Now showing items 1-20 of 28

    • Band shift in chromium(III) complexes with mixed ligands: molecular orbital approach 

      Bunel Torrealba, Sergio; Ibarra, Carmen; Adán, L. (Pergamon Press, 1969)
      The shift of the first and second spin allowed bands due to the stepwise replacement of the nitrogen atoms in a complex of Cr(III) of the CrN6 type of oxigen atoms of water or of carboxylic groups is analized in terms of ...
    • Charge transfer circular dichroism of complexes of copper(II) with aminoacids and heterocyclic ligands 

      Bunel Torrealba, Sergio; Ibarra, Carmen; Bunton, Clifford A. (Pergamon Press, 1975)
      In the u.v. region the C.D. spectra of mixed complexes of Cu(II), aminoacids and heterocyclic ligands depend upon the nature of the heterocyclic ligand, and work on the Cotton effects of bis-Ł-aminoacidates of cu(II) in ...
    • Complessi del Cu con diammine alifatiche a lunga catena 

      Caglioti, V.; Furlani, C.; Dessy, G.; Ibarra, Carmen (Societá Chimica Italiana, 1962)
      Sono stati preparati diversi tipi di complessi del rame con diammine alifatiche a lunga catena di atomi di C, correpondenti alle formule: CuCl2.1/2 am (giallo), CuCl2.am (verde) e CuCl2.am(azzurro o viola), dove am = ...
    • Complexation of amino sugars with cobalt(III) bis (phenanthroline) 

      Bunel Torrealba, Sergio; Ibarra, Carmen; Moraga, Exequiel; Parada Aliste, José; Blasko, Andrei; Whiddon, Christy; Bunton, Clifford A. (Elsevier, 1998)
      The I3- salts soluble in acetone and sparingly so in methanol, and I3- inhibits formation of Co(II) so that minor decomposition of acomplex does not broaden its 1H NMR signals. The (phen)2 complex of Co(III) with D-glucosamine ...
    • Complexation of mannosamine with cobalt(III) bis-phenanthroline. Isolation of a stable triiodide salt 

      Bunel Torrealba, Sergio; Ibarra, Carmen; Moraga, Exequiel; Parada Aliste, José; Blasko, Andrei; Bunton, Clifford A. (Sociedad Chilena de Química, 1997)
      D-β-Mannosamine reacts with cobalt(III) bis-phenanthroline to form a single 1:1 complex with the ∆ configuration at Co(III) which can be isolated as the stable triiodide salt.
    • Complexation of sucrose with cobalt(III)bis(phenanthroline) 

      Parada Aliste, José; Bunel Torrealba, Sergio; Ibarra, Carmen; Larrazábal Rojas, Guillermo; Moraga, Exequiel; Gillitt, N. D.; Bunton, Clifford A. (ELSEVIER SCI LTD, 2000-10-20)
      The Delta-[Co(III)bis(phenanthroline)(sucrose)](3+) complex forms with little perturbation of the sucrose conformation, and complexation by HO-2(g) and HO-1(f).
    • Complexes of Co(III) with L-sorbose and phenanthroline 

      Blasko, Andrei; Bunton, Clifford A.; Moraga, Exequiel; Bunel Torrealba, Sergio; Ibarra, Carmen (ELSEVIER SCIENCE BV, 1995-12-20)
      L-Sorbose and two molecules of 1,10-phenanthroline form a complex with Co(III) which has the Lambda configuration about Co(III), based on CD and ORD spectra, The H-1 NMR signals of alpha-L-sorbopyranose and its mixed ...
    • COMPLEXES OF COBALT(III) WITH D-FRUCTOSE AND PHENANTHROLINE 

      Moraga, Exequiel; Bunel Torrealba, Sergio; Ibarra, Carmen; Blasko, Andrei; Bunton, Clifford A. (ELSEVIER SCIENCE BV, 1995-03-01)
      D-Fructose and 1,10-phenanthroline form complexes with Co(III). Configurations about Co(III) are assigned from the CD and ORD spectra of the separated Lambda and Delta diastereomers, and Lambda strongly predominates in the ...
    • COMPLEXES OF COBALT(III) WITH D-GLUCOSAMINE AND AMINES 

      Bunel Torrealba, Sergio; Ibarra, Carmen; Moraga, Exequiel; Calvo Pérez, Víctor; Blasko, Andrei; Bunton, Clifford A. (ELSEVIER SCIENCE BV, 1993-02-01)
      D-Glucosamine and ammonia, 1,2-ethylenediamine, or 1,10-phenanthroline form complexes with Co(III)*. The complexes are: [Co(NH3)3-H2O-D-glucosamine]3+, [Co(en)2.D-glucosamine]2+ and [Co(phen)2.D-glucosamine]3+. Formation ...
    • Determination of acid dissociation constants of anomers of amino sugars by 1H NMR spectroscopy 

      Blasko, Andrei; Bunton, Clifford A.; Bunel Torrealba, Sergio; Ibarra, Carmen; Moraga, Exequiel (Elsevier Science Publishers B. V., 1997)
      Acid dissociation constants of α- and β-D-glucos-, mannos-, and galactos-ammonium ions have been determined from 1H NMR chemical shifts of the individual anomers in D2O. Values of pKa(D) for the α- and β-ammonium ions ...
    • Formation and structure of a complex of sucrose with cobalt(III)bis(phenanthroline) 

      Parada Aliste, José; Bunel Torrealba, Sergio; Ibarra, Carmen; Larrazábal Rojas, Guillermo; Moraga, Exequiel; Gillitt, N. D.; Bunton, Clifford A. (ELSEVIER SCI LTD, THE BOULEVARD, 2001-07-12)
      Sucrose forms a dicationic complex with cobalt(III)bis(phenanthroline) which can be isolated as the sparingly water-soluble triiodide salt or the water-soluble chloride. The circular dichroism (CD) spectrum demonstrates ...
    • Induced distant cotton effects in an aromatic chromophore in mixed aminoacides of copper(II) 

      Bunel Torrealba, Sergio; Ibarra, Carmen; Urbina, A.; Bunton, Clifford A. (Pergamon Press, 1977)
      Chiral amino acids bonded to copper(II) induce Cotton effects in the visible and UV regions corresponding tod-d and charge transfer transitions [1,2] but and induced Cotton effect on a distant ligand has not been observed ...
    • Induced distant cotton effects in mixed Cu(II) complexes of amino and hydroxy acids and heterocyclic ligands 

      Bunel Torrealba, Sergio; Ibarra, Carmen; Rodríguez, M.; Urbina, A.; Bunton, Clifford A. (Pergamon Press Ltd., 1981)
      Mixed 1:1:1 complexes of proline or aspartic acid with Cu(II) and 9:10-phenanthroline (phen) or 2,2'bipyridine (bipy) show induced Cotton effects in the aromatic region. The effect is ascribed to interactionsbetween the ...
    • Isolation and characterization of cobalt (III) tris-D-aminosugars 

      Parada Aliste, José; Larrazábal Rojas, Guillermo; Mendoza, Jorge; Cañón, Walter; Ibarra, Carmen (SOCIEDAD CHILENA DE QUIMICA, 2006-06)
      Mixed complexes of animosugars and 1,10-phenanthroline (phen) with cobalt(III), with the composition Co(III)(phen)(2)sugar, disproportionate in aqueous solution in approximately one month, giving non ionic tris-aminosugar ...
    • Mixed complexes of cobalt(III) with D-glucosamine and phenanthroline 

      Blasko, Andrei; Bunton, Clifford A.; Bunel Torrealba, Sergio; Moraga, Exequiel; Ibarra, Carmen; Parada Aliste, José (Sociedad Chilena de Química, 1995)
      Examination of 1H chemical shifts of a complex of D-glucosamine with bis-phenanthroline cobalt(III)shows that the dominant ∆-complex is formed from α-D-glucosamine. A molecular mechanics simulation of the structure of ...
    • Mixed complexes of cobalt(III) with phenanthroline and galactose or arabinose 

      Parada, José; Bunel, Sergio; Moraga, Exequiel; Ibarra, Carmen; Gillitt, Nicholas D.; Bunton, Clifford A. (2001)
      Mixed complexes of bis-phenanthroline cobalt(III) and α-D-galactose or β-D- or L-arabinose are identified in aqueous solution from their 1H NMR and circular dichroism (CD) spectra. Galactose forms only the Δ-complex, but ...
    • Optical activity of Co(III) ammine complexes and chiral ligands. Circular dichroism spectra of some CoN3O3 and CoN4O4O2 chromophores 

      Bunel Torrealba, Sergio; Ibarra, Carmen; Calvo Pérez, Víctor; Larrea, L. (Sociedad Chilena de Química, 1990)
      A partir de complejos amoniacales de Co(III) se sintetizaron compuestos que contienen los ligantes quirales L-aspartato y L-malato como segundo ligante. Los compuestos se identificaron por medio de análisis, mediciones de ...
    • Optical activity of compounds formed by amino-complexes of Co(III) and carbohydrates-I 

      Bunel Torrealba, Sergio; Ibarra, Carmen (Pergamon Press, 1985)
      The preparation of aminocomplexes of Co(III) containing D-ribose, L-sorbose or D-glucosamine as second ligand is described. Their spectral features and optical activity are reported. Formation in solution of complex ...
    • Optical activity of nickel(II) and copper(II) complexes with L-aminoacids in the UV spectral region 

      Ibarra, Carmen; Soto, R.; Adán, L.; Decinti Weiss, Emilio; Bunel Torrealba, Sergio (Elsevier Sequoia, 1972)
      Complexes of Cu(II) and Ni(II) with L-aminoacids have been prepared and their UV spectra and optical activity studied. The results are interpreted in terms of the conformation of the chelated rings. A molecular orbital ...
    • OPTICAL-ACTIVITY OF COMPOUNDS FORMED BY AMMINO COMPLEXES OF COBALT(III) AND CARBOHYDRATES .2. D-ARABINOSE COMPLEXES 

      Bunel Torrealba, Sergio; Ibarra, Carmen; Calvo Pérez, Víctor; Moraga, Exequiel (PERGAMON-ELSEVIER SCIENCE LTD, 1989)