Browsing by Author "Bunel Torrealba, Sergio"
Now showing items 1-20 of 21
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Bunel Torrealba, Sergio; Ibarra, C.; Adan, L. (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 by oxygen atoms of water or of carboxylic groups is analyzed in terms of ...
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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 ...
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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 ...
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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 ...
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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.
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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Parada Aliste, José; Bunel Torrealba, 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 ...
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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 ...
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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 ...
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Gil, L.; Moraga, E.; Bobadilla, H.; Bunel Torrealba, Sergio; Bunton, C. A. (1975)Study of the visible absorption and circular dichroism spectra of mixed complexes formed by copper(II), an optically active amino acid anion and a phenanthroline or dipyridyl moiety, shows that although the absorption ...
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Bunel Torrealba, Sergio; Ibarra, Carmen; Calvo Pérez, Víctor; Moraga, Exequiel (PERGAMON-ELSEVIER SCIENCE LTD, 1989)
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Bunel Torrealba, Sergio; Ibarra, Carmen; Rodríguez, M.; Urbina, A.; Bunton, Clifford A. (Pergamon Press, 1981)Complexes of Cu(II) with L-aminoacids have positive charge transfer bands in their CD spectra at ca.230 nm and negative at ca. 270 nm. Examination of complexes with L-1,2-diamino propane shows that the positive band is ...
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Schirado, T.; Gennari, E.; Merello, R.; Decinti, A.; Bunel Torrealba, Sergio (1971)A comparative study of the ligand reactivity at the 3-position in trisacetylacetonates of Cr(III) and Co(III), by means of nitration and Vilsmeier-Haack reactions, was attempted. The sequence Co > Cr in both reactions ...
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Larrazábal Rojas, Guillermo; Bunel Torrealba, Sergio; Ibarra, Carmen; Parada Aliste, José (2002)Reaction between cis-[Co(NH3)(H2O)(2)](3-) and ammonia in aqueous solution, in the presence of a carbohydrate, leads to the formation of the tetranuclear complex of cobalt (III): [Co-4(NH3)(12)(OH)(6)](6+) partially resolved. ...
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Bunel Torrealba, Sergio; Ibarra, Carmen; Moraga, Exequiel; Blasko, Andrei; Bunton, Clifford A. (Elsevier Science Publishers B.V., 1993)The 1H NMR signals of the hydrochlorides of 2-amino-2-deoxy-α and β -D-Glucose (α-and β-D-glucosamine) have been assigned and chemical shifts and coupling constants determined from their phase-sensitive COSY spectra in ...
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Bunel Torrealba, Sergio; Ibarra, Carmen; Rodríguez, M.; Urbina, A.; Bunton, Clifford A. (Pergamon Press Ltd., 1981)