- Synthesis of the first radiolabeled 188Re N-heterocyclic carbene complex and initial studies on its potential use in radiopharmaceutical applications
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A novel approach towards the synthesis of radiolabeled organometallic rhenium complexes is presented. We successfully synthesized and analyzed the first 188Re-labeled N-heterocyclic biscarbene complex, trans-dioxobis(1,1′-methylene-bis(3,3′-diisopropylimidazolium-2- ylidene))188rhenium(V) hexafluorophosphate (188Re-4) via transmetalation using an air-stable and moisture-stable silver(I) biscarbene complex. In order to assess the viability of this complex as a potential lead structure for in vivo applications, the stability of the 188Re-NHC complex was tested in physiologically relevant media. Ultimately, our studies illustrate that the complex we synthesized dissociates rapidly and is therefore unsuitable for use in radiopharmaceuticals. However, it is clear that the transmetalation approach we have developed is a rapid, robust, and mild method for the synthesis of new 188Re-labeled carbene complexes. Copyright
- Wagner, Thomas,Zeglis, Brian M.,Groveman, Sam,Hille, Claudia,Poethig, Alexander,Francesconi, Lynn C.,Herrmann, Wolfgang A.,Kuehn, Fritz E.,Reiner, Thomas
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- Synthesis, structures, and reactivity of chelating bis-N-heterocyclic- carbene complexes of iron(II)
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Distorted tetrahedral (bis-carbene)FeX2 complexes can be synthesized by direct metalation of chelating bisimidazolium salts, containing CH2 or phenylene linkers, with Fe(N(SiMe3) 2)2(THF). For methylenebis(N-R-imidazole-2-ylidene) ((RC)2CH2), the high-spin complexes (( RC)2CH2)FeX2 (R = iPr or 2,6-di-isopropylphenyl (DIPP), X = I or Br) are isolated in good to excellent yield. In contrast the phenylene-linked congener ((iPrC) 2Ph)FeI2 cannot be separated from two co-products, one of which was characterized by X-ray crystallography and zero-field 57Fe Moessbauer spectroscopy as the square-planar complex [((iPrC) 2Ph)2Fe[I2. The disparate reactivity toward Fe(N(SiMe3)2)2(THF) is due to the increase in linker length and decrease in linker flexibility of the phenylene-linked bis-carbene ligand relative to the methylene analogue. The short, flexible -CH2- linker projects the azole rings into the xy plane (defined as the carbene-Fe bond directions) and away from the pseudoaxial anionic substituent, whereas the inflexible phenylene linker ((RC) 2Ph) orientates both azole rings into the z direction, which in ((RC)2Y)FeX2 species (Y = CH2 or phenylene) has the greatest steric crowding. Metallacycle distortion in tetrahedral ((RC)2Ph)FeX2 is necessary to project the azoles into the xy plane, destabilizing this geometry. Addition of CO to ((DIPPC)2CH2)FeI2 forms cis-((DIPPC)2CH2)FeI2(CO) 2, in which the carbene ligands are strong σ donors based on ν(CO). Halide metathesis of ((DIPPC)2CH 2)FeI2 with NaSMe cleanly forms ((DIPPC) 2CH2)FeI(SMe), while attempts to exchange the second iodide for -SMe led to carbene dissociation.
- Zlatogorsky, Sergey,Muryn, Christopher A.,Tuna, Floriana,Evans, David J.,Ingleson, Michael J.
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- Synthesis, crystal structures and blue emission of zinc(II) halide complexes of 1-alkyl-imidazole and (-)-nicotine
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Zn(II) halide complexes of the form L2ZnX2 (X =Cl, Br, I) containing bio-relevant or bio-related ligands like 1-alkyl-imidazoles (alkyl=methyl, ethyl and iso-propyl) or (-)-nicotine are presented. All complexes were characterized by 1H NMR spectroscopy, mass spectrometry and elemental analysis. The molecular structures of the majority of complexes were determined by single crystal X-ray diffraction. The zinc ion exists in a tetrahedral environment coordinated by two halide anions and two nitrogen atoms of the N-heterocycles. Upon photoexcitation the nicotine complexes feature a blue emission which we tentatively assign to phosphorescence.
- Hobbollahi, Elnaz,Veselkova, Barbora,List, Manuela,Redhammer, Günther,Monkowius, Uwe
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- A planar anthracene–imidazolium/anthracene–benzimidazolium cation system in a spherical polyoxometalate matrix: Synthesis, crystallography and spectroscopy
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A series of ion–pair compounds, comprising of Lindqvist type isopolyanions viz., [Mo6O19]2?and [W6O19]2?as the counter anions and anthracene–imidazolium/anthracene–benzimidazolium as counter cations, have been described. Structures of the isolated stoichiometric solids have been unambiguously determined by single crystal X-ray diffraction analysis. In spite of the structural incompatibility between anthracene (planar) and the present polyoxometalate anions (spherical), coulombic and several intermolecular weak interactions, e.g. C–H?O, C–H?π, π–π, etc. compensate the destabilization energy raised due to presence of the structurally mis-matched components in the respective crystal lattices. Single-crystal- as well as powder X-ray-diffraction (PXRD) analyses reveal iso-structural relationship between the hexamolybdates- and hexatungstates-associated ion pair compounds. Conformational variation has been observed in the crystal structures containing benzyl benzimidazolium counter cations. Diffuse reflectance electronic absorption spectral studies are performed to understand the relatively intense color of the title compounds in their solid states in comparison to their respective solution states.
- Chatterjee, Tanmay,Kumar, N. Tanmaya,Das, Samar K.
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- Process for the preparation of 1-hexene and 1-oxtene
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The present invention relates to a manufacturing method of 1-hexene and 1-octene from an olefin under the presence of a catalyst composition. The catalyst composition comprises: at least one type of an organic ligand compound selected from the group consisting of a compound represented by chemical formula 1, a compound represented by chemical formula 2, and a compound represented by chemical formula 3; at least one type of transition metal or a transition metal precursor selected from the group consisting of group IV to group XII elements; and a promotor. The manufacturing method of the present invention reduces generation of byproducts, and can manufacture 1-hexene and 1-octene from an olefin with high selectivity and reaction activity.
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Paragraph 0110-0114
(2017/05/18)
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- N-heterocyclic carbene-catalyzed α-alkylation of ketones with primary alcohols
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Several N-heterocyclic carbene precursors are synthesized and used in the α-alkylations of ketones with primary alcohols. With the assistance of a base, these N-heterocyclic carbenes can catalyze the reaction smoothly to furnish dialkylated ketones in good-to-excellent yields.
- Zhu, Yanfang,Cai, Chun,Lu, Guoping
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p. 1666 - 1671
(2015/01/09)
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- Convenient syntheses of bulky group containing imidazolium ionic liquids
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We report syntheses of bulky group containing imidazolium based ionic liquids. The bulky groups were introduced at N-1, C-2, and N-3 positions of the imidazole ring using convenient methodologies. Copyright
- Kumar, Neeraj,Jain, Rahul
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experimental part
p. 370 - 374
(2012/06/04)
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- USE OF PT-AND PD-BIS-AND TETRA-CARBON COMPLEXES WITH BRIDGED CARBON LIGANDS IN OLEDS
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The use of Pt- and Pd-bis- and tetracarbene complexes with bridged carbene ligands in organic light-emitting diodes, organic light-emitting diodes comprising at least one aforementioned Pt- or Pd-carbene complex, at least one transition metal-carbene comp
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Page/Page column 7
(2010/01/31)
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- Synthesis of 1,3-dialkylimidazolium and 1,3-dialkylbenzimidazolium salts
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A number of N-alkylimidazoles and N-alkylbenzimidazoles were synthesized by reactions of imidazole and benzimidazole with alkyl halides. The reaction rate increases by a factor of 2 to 3 under conditions of microwave activation. Subsequent treatment of the resulting N-alkylazoles with alkyl halides afforded the corresponding 1,3-dialkylimidazolium and 1,3-dialkylbenzimidazolium halides.
- Starikova,Dolgushin,Larina,Ushakov,Komarova,Lopyrev
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p. 1467 - 1470
(2007/10/03)
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- Optically active iridium imidazol-2-ylidene-oxazoline complexes: Preparation and use in asymmetric hydrogenation of arylalkenes
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This work explores the potential of iridium complexes of the N-heterocyclic carbene oxazoline ligands 1 in asymmetric hydrogenations of arylalkenes. The accessible carbene precursors, imidazolium salts 2, and robust iridium complexes 5 facilitated a disco
- Perry, Marc C.,Cui, Xiuhua,Powell, Mark T.,Hou, Duen-Ren,Reibenspies, Joseph H.,Burgess, Kevin
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p. 113 - 123
(2007/10/03)
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- Process for manufacture of imidazoles
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Imidazoles may be manufactured by reacting a glyoxal, ammonia, an aldehyde, and optionally a primary amine, in the presence of a Bronsted acid whose pKa is approximately equal to the pKa of the ammonium cation of the primary amine, or if the primary amine is not present, to the pKa of the ammonium (NH4+) cation. The reaction may be used to make in relatively high yields a wide variety of imidazoles using relatively inexpensive starting materials. The imidazoles are useful as chemical intermediates.
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- 1,2,3-Benzothiadiazole derivatives
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Novel 1,2,3-benzothiadiazole derivatives of the formula STR1 in which Het has the meanings set forth in the specification, and addition products thereof with an acid or metal salt are very effective for the control of undesired microorganisms. Novel intermediates of the formulae STR2 in which Het1 and R5 have the meanings given in the specification.
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- Chloropyridylcarbonyl derivatives
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Novel chloropyridylcarbonyl derivatives of the formula STR1 in which Het is STR2 n is 1 or 2, R1 is hydrogen, optionally substituted C1-6 alkyl, optionally substituted C2-6 alkenyl, optionally substituted C3-6 alkynyl, optionally substituted phenyl or optionally substituted pyrimidinyl, and R2 and R3, independently of each other, are hydrogen or C1-4 alkyl, and acid addition salts and metal salt complexes thereof, are outstandingly active as microbicides.
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- Hofmann-type elimination in the efficient N-alkylation of azoles: Imidazole and benzimidazole
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A simple and efficient preparation of 1-substituted 1H-azoles (imidazole and benzimidazole) has been developed, which involves a selective Hofmann-type elimination of the 2-cyanoethyl group from the azolium salts obtained by the reaction of halides with 1H-imidazole-1-propanenitrile and 1H-benzimidazole-1-propanenitrile. Overall yields of 1-substituted 1H-azoles decreased in the order: primary alkyl halides ≥ allylhalides ≥ secondary alkyl halides ≥ benzyl halides > α-keto halides, in relation to the alkylating agent, and imidazole ≥ benzimidazole, in relation to the azole, respectively.
- Horvath
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p. 102 - 106
(2007/10/02)
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- Synthesis of 1-alkylimidazoles
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A mechanistic investigation of the synthesis of imidazole and 1- alkylimidazoles has led to an improved synthesis starting from glyoxal, formaldehyde and alkylammonium chlorides.
- Gridnev,Mihaltseva
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p. 1547 - 1555
(2007/10/02)
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