTIONS WITH 4-PICOLINE
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A study of the reaction of the elemental sulfur with 4-picoline is reported.The process was carried out at the boiling point of the 4-picoline under argon.After removing unreacted solids, the reaction products were identified by means of LC, GC, and GC-MS
- Gleich Z.,Warnke, Z.,Szafranek, J.,Malinski, E.
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p. 315 - 326
(2007/10/02)
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- OXIDATIVE DIMERIZATION OF SUBSTITUTED o-METHYLPHENYL ISOCYANIDES; SYNTHESIS OF BIDENTATE BIS-ISONITRILE AND CYCLIC TETRADENTATE TETRAKIS-ISONITRILE LIGANDS
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Substituted o-methylphenyl isocyanides (1) were oxidatively dimerized via the corresponding o-lithiomethylphenyl isocyanides (2) by means of 1,2-dibromoethane to give 1,2-bis(2-isocyanophenyl)ethane derivatives (3). 1,2-Bis(2-isocyano-3-methylphenyl)ethane (3e), a coupling dimer of 2,6-xylyl isocyanide (1e), was further dimerized via its dilithiated intermediate to give a cyclic tetramer of 2,6-xylyl isocyanide (1e), which may be a cyclic tetradentate ligand for transition metal compounds.
- Ito, Yoshihiko,Kobayashi, Kazuhiro,Saegusa, Takeo
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p. 301 - 308
(2007/10/02)
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- Photostimulated Reactions of 2-Bromopyridine and 2-Chloroquinoline with Nitrile-Stabilized Carbanions and Certain Other Nucleophiles
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Potassiophenylacetonitrile (2) reacts with 2-bromopyridine (1) and 2-chloroquinoline (4) via the SRN1 mechanism when the reactants are exposed to near-UV light in liquid NH3.Potassioacetonitrile (6) reacts similarly with 1 and 4 upon photostimulation; however, the photo-SRN1 reaction with 1 is accompanied by SNAr2 amination which becomes the major reaction in the dark or in the presence of di-tert-butyl nitroxide.Substrate 4 undergoes competing SNAr2 amination with amide ion to form 2-aminoquinoline (10) and SN(ANRORC) reactions with both amide ion and carban ion 6 to form 3-methylquinazoline (11) and 2-methyl-3-cyanoquinoline (12), respectively.Formation of 12 becomes the major pathway in reactions between 4 and 6 carried out in the dark. 4-Picolylpotassium (14) reacts with 1, 4, and 4-bromopyridinium chloride (16) under photostimulation to form the appropriate dihetarylmethanes, along with the corresponding amino heterocycles.Amination of 1, 4, and 16 predominates when these reactions are carried out in the dark.Ammonium thiophenoxide (20) undergoes a slow photo-SRN1 reaction with 1 but fails to produce the expected 2-quinolyl phenyl sulfide with 4 after 2 h of irradiation.Potassium salts of acetylene, phenylacetylene, and phthalimide do not react with 1 or 4 after 2 h of exposure to near-UV light.
- Moon, Marcus P.,Komin, Andrew P.,Wolfe, James F.,Morris, Gene F.
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p. 2392 - 2399
(2007/10/02)
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- Pyridyl-substituted Cyclobutanes via Photodimerisation of Azastilbenes
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Mono- and diazastilbenes A1 - A9 as well as their mono- and dihydro- or -alkyl quaternary salts are irradiated (UV).Mono salts are smoothly converted into cyclobutanes C in crystalline state and/or in solution.The free bases A or their bis salts, reacting in solution only, from partly or exclusively different products.Their structures together with the constitutions and configurations of the cyclobutanes A are elucidated.Results from the literature are partly confirmed and partly corrected.
- Horner, Michael,Huenig, Siegfried
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p. 1183 - 1210
(2007/10/02)
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- Azastilbenes. 2. Photodimerization
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The photochemical behavior of several azastilbenes has been followed in concentrated solution and in the solid state.In acetonitrile and benzene isomerization and dimerization occur, the reactions being generally faster in acetonitrile.In methanol, however, photoreduction as well as photoaddition of the solvent intervene and are important processes.With irradiation in the solid state, dimerization occurs only for some azastilbenes and their quaternary salts, depending on the orientations of the molecules within the crystal lattice and the distances between adjacent double bonds (3.5-4.2 Angstroem).X-ray analysis has shown that trans-1,2-di(2-pyrazinyl)ethylene crystallizes in two distinct modifications of which only one has a crystal stacking suitable for topochemical dimer formation.The dimers were characterized by 1H and 13C NMR, IR, and mass spectroscopy.The crystalline and molecular structures of five of them were determined by X-ray diffraction, namely cyclobutane dimers of 1,2-di(4-pyridyl)ethylene, 1,2-di(2-pyridyl)ethylene, 1,2-di(2-pyrazinyl)ethylene (all three r-ctt dimers), and 1-(3-pyridyl)-2-(2-pyrazinyl)ethylene (r-ctt head-to-head and head-to-tail dimers).
- Vansant, J.,Toppet, S.,Smets, G.,Declercq, J. P.,Germain, G.,Meerssche, M. Van
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p. 1565 - 1573
(2007/10/02)
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