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1983 (1)
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1Author    Moisés Morán, Augusto Ibáñez, J. R. MasaguerRequires cookie*
 Title    Reactions of r/-C5H5Co(CO)2 and ^-Me3SiC5H4Co(CO)2 with (XCN)2 and X(CN)2 (X = S or Se)  
 Abstract    The pseudohalogens (XCN) 2 (X = S or Se) react with ^-C5H 5 Co(CO)2 and 7;-Me3SiC5H4Co(CO)2 with formation of the 18 electron complexes, RCo(CO)(XCN)2 (R = r]-C5H5 or ^-MeßSiCsBU). By reactions with X(CN)2 (X = S or Se), the cyclopentadienyl cobalt dicarbonyls are transformed into the mixed complexes, RCo(CO)(CN)(XVN) (R = ^-CÖHÖ or ^-MesSiCsH^. All the compounds are characterized by elemental analysis, IR, electronic and 1 H NMR spectra. The thiocyanogen derivatives undergo linkage isomerism (N->S) in polar solvents. 
  Reference    Z. Naturforsch. 37b, 292—298 (1982); received September 21/November 9 1981 
  Published    1982 
  Keywords    Pseudohalogens, Electron Complexes, 1 H NMR Spectra 
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 TEI-XML for    default:Reihe_B/37/ZNB-1982-37b-0292.pdf 
 Identifier    ZNB-1982-37b-0292 
 Volume    37 
2Author    Jochen Eilermann, Martin LietzRequires cookie*
 Title    Chemie polyfunktioneller Liganden, 60 [1] Über Käfigverbindungen mit den Heteroelementen Arsen und Selen Chemistry of Polyfunctional Ligands, 60 [1] On Cage Compounds with the Heteroelements Arsenic and Selenium  
 Abstract    The reaction of l,l,l-tris(diiodoarsinomethyl)ethane, CH3C(CH2Asl2)3 (1) with NaAs(CeH5)2 in the molar ratio of 1:3 gives 4-methyl-l,2,6-triarsa-tricyclo[2,2,l,0 2 -6 ]-heptane, CH3C(CH2As)3 (2). The previously synthesized CH3C(CH2AsS)3 (4) can be de-sulphurated with triphenylphosphine to yield also 2. The reaction of 1 with NaSeH gives the new cage compound 6-methyl-l,3,4-triarsa-2,8-diselena-tricyclo[3,3,l,0 3 > 4 ]-nonane, CH3C(CH2As)3Se2 (5). 
  Reference    Z. Naturforsch. 35b, 1514—1517 (1980); eingegangen am 5. August 1980 
  Published    1980 
  Keywords    Hetero Cage Compounds, Synthesis, Vibrational Spectra, Mass Spectra, 1 H NMR Spectra 
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 TEI-XML for    default:Reihe_B/35/ZNB-1980-35b-1514.pdf 
 Identifier    ZNB-1980-35b-1514 
 Volume    35 
3Author    Helmut Stamm, Jürgen StafeRequires cookie*
 Title    Molecular Complexes, V [1, 2] X H NMR Investigation of the Caffeine Benzene Complex Followed by AUS Correction of Experimental Data Structural Requirements for Substances to Serve as Internal Reference in Investigations of Weak Complexes  
 Abstract    The 4 proton signals of caffeine, dissolved in carbon tetrachloride, were investigated as functions of benzene concentrations in a very large concentration range. Shifts of the 4 signals were measured relative to both internal and external reference. Scatchard plots of the internally referenced data were curved downwards, the degree of curving increasing from 7-methyl/8-H to 3-methyl to 1-methyl. The 1-methyl plot even showed a maximum in the observed relative shifts zJ 0 i which turned to negative values for high benzene concentrations. Scatchard plots of the externally referenced data were curved upwards. Applying AUS corrections [1, 8] to both sets of data furnished linear Scatchard plots for ah signals. The plots for the 4 protons were parallel to one another in case of the externally referenced data and not parallel for the internally referenced data. Equilibrium quotients K calculated from the externally referenced data for each of the 4 different protons were essentially the same. This gives evidence that the system behaves in accord with the pure 1:1 complex model and does not demand the assumption of simultaneous occurence of higher complexes. The values for K (— .1151/mol), for the 4 apparent complex shifts (Icpt/K) and for the 4 nuclei specific AUS coefficients a 2 [1, 8] could be confirmed and somewhat improved by a Creswell-Allred processing of the data including AUS correction. The failure of the AUS correction in producing parallel Scatchard plots from internally referenced shifts is caused by the nonlinear floating with the donor concentration of the internal reference signal. The cause of this nonlinear behaviour is analyzed, and arguments are presented that it can be prevented by use of reference substances with only one single reference group per molecule, i.e. the signal of such an internal reference must not have its origin in two or more equivalent nuclei groups within the reference molecule. 
  Reference    Z. Naturforsch. 36b, 1618—1627 (1981); received July 1 1981 
  Published    1981 
  Keywords    Nucleus Independent 1:1 Formation Constant, Benzene Induced Shifts, 1 H NMR Spectra, Caffein Benzene Complex 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-1618.pdf 
 Identifier    ZNB-1981-36b-1618 
 Volume    36 
4Author    Jürgen Schallenberg, Eckart MeyerRequires cookie*
 Title    Simple Syntheses of 3-Substituted Indoles and their Application for High Yield 14 C-Labelling  
 Abstract    Methods are described which allow the synthesis of several plant indole alkaloids and their metabolites at different scales. Compounds synthesized include gramine (1) (3-di-methylaminomethylindole) which is directly derived from indole, while its biosynthetic precursors 3-aminomethylindole (3) and 3-methylaminomethylindole (2) as well as indole-3-carboxylic acid (7) are synthesized via indole-3-aldehyde (6). Slight changes of the experimental conditions allow syntheses with high yields not only at the molar but also at the /imolar level. This is extremely useful when isotope labelled compounds of high specific radioactivity are required for studies of plant metabolism. 
  Reference    (Z. Naturforsch. 38b, 108—112 [1983]; received July 22 1982) 
  Published    1983 
  Keywords    3-Substituted Indoles, Indole Alkaloids, UV Spectra, MS Spectra, 1 H NMR spectra 
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 TEI-XML for    default:Reihe_B/38/ZNB-1983-38b-0108.pdf 
 Identifier    ZNB-1983-38b-0108 
 Volume    38