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1981 (332)
201Author    Requires cookie*
 Title    Die Struktur der bei der Korrosion von Kupfer in Gegenwart von 2-Aminopyrimidin (Sauerstoff, NaCl, pH 4,1, 22 °C) aufgebauten Schutzschicht  
  Reference    Z. Naturforsch. 36b, 989 (1981) 
  Published    1981 
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 Identifier    ZNB-1981-36b-0989 
 Volume    36 
202Author    Hermann LotterRequires cookie*
 Title    {Configurations*-Bestimmung von Isomeren des Methyl 4-0-Acetyl-2.3-0-(l-phenylethyliden)-a-L-rhamnopyranosides [1] The Configuration of Isomeres of Methyl 4-0-Acetyl-2,3-0-(l-phenylethylidene)-a-L-rhamnopyranoside [1]  
 Abstract    Diastereomeric 2,3-0[2-Phenyl-2-methyl-l,3 dioxalanes], X-ray The diastereomeric 2,3-0-[2-phenyl-2-methyl-l,3 dioxalanes] of methyl-a-L-rhamno-pyranosides were synthesised for the first time. The stereochemical characterisation was carried out by X-ray analysis. Evaluation of the X-ray data and comparison with NMR data indicated that the same configuration exists in the crystalline state as in solution. 
  Reference    Z. Naturforsch. 36b, 997—999 (1981); eingegangen am 26. März 1981 
  Published    1981 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-0997.pdf 
 Identifier    ZNB-1981-36b-0997 
 Volume    36 
203Author    PaavoH. Hynninen, Gunnel SieversRequires cookie*
 Title    Conformations of Chlorophylls a and a' and their Magnesium-Free Derivatives as Revealed by Circular Dichroism and Proton Magnetic Resonance  
 Abstract    The electronic absorption (UV/VIS), circular dichroism (CD) and proton magnetic resonance (*H NMR) spectra have been recorded for C-l0 epimeric chlorophylls a and a', pheophytins a and a' as well as pheophorbides a and a'. Although the epimers in each pair showed virtually identical UV/VIS spectra, their CD spectra were profoundly different and exhibited opposite signs at most wavelengths in the UV region. The differences were interpreted as arising, in part, from different C-10 configurations, and, in part, from conformational alterations induced by the steric strain in the crowded periphery of the macrocycle. The conformational alterations were also clearly indicated by the X H NMR zJö-values observed for the a,ß and <5 methine protons, the C-10 protons and most methyl group protons of the epimers in each pair. This was considered to imply changes in the geometry of the whole macrocycle. The A 6-values were larger for the Mg-free epimers than for the chlorophyll epimers, which shows that the central Mg-atom makes the macrocycle more rigid. Correlations between the signs of the CD bands and configurations are discussed. 
  Reference    Z. Naturforsch. 36b, 1000—1009 (1981); received May 19 1981 
  Published    1981 
  Keywords    Stereochemistry, Conformational Analysis, Chlorophyll and Pheophytin Epimers, X H NMR Spectra, Circular Dichroism 
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 Identifier    ZNB-1981-36b-1000 
 Volume    36 
204Author    PaavoH. HynninenRequires cookie*
 Title    Mechanism of the Allomerization of Chlorophyll: Inhibition of the Allomerization by Carotenoid Pigments  
 Abstract    Autooxidation of Chlorophyll, Free Radicals, Carotenoids, Photosynthesis It is shown that the allomerization of chlorophylls a and b is effectively inhibited by carotenoid pigments. In the light of this finding, two possible mechanisms are considered for the allomerization. One assumes the addition of singlet oxygen to the 9,10-double bond of the chlorophyll (Chi) enolate anion to yield a C-10 hydroperoxide or a dioxetane derivative. The other assumes a free-radical chain reaction involving Chi enolate anion, triplet oxygen, Chi C-10 radicals and peroxide radicals, and Chi C-10 hydroperoxide. The observation that the allomerization and its inhibition by carotenoids occur under carefully controlled dark conditions precluding singlet oxygen formation provides substantial support to the latter mechanism. Further evidence for the free-radical mechanism is obtained by observing the increase of the allomerization rate when air is replaced with pure oxygen from a container. The rate increases to about two-fold in the methanolic Chi solution containing no carotenoid but remains close to zero in the Chi solution containing an equimolar amount of ^-carotene. The relevance of the results to photosynthesis and cancer research is briefly discussed. 
  Reference    Z. Naturforsch. 36b, 1010—1016 (1981); received May 19 1981 
  Published    1981 
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 Identifier    ZNB-1981-36b-1010 
 Volume    36 
205Author    Herbert Meier, Johannes Zountsas, Oswald ZimmerRequires cookie*
 Title      
 Abstract    A X H and 13 C NMR spectroscopical study is performed on the basis of 37 1,2,3-selena-diazoles. Besides the discussion of chemical shifts and coupling constants of X H and 13 C, selenium satellites were measured providing 1 H 77 Se and 13 C 77 Se coupling constants. 
  Reference    Z. Naturforsch. 36b, 1017—1022 (1981); eingegangen am 16. April 1981 
  Published    1981 
  Keywords    NMR Spectra, 1, 2, 3-Selenadiazoles, 77 Se Coupling 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-1017.pdf 
 Identifier    ZNB-1981-36b-1017 
 Volume    36 
206Author    *-*, Gerhard Nonnenmacher, Gottfried Zimmermann®, Otto Isaac»Requires cookie*
 Title    Elmar Flaskamp  
 Abstract    The stereochemistry of the bisaboloids in chamomile—with the exception of bisabolol-oxide C—has been elucidated. The in-vitro-examination of the mutual convertibüities of some bisaboloids gave evidence for the stereochemical accordance of the common chiral centres of all the bisaboloids. The absolute configurations of the remaining third asym-metric carbon atoms in bisabololoxide A and B have been determined by NMR spectro-metric studies in comparison with their unnatural semisynthetic epimers. All the stereo-genie centres of the bisabololoxides A and B, of (—)-a-bisabolol and of bisabolonoxide A turn out to be S-configurated. 
  Reference    Z. Naturforsch. 36b, 1023—1030 (1981); eingegangen am 30. April 1981 
  Published    1981 
  Keywords    Matricaria chamomilla L, Bisaboloids, 13 C NMR Spectra, Shift-Reagents 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-1023.pdf 
 Identifier    ZNB-1981-36b-1023 
 Volume    36 
207Author    Wolf-H GündelRequires cookie*
 Title    Untersuchungen an quartären Pyridinium-Salzen, XTV [1] Dihydropyridyl-oxiinether Investigations of Quaternary Pyridinium Salts, XIV [1] Dihydropyridyl-oxime-ethers  
 Abstract    Pyridinium Salts with electron-withdrawing groups in the 3-position react with aliphatic ketoximes under basic conditions to lipophilic addition products, 6-(alkylideniminoxy)-1,6-dihydropyridines. 
  Reference    Z. Naturforsch. 36b, 1031—1036 (1981); eingegangen am 21. April 1981 
  Published    1981 
  Keywords    Pyridinium Salts, Insertion Reaction, Oximes 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-1031.pdf 
 Identifier    ZNB-1981-36b-1031 
 Volume    36 
208Author    Römer, H. Scholl, H. Budzikiewicz, H. Korth, G. PulvererRequires cookie*
 Title     
 Abstract    The structure elucidation of several minor phenazine pigments of Pseudomonads is described. 4-Hydroxyphenazine-l,6-dicarboxylic acid dimethyl ester, 2,3-dihydroxy-phenazine, 2,3,7-trihydroxyphenazine, 4-hydroxyphenazine-l-carboxylic acid, 2,3-di-hydroxyphenazine-l-carboxylic acid, 2,6-dihydroxyphenazine-l-carboxylic acid and 2,3,7-trihydroxyphenazine-l,6-dicarboxylic acid are new phenazine derivatives. The distribu-tion of phenazines in the genus Pseudomonas is investigated. 
  Reference    Z. Naturforsch. 36b, 1037—1046 (1981); eingegangen am 27. März 1981 
  Published    1981 
  Keywords    Phenazines, Bacterial Constituents, Pseudomonads, NMR Spectra, IR Spectra 
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 Identifier    ZNB-1981-36b-1037 
 Volume    36 
209Author    Masaru Ishida, Shinzi Kato, Masateru MizutaRequires cookie*
 Title    The Reaction of Dithiocarboxylic Acids with Imines  
 Abstract    Aromatic dithiocarboxylic acids 1 react with imines 4 to give the corresponding adducts 5, aminomethyl dithiocarboxylates, in good yields. The adducts 5 react with phenacyl bromide to give the corresponding phenacyl dithiocarboxy-lates 6. We have previously reported that the reaction of dithiocarboxylic acids (1) with various kinds of secondary and tertiary amines gave the correspond-ing salts (2) in excellent yields [1]. Recently, 
  Reference    Z. Naturforsch. 36b, 1047—1049 (1981); received April 29 1981 
  Published    1981 
  Keywords    Aryl Dithiocarboxylic Acids, Imines, Aminomethyl Dithiocarboxylates, Phenacyl Dithiocarboxylates 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-1047_n.pdf 
 Identifier    ZNB-1981-36b-1047_n 
 Volume    36 
210Author    PeterG. Jones, Einhard Schwarzmann, GeorgeM. Sheldrick, Harald TimpeRequires cookie*
 Title    Darstellung und Struktur von Di-gold(III)bis(selenit)(diselenit), Au2(Se0 3 )2(Se 2 05) Preparation and Crystal Structure of Di-gold(III)bis(selenite) Diselenite, Au2(Se0 3 )2(Se 2 05)  
 Abstract    The compound Au 2 (Se0 3) 2 (Se 2 0s) was pre-pared from gold metal and seienic acid at 553 K. The crystal structure [C2/c, a = 2034.4(5), b = 413.0(1), c = 1325.4(3) pm, ß = 115.88(3)°, Z = 4] was refined to R = 0.035. Both gold atoms lie on crystallographic centres of sym-metry and show square planar coordination (Au-0 196.9-201.3 pm). The extended structure consists of three cross-linked systems of the form [ • • • -Au-(selenite or diselenite) -Au----]. 
  Reference    Z. Naturforsch. 36b, 1050—1051 (1981); eingegangen am 19. Mai 1981 
  Published    1981 
  Keywords    Sealed-tube Synthesis, Crystal Structure, Selenite Ligand, Diselenite Ligand 
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 Identifier    ZNB-1981-36b-1050_n 
 Volume    36 
211Author    Ernst Guggolz, ManfredL. Ziegler, Willibald Kalcher, Johann Plank, Doris Riedel, WolfgangA. HerrmannRequires cookie*
 Title    Synthese und Molekülstruktur der dreikernigen Cluster-Verbindung (^-C5Me5)IrFea(CO)9 Synthesis and Molecular Structure of the Trinuclear Cluster Compound (^ 5 -C5Me5)IrFe2(CO)g  
 Abstract    Reaction of triirondodecacarbonyl (1) with the dinuclear chloroiridium complex [(?? 5 -C5Me5)Ir(//-Cl)Cl]2 (2) in benzene at 50 °C yields the novel mixed iron iridium cluster of composition (rj 5 -C&Mes)IrFe2(C0)9 (8) the molecular structure of which has been established by X-ray diffraction methods. The mononuclear half-sandwich complex (j7 5 -C5Me5)Ir(CO)2 (4) present in the reaction mixture was found to represent the immediate precursor of the cluster compound 8. 
  Reference    Z. Naturforsch. 36b, 1053—1059 (1981); eingegangen am 8. April 1981 
  Published    1981 
  Keywords    Iron, Iridium, Carbonyl Complexes, Pentamethylcyclopentadienyl 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-1053.pdf 
 Identifier    ZNB-1981-36b-1053 
 Volume    36 
212Author    Ernst Guggolz, Franz Oberdorfer, ManfredL. ZieglerRequires cookie*
 Title    in Gegenwart von Cyclooctatetraen und 1.3-Butadien Photochemical Reactions of Re2(CO)io in the Presence of Cyclooctatriene and 1,3-Butadiene  
 Abstract    Rhenium Carbonyl Olefin Complexes Re2(CO)io has been photolyzed in the presence of cyclooctatetraene, 1,3-butadiene and 1,4-pentadiene, respectively. In pentane solutions the species (CO)4Re-/i-(^ 3 :^ 1 -C4He)Re(CO)5, (CO)4Re-/i-(t? 2 :7] 2 -C4H6)Re(CO)4 (11) and HRe3(CO)i4 could be isolated with 1,3-butadiene. C8H8 yielded several compounds of which the following could be unequivocally charac-terized (CO)4Re-//-(r?3:^i.C8H8)Re(CO)5 (14), (^-CgHsJRefCOh-MU.S-^rö-^-CgHs)-Re(CO)4 and (CO)3Re-//-(j? 4 :77 4 -C8H8)Re(CO)3.11 and 14 have been characterized by X-ray structure analysis. 
  Reference    Z. Naturforsch. 36b, 1060—1068 (1981); eingegangen am 22. Juni 1981 
  Published    1981 
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 Identifier    ZNB-1981-36b-1060 
 Volume    36 
213Author    Alois Haas, Reiner HitzeRequires cookie*
 Title    Darstellung und Charakterisierung von Cyclotri(silaselan) (H2Si-Se)3 Preparation and Characterisation of Cyclotri(silaselane) (H2Si-Se)3  
 Abstract    Cyclotri (silaselane), Polymerisation In benzene HgSe reacts with H2SÜ2 at 120 °C to yield a polymer, which on heating in benzene depolimerizes to form (H2SiSe)3. 1 H, 29 Si, 77 Se, NMR, IR and MS data are presented. 
  Reference    Z. Naturforsch. 36b, 1069—1070 (1981); eingegangen am 18. Mai 1981 
  Published    1981 
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 Identifier    ZNB-1981-36b-1069 
 Volume    36 
214Author    Werner Storzer, Dietmar Schomburg, Gerd-Volker RöschenthalerRequires cookie*
 Title    Darstellung von 2-Amino-1.3.2;> 3 (A 5 )-dioxaphospholanen Synthesis of 2-Amino-1,3,2A 3 (A 5 )-dioxaphospholanes  
 Abstract    2-Amino-4,4,5,5-tetrakis(trifluoromethyl)-1,3,2 A 3 (A 5)-dioxaphospholanes, Oxidative Addition, Dilithiumperfluoropinacolate 
  Reference    Z. Naturforsch. 36b, 1071—1079 (1981); eingegangen am 29. Mai 1981 
  Published    1981 
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 Identifier    ZNB-1981-36b-1071 
 Volume    36 
215Author    Gerd Becker, Angelika Münch, Hans-Jürgen WesselyRequires cookie*
 Title    Acyl-und Alkylidenarsane, V [1] (Dimethylaminomethyliden)-phenylar8an, ein acyclisches Alkylidenarsan Acyl-and Alkylidenearsines, V [1] (Dimethylaminomethylidene)-phenylarsine, an Acyclic Alkylidenearsine  
 Abstract    Alkylidenearsines, Aminomethylidenearsines, Barrier of Rotation In the absence of a catalyst phenyl-bis(trimethylsilyl)arsine (1 a) reacts only very slowly with excess dimethylformamide (4) to give (dimethylaminomethylidene)-phenylarsine (8 a) and hexamethyldisiloxane (5). In the presence of small amounts of solid sodium hydroxide, however, the reaction is already finished after four days at + 20 °C. Similarly, lithium phenyltrimethylsilylarsenide • DME (2a), which can easily be obtained from la and methyllithium in 1,2-dimethoxyethane (DME), and dimethylformamide (4) also form the alkylidenearsine (3 a) and lithium trimethylsilanolate. The NMR spectra of 3 a show the rotation of the dimethylamino group to be hindered with a barrier of about 63 kJ • mol -1 . 
  Reference    Z. Naturforsch. 36b, 1080—1084 (1981); eingegangen am 7. April 1981 
  Published    1981 
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 Identifier    ZNB-1981-36b-1080 
 Volume    36 
216Author    Requires cookie*
 Title    \s = C  
 Abstract    \ H • (CH 3) 3 Si-0-Li U) N(CH 3) 2 c5H5 \ /\ / (CH3)2N As NICH3)2 C 6 H 5 (3) 6a 3a DME = 1.2-Dimethoxyethan Das ebenfalls gebildete Lithium-trimethylsilanolat (7) wird durch Zugabe von Chlortrimethylsilan zu Hexamethyldisiloxan (5) umgesetzt. Nach Filtration und destillativer Aufarbeitung isoliert man 3 a mit 85-proz. Ausbeute. Wie bei der vorherigen Um-setzung kann auch hier das Dimere 6 a nicht mehr nachgewiesen werden. Die von Oehme und Mitarb. beschriebene Darstellung des (Dimethylamino-methyliden)-phenylphosphans aus Phenylphosphan und dem Dimethylacetal des Dimethylformamids [25] konnte auf Phenylarsan bisher nicht übertragen werden. Beim Vermischen der Komponenten bildet sich eine kristalline Verbindung, deren Konstitution noch aufgeklärt werden muß. 
  Reference    Z. Naturforsch. 36b, 1081 (1981) 
  Published    1981 
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 Identifier    ZNB-1981-36b-1081 
 Volume    36 
217Author    Ralf Steudel, Eva-Maria StraussRequires cookie*
 Title    Nachweis von Se6, Se7 und Se8 in Lösungen yon Selen mittels Hochdruckflüssigkeitschromatographie Detection, of See, Se7 and Ses in Selenium Solutions by High-Pressure Liquid Chromatography  
 Abstract    Dissolution of crystalline Ses or extraction of glassy or red amorphous selenium, prepared from aqueous Se02 by reduction, by organic solvents yields solutions containing Se6, Se7 and Ses in equilibrium as shown by HPLC. The equilibrium explains the concen-tration dependence of the molar absorbance of such solutions observed earlier. Since the Raman spectrum of red amorphous selenium does not show any lines due to See, Se7 and Ses, a rapid interconversion of selenium molecules in solution at 20 °C is postulated. Red amorphous selenium may consist of a mixture of small and medium sized ring molecules. 
  Reference    Z. Naturforsch. 36b, 1085—1088 (1981); eingegangen am 23. Juni 1981 
  Published    1981 
  Keywords    Elemental Selenium, Equilibrium in Solution, HPLC, Amorphous Selenium 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-1085.pdf 
 Identifier    ZNB-1981-36b-1085 
 Volume    36 
218Author    J. Markopoulos, D. JannakoudakisRequires cookie*
 Title    Über die inhibierende Wirkung grenzflächenaktiver Stoffe auf die polarographische Reduktion von Cd 2+ -, Zn 2+ -und Co 2+ -Ionen in wasser-methanolischen und methanolischen Lösungen On the Inhibition Effect of Surfactants on the Polarographic Reduction of Cd 2+ , Zn 2+ and Co 2+ Ions in Aqueous Methanolic and Methanolic Solutions  
 Abstract    The inhibition effect of tri-n-octylphosphine oxide (TOPO), triphenylarsine oxide (TAsO), triphenylphosphine oxide (TPO), triphenylarsine (TPAs) and triphenylphosphine (TPP) on the polarographic reduction of Cd 2+ , Zn 2+ and Co 2+ ions in aqueous methanolic and methanolic solutions has been studied. 
  Reference    Z. Naturforsch. 36b, 1089—1092 (1981); eingegangen am 18. Mai 1981 
  Published    1981 
  Keywords    Polarography, Inhibitors, Electroreduction, Triphenylarsine Oxide 
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 Identifier    ZNB-1981-36b-1089 
 Volume    36 
219Author    Rüdiger Mews, Peter Kricke, Ingo StahlRequires cookie*
 Title    Schwefel(VI)-oxid-chlorid-imide und Schwefel(VI)-oxid-fluorid-imide [1] Sulfur(VI)-oxide-chloride-imides and Sulfur(VI)-oxide-fluoride-imides [1]  
 Abstract    At room temperature in the presence of CsF sulfur-oxide-chloride-fluoride-imides RfNSOFCl (8) (Rf = CF3, C2F5, t-C3F7, C6F5) are formed from N-perfluoroalkyl-sulfinyl-imides and Cl2. At prolonged reaction times or higher temperatures the chloride is ex-changed and the difluorides RfNSOF2 are isolated in high yields. In the same way (CF3)2CFNS(0)C1CF3 (12) and (CF3)2CC1NS(0)C1CF3 (13) are obtained from (CF3)2C = N-S(0)CF3 (9) and Cl2/CsF. 12 can be fluorinated by CsF to give (CF3)2CFNS(0)FCF3 (14). 14 is also observed, when fluorine is added to 9 via XeF2 in the presence of BF3, but mainly C-S-bond cleavage occurs. SF5NS(0)FCF(CF3)2 (19) was identified by spectroscopic methods from the reaction of SFsNSOF2 and CF3CF = CF2 in the presence of CsF. 
  Reference    Z. Naturforsch. 36b, 1093—1098 (1981); eingegangen am 19. Juni 1981 
  Published    1981 
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 Identifier    ZNB-1981-36b-1093 
 Volume    36 
220Author    Erwin Brechtel, Gerhard Cordier, Herbert SchäferRequires cookie*
 Title    Neue Verbindungen mit der CagMi^Big-Struktur: Zur Kenntnis von Ca^djBi^ Sr9Cd4Bi9 und Ca9Zn4Sb9 New Compounds with the CagMr^Bi» Structure: CagCcUBig, SrgCcUBig, and CagZniSbg  
 Abstract    Intermetallic Phases, Crystal Structure The new compounds CagCcLjBig, SrgCcLjBig and CagZnjSbg crystallize in the ortho-rhombic system (Pbam) in the CagMrnBig structure with the following constants: 
  Reference    Z. Naturforsch. 36b, 1099—1104 (1981); eingegangen am 19. Juni 1981 
  Published    1981 
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 Identifier    ZNB-1981-36b-1099 
 Volume    36 
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