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1Author    Walter Strohmeier, Erich HitzelRequires cookie*
 Title    Katalytische Aktivität von homogenem und heterogenisiertem RhCl(PPh3)3 für die Hydrierung von Substraten ohne Solvens Catalytic Activity of Homogeneous and Heterogenized RhCl(PPh3)3 for Hydrogenation of Substrates without Solvents  
  Reference    (Z. Naturforsch. 31b, 945—947 [1976]; eingegangen am 2. März 1976) 
  Published    1976 
  Keywords    Catalysis, Hydrogenation, Rhodium 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-0945.pdf 
 Identifier    ZNB-1976-31b-0945 
 Volume    31 
2Author    Valerie Bertagna, Francis Rouelle, Marius ChemlaRequires cookie*
 Title    Copper Contamination Mechanism of Silicon Substrates from HF Solutions  
 Abstract    The contamination of silicon wafers from dilute HF solutions containing ultratrace levels of metallic ion impurities is a subject of constant interest. The mechanism of copper electroless deposition from HF onto monocrystalline silicon was investigated using a new electrochemical cell, which proved to be a very sensitive detector for in situ characterization of silicon surfaces. Upon addition of copper trace amounts, the open-circuit potential was observed to shift rapidly towards more positive values at a rate nearly proportional to the copper concentration. All poten-tial/time curves tend to reach a limiting value of the potential, while quantitative measurements of radioactive tracers revealed that during a few tens of minutes, copper ions were continuously reduced on the silicon surface. Electrochemical potentials and voltammetric measurements were interpreted in terms of the mixed potential theory and led to the conclusion that copper nuclei act as a catalyst which enhances the cathodic activity for protons reduction. The model was supported by AFM observations which demonstrated the initiation of corrosion pits around the nuclei. 
  Reference    Z. Naturforsch. 52a, 465—176 (1997); received April 14 1997 
  Published    1997 
  Keywords    Silicon, contamination, copper, catalysis 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0465.pdf 
 Identifier    ZNA-1997-52a-0465 
 Volume    52 
3Author    Requires cookie*
 Title    Catalytic Hydrogenation of U nsaturated Compounds with H 2PtC l6-SnCl2 * 2 H ,0 in Acetic Acid  
 Abstract    W a l t e k S t r o h m e ie r und M a g d a le n a P f ö h l e r A hydrogenation catalyst, operating under mild conditions can be prepared by dissolving H 2PtC l6 and SnCl2 • 2 H 20 in acetic acid. After injection of an unsaturated compound under a H 2-atmosphere the active m oiety of the catalyst is generated. No active m oiety of catalyst is formed if the compound has a triple bond. But acetylenic derivatives are hydrogenated if the active m oiety of the catalyst is first produced by hydrogenation of cyclohexene. 
  Reference    (Z. Naturforsch. 30b, 466—467 [1975]; eingegangen am 27. Januar 1975) 
  Published    1975 
  Keywords    Catalysis, Hydrogenation, Unsaturated Compounds 
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 TEI-XML for    default:Reihe_B/30/ZNB-1975-30b-0466_n.pdf 
 Identifier    ZNB-1975-30b-0466_n 
 Volume    30 
4Author    Walter Strohmeier, Luise WeigeltRequires cookie*
 Title    Homogeneous Catalytic Hydrogenation of Unsaturated Compounds with H2PtCl6 + SnCl2 * 2 H20 in iso-Propanol  
 Abstract    A catalytical system for homogeneous hy-drogenation of unsaturated compounds, oper-ating under mild conditions can be prepared with H2PtCl6-SnCl2 • 2 H20 and the additives HBr and H20 in m>-propanol. Reaction rates up to 32 mMol • 1 _1 • min -1 were observed. After hydrogenation of one batch new sub-strate can be injected several times without noticeable desactivation of the system. Hy-drogenation rate of 2-tr-cis-hexene is only 0,5 times less than of 1-hexene. Mesityloxide is selectively hydrogenated regarding the double bond. 
  Reference    (Z. Naturforsch. 31b, 387—389 [1976]; eingegangen am 17. Oktober 1975) 
  Published    1976 
  Keywords    Catalysis, Hydrogenation, Unsaturated Compounds 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-0387_n.pdf 
 Identifier    ZNB-1976-31b-0387_n 
 Volume    31 
5Author    Walter Strohmeier, Magdalena PföhlerRequires cookie*
 Title    Homogeneous and Heterogeneous Catalytic Hydrogenation of Unsaturated Compounds with H2PtCl6 + SnCl2 * 2 H20 in Acetic Acid  
 Abstract    The hydrogenation catalyst, prepared by dissolving H2PtCl6 + SnCl2 • 2 H20 in acetic acid operates as a homogeneous or heteroge-neous catalyst, depending on the ratio v = Sn/Pt. Styrene is hydrogenated by the homo-geneous and heterogeneous system but cyclo-hexene only by the heterogeneous system. 
  Reference    (Z. Naturforsch. 31b, 390—392 [1976]; eingegangen am 17. Oktober/24. November 1975) 
  Published    1976 
  Keywords    Catalysis, Hydrogenation, Unsaturated Compounds 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-0390_n.pdf 
 Identifier    ZNB-1976-31b-0390_n 
 Volume    31 
6Author    Erich HitzelRequires cookie*
 Title    Abbau von Induktionsperioden und Steigerung der Aktivität homogener Hydrierungskatalysatoren mit Iridium als Zentralatom Reduction of Induction Periods and Increase of Activity of Homogenous Iridium Hydrogenation Catalysts  
 Abstract    With complexes of iridium as catalysts, induction periods are typical for homogeneous hydrogenation of olefins in bulk. The induction period decreases, as a rule with increasing activity, at higher temperatures and may be suppressed with dibenzoylperoxide, azo-bisisobutyrodinitrile, tetrachloro-l,4-benzoquinone or by preactivation. Triethylamin and SnCl2 • 2H2O are unsuitable additives. The operation "preactivation" leads additionally to great substrate/catalyst-turnover numbers. 
  Reference    Z. Naturforsch. 33b, 997—1000 (1978); eingegangen am 19. Juni 1978 
  Published    1978 
  Keywords    Catalysis, Hydrogenation, Induction Periods, Activity 
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 TEI-XML for    default:Reihe_B/33/ZNB-1978-33b-0997.pdf 
 Identifier    ZNB-1978-33b-0997 
 Volume    33 
7Author    Walter Strohmeier, Johannes-Peter StaschRequires cookie*
 Title    Photoaktivierung und Photosensibilisierung des homogenen Hy drierungs -Katalysators IrCl(CO) [P(i-C3H7)3] 2 Photoactivation and Photosensitization of the Homogeneous Hydrogenation Catalyst IrCl(CO)[P(i-C3H7)3]2  
 Abstract    Under irradiation with monochromatic light of X < 407 nm homogeneous hydrogenation of acrylic ethvlester with the catalyst IrCl(CO)[P"(i-C3H7)3]2 is much faster than in the dark reaction. Not the catalyst but the hydrido-complex is photochemically activated. With the sensitizer pentacene, photoactivation occurrs with visible light of X < 578 nm already. 
  Reference    Z. Naturforsch. 34b, 755—758 (1979); eingegangen am 31. Januar 1979 
  Published    1979 
  Keywords    Photoactivation, Photosensitization, Hydrogenation, Catalysis 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-0755_n.pdf 
 Identifier    ZNB-1979-34b-0755_n 
 Volume    34 
8Author    Henri Brunner, Bernd HaßlerRequires cookie*
 Title    Enantioselective Catalysis, 122 [1] Synthesis of New Optically Active 3.5-DinitrosalicyloxazoIines  
 Abstract    New optically active 3,5-dinitrosalicyloxazo-lines, derived from 3,5-dinitrosalicylonitrile and the chiral aminodiols (lS,2S)-(+)-2-am ino-l-phe-nyl-l,3-propanediol, (2S)-(-)-2-amino-l,l,4,4-te-traphenyl-l,4-butanediol and (2S)-(-)-2-amino-l,l-diphenyl-l,3-butanediol, were prepared and used as in situ catalysts for enantioselective cyclo-propanation reactions. 
  Reference    (Z. Naturforsch. 53b, 126—128 [1998]; eingegangen am 27. O ktober 1997 3.) 
  Published    1998 
  Keywords    5-Dinitrosalicyloxazolines, Enantioselectivity, Catalysis, Cyclopropanations 
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 TEI-XML for    default:Reihe_B/53/ZNB-1998-53b-0126_n.pdf 
 Identifier    ZNB-1998-53b-0126_n 
 Volume    53 
9Author    Henri Brunner, Bernd HaßlerRequires cookie*
 Title    Enantioselective Catalysis, 120 [1] New Optically Active Pyrrole-oxazolines  
 Abstract    14 new optically active pyrrole-oxazolines were synthesised from 2-pyrrole-carbonitrile or methyl 2-pyrrole-carboximidate and chiral amino alcohols. Their use in copper-catalysed enan­ tioselective cyclopropanation reactions gave only low optical yields (3-14%ee). 
  Reference    Z. Naturforsch. 53b, 476—480 (1998); received January 12 1998 
  Published    1998 
  Keywords    Pyrrole-oxazolines, Enantioselectivity, Catalysis, Cyclopropanations 
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 TEI-XML for    default:Reihe_B/53/ZNB-1998-53b-0476.pdf 
 Identifier    ZNB-1998-53b-0476 
 Volume    53 
10Author    J. M. Ramallo-López, F. G. Requejo, A. G. Bibiloni, M. Rentería, L. Gutierrez, E. E. MiróRequires cookie*
 Title    Combined TDPAC and EXAFS Study of InPt/FER Catalysts  
 Abstract    Time Differential Perturbed Angular Correlation (TDPAC) experiments using 111 In as probe were performed in order to determine the nature of In-sites in In-ferrierite (In/FER), before and after the incorporation of Pt through the hyperfine interaction between the nuclear quadrupole moment of the probe's nucleus and the extranuclear electric field gradient (EFG). Extended X-ray Absorption Fine Structure (EXAFS) measurements were performed to measure the absorbance above the Pt's L m absorption edge in the transmission mode in order to determine the local environment of Pt atoms in Pt/FER and InPt/FER catalysts. TDPAC spectra of 111 In in In/FER and InPt/FER taken at 500°C in air indicated that there are no changes in the indium surroundings after the incorporation of Pt. Three sites were found for indium in both samples. Two of them correspond to the two sites of indium in ln 2 0 3 and the third one is attributed to In in exchange sites of the zeolites. Their population, quadrupole frequencies and asymmetry parameters didn't change with the incorporation of Pt. EXAFS experiments showed similar near neighborhood Pt-0 distances and Pt coordination number in Pt/FER and InPt/FER samples. There is no evidence of the presence of any In-Pt bimetallic entity in InPt/FER catalyst. 
  Reference    Z. Naturforsch. 55a, 327—330 (2000); received August 26 1999 
  Published    2000 
  Keywords    Hyperfine Interactions, TDPAC, EXAFS, Catalysis, Ferrierite 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0327.pdf 
 Identifier    ZNA-2000-55a-0327 
 Volume    55 
11Author    Walter Strohmeier, Magdalena PföhlerRequires cookie*
 Title    Vergleich der Hydrierung ungesättigter Verbindungen mit einem homogenen und heterogenen Platin-Katalysator in Essigsäure Comparison of Hydrogenation of Unsaturated Compounds with a Homogeneous and Heterogeneous Platinum Catalyst in Acetic Acid  
 Abstract    Catalytical hydrogenation of unsaturated compounds in acetic acid with the homo-geneous catalyst prepared from H2PtCl6 + SnCl2 • 2 H20 and the heterogeneous catalyst, prepared from H2PtCl6 and H2, were carried out. A comparison of the results reveals two types of substrates, some are readily hydrogenated by the homogeneous the other ones by the heterogeneous system. Turnover numbers up to 1500 were observed. With the heterogeneous catalyst ethylbenzene is hydrogenated to ethylcyclohexane under mild conditions. 
  Reference    (Z. Naturforsch. 31b, 941—944 [1976]; eingegangen am 2. März 1976) 
  Published    1976 
  Keywords    Catalysis, Hydrogenation, Homogeneous Catalyst, Heterogeneous Catalyst 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-0941.pdf 
 Identifier    ZNB-1976-31b-0941 
 Volume    31 
12Author    Walter Strohmeier, Manfred Michel, Luise WeigeltRequires cookie*
 Title    mit homogenen Ir-und Ru-Katalysatoren Selective Bulk-Hydrogenation of a,ß Unsaturated Ketones to Ketones with Homogeneous Ir and Ru Catalysts  
 Abstract    a,ß Unsaturated ketones are selectively hydrogenated to ketones in homogeneous bulk-catalysis under mild conditions by iridium-and ruthenium complexes. The range of mean turnover is from 6 to 196 depending on substrate, catalyst and reaction conditions. Selectivity ketone/alcohol depends on the degree of conversion and exceeds 100 on con-version of 90%. Einleitende Bemerkungen 
  Reference    Z. Naturforsch. 35b, 648—650 (1980); eingegangen am 7. Dezember 1979 
  Published    1980 
  Keywords    Catalysis, Homogeneous, Selective, Hydrogenation, Unsaturated Ketones 
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 TEI-XML for    default:Reihe_B/35/ZNB-1980-35b-0648.pdf 
 Identifier    ZNB-1980-35b-0648 
 Volume    35 
13Author    WolfgangK. Läuia, Susanne Schoger2, Martin NiegerbRequires cookie*
 Title    Synthesis and Crystal Structure of Perhydro-l,4-benzoxazino[2,3-n]phenoxazine  
 Abstract    The oxidation of fra«s-2-aminocyclohexanol with nitrobenzene in the presence of catalytic amounts of iron inter alia yields perhydro-l,4-benzoxazino[2,3-n]phenoxazine (1). This com­ pound has been characterized analytically, spectroscopically and by X-ray diffraction. It is postulated that the oxidation of the 2-aminoalcohol leads to the intermediate formation of a 1,2-dione. The direct synthesis of 1 from trans-2-aminocyclohexanol and 1,2-cyclohexandione supports this hypothesis. 
  Reference    Z. Naturforsch. 52b, 801—804 (1997); eingegangen am 14. Oktober 1996 
  Published    1997 
  Keywords    Nitrobenzene, Reduction, Aniline, 2-Aminoalcohols, Catalysis 
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 TEI-XML for    default:Reihe_B/52/ZNB-1997-52b-0801.pdf 
 Identifier    ZNB-1997-52b-0801 
 Volume    52 
14Author    M. Fernanda, N. N. Carvalho3, ArmandoJ L Pombeiro3, Gabriele Wagner3, Bj0m Pedersenb, Rudolf HerrmannRequires cookie*
 Title    Cascade Reaction of Camphor-Derived Diynes with Transition Metal Compounds  
 Abstract    Platinum(II) catalyzes the isomerization o f camphor sulfonamide diynes in a cascade reaction involving annulation o f a five-membered ring to the camphor skeleton, ring-enlargement by C-C bond cleavage, reduction o f sulfur(VI) to sulfur(IV), and oxidation o f a hydroxy group to a ketone. The reactions o f the diynes with other transition metal compounds were also studied. Copper, gold and rhenium give final products similar to those obtained with simple Br0nsted acids or halogens, mainly by annulation o f a five-membered ring to the camphor moiety, accompanied by reduction o f a sulfonamide to a sulfinamide group, but lacking the ring-enlargement step. Palladium(II) occupies an intermediate position as both types o f products are obtained. The reaction mechanism and intermediates are discussed. 
  Reference    Z. Naturforsch. 54b, 725—733 (1999); received March 18 1999 
  Published    1999 
  Keywords    Camphor Diyne, Ring Enlargement, Transition Metals, Catalysis, Alkyne 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0725.pdf 
 Identifier    ZNB-1999-54b-0725 
 Volume    54 
15Author    Christian Egger, Ulrich SchubertRequires cookie*
 Title    Metallkomplexe in Anorganischen Matrices, 5 [1] Katalytische Silanoxidation an einem heterogenisierten Rhodium-Komplex M etal Complexes in Inorganic Matrices, 5 [1] Catalytic Silane Oxidation at a Heterogenized Rhodium Complex  
 Abstract    A heterogenized rhodium complex, prepared by sol-gel processing of Rh(CO)Cl[PPh2C H 2C H 2Si(OEt)3]2 and Si(OEt)4, is shown to catalyze the conversion of the si­ lanes H4_"SiPh" (n = 1 -3) or (H M e2Si)20 to (poly)siloxanes by air or water. Using T H F as a solvent, the silanoles Ph3SiOH or Ph2Si(OH)2 are obtained instead. The reaction of phenyl-acetic acid or acetic acid with HSiPh3 to give silyl esters is catalyzed by the same com pound. 
  Reference    Z. Naturforsch. 46b, 783—788 (1991); eingegangen am 14. Januar 1991 
  Published    1991 
  Keywords    Heterogenized Rhodium Complex, Catalysis, Silanes, Silanoles, Siloxanes, Silyl Esters 
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 TEI-XML for    default:Reihe_B/46/ZNB-1991-46b-0783.pdf 
 Identifier    ZNB-1991-46b-0783 
 Volume    46 
16Author    Stephan Pitter, EckhardD. Injus, Beate Jung, H. Elm, Ar GörlsRequires cookie*
 Title    Phosphinoalkylnitrile: Synthese und Koordinationsverhalten an Palladiumzentren Phosphinoalkylnitnles: Synthesis and Coordination Behaviour at Palladium C entres  
 Abstract    Phosphinoalkylnitriles R2P-(CH2)"-CN {R = isopropyl ('pr), phenyl (ph), cyclohexyl (' hex), n -3, 6, 10} have been prepared starting from the corresponding secondary phosphines in an easy three step synthesis. All new compounds were characterized by their 'H -, i3C and 31P NMR data. Some of these new P, N ligands were used to prepare complexes [{R2P-(CH2)"-CN}2PdCl2] which were also identified by their NMR data. In addition the crystal structures of three derivatives, [{'pr2P-(CH2)3-CN }2PdCl2] 7a, [{ph2P-(CH2)3-CN }2PdCl2) 7b and [{ph2P-(CH 2)6-CN}2PdCl2] 8b were determined by X-ray analysis. The coordination mode of the phosphinoalkylnitriles in these complexes was found to be P-bonded resulting in a trans configuration. Palladium catalysts with 5a as ligand show high activies in the co-oligomerization of butadiene and carbon dioxide. The ^-lactone 11a is formed under very mild conditions. 
  Reference    Z. Naturforsch. 51b, 934—946 (1996); eingegangen am 11. Juli 1995 
  Published    1996 
  Keywords    Phosphinoalkylnitriles, Phosphine Complexes of Palladium, Crystal Structure, Catalysis, -Lactones 
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 TEI-XML for    default:Reihe_B/51/ZNB-1996-51b-0934.pdf 
 Identifier    ZNB-1996-51b-0934 
 Volume    51