Now showing items 1-20 of 25

    • Castañeda Magliona, Fernando; Aliaga Silva, Christian Marcelo; Bunton, Clifford A.; Garland, María Teresa; Baggio, Ricardo (BLACKWELL PUBLISHING, 2005-08)
      The title ylides, 3-(triphenylphosphoranylidene) pentane-2,4-dione, C23H21O2P, (I), and diethyl 2-(triphenylphosphoranylidene)malonate, C25H25O4P, (II), differ in the conformations adopted by their extended ylide moieties. ...
    • 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 ...
    • 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 ...
    • 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).
    • 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 ...
    • 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 ...
    • 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 ...
    • Castañeda Magliona, Fernando; Recabarren Gajardo, Gonzalo Iván; Hu, J.; Gillitt, N. D.; Bunton, Clifford A. (TAYLOR & FRANCIS LTD, 2003-11)
      The diacyl ylide, 3-triphenylphosphoranylidene-2,4-pentanedione (2) can adopt conformations stabilized by ylidic resonance with both acyl oxygens syn- or with one oxygen syn- and the other anti- to cationoid phosphorus, ...
    • Castañeda Magliona, Fernando; Aliaga Silva, Christian Marcelo; Garland, María Teresa; Hu, J.; Gillitt, N. D.; Bunton, Clifford A. (TAYLOR & FRANCIS LTD, 2007-01)
      The diacyl ylid, 3-triphenylphosphoranylidene-2,4-pentanedione 2 can adopt conformations with one oxygen syn- and the other anti- to phosphorus 2a as in the crystal, or with both oxygens syn- to phosphorus 2b. In solution, ...
    • Castañeda Magliona, Fernando; Acuña, C.; Garland, María Teresa; Gillitt, N. D.; Shirazi, A.; Yunes, S. J.; Bunton, Clifford A. (TAYLOR & FRANCIS LTD, 2007)
      The mixed stabilized triphenyl phosphonium ylides Ph3P= C(CN)CO-R and Ph3P= C(CN)COOR, R= CH3, C2H5, CH(CH3)(2), 1a, c and 2a, b, respectively, have sharp H-1 and C-13 NMR signals, except for 2b in some conditions. Ab ...
    • Castañeda Magliona, Fernando; Bunton, Clifford A.; Baggio, Ricardo; Garland, María Teresa (BLACKWELL PUBLISHING, 2007-01)
      Crystalline cyano-stabilized triphenylphosphonium ylids with keto or ester groups give rise to an extended electronic delocalization. In methyl 2-cyano-2-(trimethylphosphonio)-ethenoate, Ph3P=C(CN)CO2CH3 or C22H18NO2P, ...
    • 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 ...
    • Castañeda Magliona, Fernando; Jullian Matthaei, Carolina; Bunton, Clifford A.; Garland, María Teresa; Baggio, Ricardo (International Union of Crystallography, 2007)
      Hydrogen bonding and crystal packing play major roles in determining the conformations of ethyl methyl 2-(triphenyl-phosphoranylidene)malonate, Ph3P=C(C02CH3)CO2CH2CH3 or C24H23O4P,(I), and dimethyl 2-(triphenylphosphora ...
    • Castañeda Magliona, Fernando; Silva, Paul; Bunton, Clifford A.; Garland, María Teresa; Baggio, Ricardo (BLACKWELL PUBLISHING, 2008-07)
      The conformations of organic compounds determined in the solid state are important because they can be compared with those in solution and/or from theoretical calculations. In this work, the crystal and molecular structures ...
    • 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 ...
    • 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 ...
    • 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 ...
    • Castañeda Magliona, Fernando; Terraza, C. A.; Garland, María Teresa; Bunton, Clifford A.; Baggio, Ricardo (MUNKSGAARD INT PUBL LTD, 2001-02)
      The crystal structures of four alkyl 3-oxo-2-(triphenylphosphoranylidene)butyrates, where the alkyl group is methyl (C23H21O3P .0.5C(6)H(6)), (II), ethyl (C24H23O3P), (III), isopropyl (C25H25O3P), (IV), or tert-butyl ...
    • 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 ...
    • 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 ...