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81.
Heinrich Lang Bettina Lühmann Roy Buschbeck 《Journal of organometallic chemistry》2004,689(22):3598-3603
A straightforward method for the preparation of metallo carbosiloxanes of type Si(OCH2CH2CH2SiMe2[OCH2PPh2M(CO)n])4 (n = 3, M = Ni, 7a; n = 4, M = Fe, 7b; n = 5: M = Mo, 7c; M = W, 7d), Si(OCH2CH2CH2SiMe[OCH2PPh2Ni(CO)3]2)4 (8) and Me2Si(OCH2CH2CH2SiMe[OCH2PPh2Ni(CO)3]2)2 (11) is described. The reaction of Si(OCH2CH2CH2SiMeXCl)4 (1: X = Me, 2: X = Cl) or Me2Si(OCH2CH2CH2SiMeCl2)2 (9) with HOCH2PPh2 (3) produces Si(OCH2CH2CH2SiMe2(OCH2PPh2))4 (4), Si(OCH2CH2CH2SiMe(OCH2PPh2)2)4 (5) or Me2Si(OCH2CH2CH2SiMe(OCH2PPh2)2)2 (10) in presence of DABCO. Treatment of the latter molecules with Ni(CO)4 (6a), Fe2(CO)9 (6b), M(CO)5(Thf) (6c: M = Mo; 6d: M = W), respectively, gives the title compounds 7a-7d, 8 and 11 in which the PPh2 groups are datively bound to a 16-valence-electron metal carbonyl fragment.The formation of analytical pure and uniform branched and dendritic metallo carbosiloxanes is based on elemental analysis, and IR, 1H, 13C{1H}, 29Si{1H} and 31P{1H} NMR spectroscopic studies. In addition, ESI-TOF mass spectrometric studies were carried out. 相似文献
82.
Crawford MJ Ellern A Karaghiosoff K Mayer P Nöth H Suter M 《Inorganic chemistry》2004,43(22):7120-7126
The synthesis and characterization of the dioxouranium(VI) dibromide and iodide hydrates, UO(2)Br(2)x3H(2)O (1), [UO(2)Br(2)(OH(2))(2)](2) (2), and UO(2)I(2)x2H(2)Ox4Et(2)O (3), are reported. Moreover, adducts of UO(2)I(2) and UO(2)Br(2) with large, bulky OP(NMe(2))(3) and OPPh(3) ligands such as UO(2)I(2)(OP(NMe(2))(3))(2) (4), UO(2)Br(2)(OP(NMe(2))(3))(2) (5), and UO(2)I(2)(OPPh(3))(2)(6) are discussed. The structures of the following compounds were determined using single-crystal X-ray diffraction techniques: (1) monoclinic, P2(1)/c, a = 9.7376(8) A, b = 6.5471(5) A, c = 12.817(1) A, beta = 94.104(1) degrees , V = 815.0(1) A(3), Z = 4; (2) monoclinic, P2(1)/c, a = 6.0568(7) A, b = 10.5117(9) A, c = 10.362(1) A, beta = 99.62(1) degrees , V = 650.5(1) A(3), Z = 2; (4) tetragonal, P4(1)2(1)2, a = 10.6519(3) A, b = 10.6519(3) A, c = 24.0758(6) A, V = 2731.7(1) A(3), Z = 4; (5) tetragonal, P4(1)2(1)2, a = 10.4645(1) A, b = 10.4645(1) A, c = 23.7805(3) A, V = 2604.10(5) A(3), Z = 4, and (6) monoclinic, P2(1)/c, a = 9.6543(1) A, b = 18.8968(3) A, c = 10.9042(2) A, beta =115.2134(5) degrees , V = 1783.01(5) A(3), Z = 2. Whereas 1 and 2 are the first UO(2)Br(2) hydrates and the last missing members of the UO(2)X(2) hydrate (X = Cl --> I) series to be structurally characterized, 4 and 6 contain room-temperature stable U(VI)-I bonds with 4 being the first structurally characterized room temperature stable U(VI)-I compound which can be conveniently prepared on a gram scale in quantitative yield. The synthesis and characterization of 5 using an analogous halogen exchange reaction to that used for the preparation of 4 is also reported. 相似文献
83.
Heinrich Trischler Thomas Höchfurtner Martin Ruff Christian Paulik 《Kinetics and Catalysis》2013,54(5):559-565
The influence of the concentration of the co-catalysts triethylaluminium (TEAL), tri-iso-butylaluminium (TIBAL), tri-n-octylaluminium on the polymerization rate for standard Ziegler-Natta catalyst systems was studied. By comparing the influence of monomeric TIBAL with TEAL co-catalyst on the polymerization activity, the effect of TEAL dimerization was described. The use of the Eley-Ridealadsorption model instead of Langmuir-Hinselwood model is proposed for the absorption of monomeric aluminiumalkyl species and for the formation of active centers C*. It is further proposed that steric hindrance from different co-catalysts, which results in a higher molecular weight (MW) of polymers, is caused by active centers with reduced space for chain transfer reactions. 相似文献
84.
85.
Martin Lamač Jiří Tauchman Sascha Dietrich Ivana Císařová Heinrich Lang Petr Štěpnička 《应用有机金属化学》2010,24(4):326-331
Amide coupling of (Sp)‐2‐(diphenylphosphanyl)ferrocene‐1‐carboxylic acid with appropriate terminal amines mediated by 1‐hydroxybenzotriazole and a carbodiimide affords multi‐donor amides terminally functionalized with planar‐chiral (Sp)‐2‐(diphenylphosphanyl)ferrocen‐1‐yl moieties in good to excellent yields. Palladium catalysts based on these ligands efficiently promote asymmetric allylic alkylation of 1,3‐diphenylallyl acetate with in situ generated dimethyl malonate anion to give the C‐alkylated product with ees up to 93% at room temperature. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
86.
Francis R. Costa Sudip Pradhan Udo Wagenknecht Anil K. Bhowmick Gert Heinrich 《Journal of Polymer Science.Polymer Physics》2010,48(22):2302-2311
In elastomer/organo clay nanocomposites, the morphological characteristics, and hence the mechanical properties, of the vulcanizates are strongly influenced by the organic modifier and the vulcanization process. When the elastomer itself undergoes strain‐induced crystallization, both the organic modifier and the dispersed filler particles could significantly influence the crystallization process. These phenomena are very common in case of natural rubber‐based vulcanizates. In this study, the similar effects have been demonstrated with carboxylated nitrile rubber (XNBR) and organically modified layered double hydroxide (O‐LDH)‐based nanocomposites. The effect of size of the organic modifier was obviously visible on the interlayer distance of O‐LDH and also on the morphological reorganization of the dispersed O‐LDH particles during vulcanization process. The strain‐induced crystallization of the XNBR was found to be strongly dependent on the morphological change that occurs during vulcanization process. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010 相似文献
87.
Rico Packheiser Tobias Rüffer Petra Ecorchard Prof. Dr. Heinrich Lang 《无机化学与普通化学杂志》2010,636(15):2607-2616
The synthesis of a unique series of heteromultinuclear transition metal compounds is reported. Complexes 1‐I‐3‐Br‐5‐(FcC≡C)‐C6H3 ( 4 ), 1‐Br‐3‐(bpy‐C≡C)‐5‐(FcC≡C)‐C6H3 ( 6 ), 1,3‐(bpy‐C≡C)2‐5‐(FcC≡C)‐C6H3 ( 7 ), 1‐(XC≡C)‐3‐(bpy‐C≡C)‐5‐(FcC≡C)‐C6H3 ( 8 , X = SiMe3; 9 , X = H), 1‐(HC≡C)‐3‐[(CO)3ClRe(bpy‐C≡C)]‐5‐(FcC≡C)‐C6H3 ( 11 ), 1‐[(Ph3P)AuC≡C]‐3‐[(CO)3ClRe(bpy‐C≡C)]‐5‐(FcC≡C)‐C6H3 ( 13 ), 1‐[(Ph3P)AuC≡C]‐3‐(bpy‐C≡C)‐5‐(FcC≡C)‐C6H3 ( 14 ), [1‐[(Ph3PAuC≡C]‐3‐[{[Ti](C≡CSiMe3)2}Cu(bpy‐C≡C)]‐5‐(FcC≡C)‐C6H3]PF6 ( 16 ), and [1,3‐[(tBu2bpy)2Ru(bpy‐C≡C)]2‐5‐(FcC≡C)‐C6H3](PF6)4 ( 18 ) (Fc = (η5‐C5H4)(η5‐C5H5)Fe, bpy = 2,2′‐bipyridiyl‐5‐yl, [Ti] = (η5‐C5H4SiMe3)2Ti) were prepared by using consecutive synthesis methodologies including metathesis, desilylation, dehydrohalogenation, and carbon–carbon cross‐coupling reactions. In these complexes the corresponding metal atoms are connected by carbon‐rich bridging units comprising 1,3‐diethynyl‐, 1,3,5‐triethynylbenzene and bipyridyl units. They were characterized by elemental analysis, IR and NMR spectroscopy, and partly by ESI‐TOF mass spectrometry., The structures of 4 and 11 in the solid state are reported. Both molecules are characterized by the central benzene core bridging the individual transition metal complex fragments. The corresponding acetylide entities are, as typical, found in a linear arrangement with representative M–C, C–CC≡C and C≡C bond lengths. 相似文献
88.
Hydroperoxides, olefins, and arenediazonium salts selectively combine to give azo compounds via an iron(II)-mediated three-component reaction. Starting with a fragmentation liberating acetic acid, the hydroperoxides act as radical source and the diazonium ions as nitrogen-centered radical scavengers. 相似文献
89.
Martin Körsgen Andreas Pelster Klaus Dreisewerd Heinrich F. Arlinghaus 《Journal of the American Society for Mass Spectrometry》2016,27(2):277-284
The analytical sensitivity in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is largely affected by the specific analyte-matrix interaction, in particular by the possible incorporation of the analytes into crystalline MALDI matrices. Here we used time-of-flight secondary ion mass spectrometry (ToF-SIMS) to visualize the incorporation of three peptides with different hydrophobicities, bradykinin, Substance P, and vasopressin, into two classic MALDI matrices, 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (HCCA). For depth profiling, an Ar cluster ion beam was used to gradually sputter through the matrix crystals without causing significant degradation of matrix or biomolecules. A pulsed Bi3 ion cluster beam was used to image the lateral analyte distribution in the center of the sputter crater. Using this dual beam technique, the 3D distribution of the analytes and spatial segregation effects within the matrix crystals were imaged with sub-μm resolution. The technique could in the future enable matrix-enhanced (ME)-ToF-SIMS imaging of peptides in tissue slices at ultra-high resolution. 相似文献
90.
Steinmetz H Irschik H Kunze B Reichenbach H Höfle G Jansen R 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(20):5822-5832
Two novel antibiotics, thuggacin A (1) and B (2), were isolated from the myxobacterium Sorangium cellulosum. 1 and 2 are unique thiazole-containing macrolides with side chains on both sides of the lactone group. Upon standing in solution, thuggacin A (1) rearranges by acyl migration of the lactone group to give a mixture with thuggacins B (2) and C (3). NOEs and vicinal coupling constants within the lactone ring provided distinct data for the generation of a structure model by PM3 calculations, which allowed an analysis of the conformation in solution and the relative configuration of six asymmetric centres. A minor sorangium metabolite was identified as 13-methyl-thuggacin A (4). Furthermore, two natural thuggacin variants, 5 and 6, were found in another myxobacterium, Chondromyces crocatus. In these variants, one side chain is replaced by a methyl group and a hydroxy group is repositioned to give a primary alcohol at the former methyl site, in an alpha position with respect to the thiazole ring. 1 proved to be active against clinical isolates and reference strains of Mycobacterium tuberculosis. Preliminary studies on the mechanism of action indicate inhibition of the cellular electron-transport chain. 相似文献