Browsing by Author "Zuluaga, Fabio"
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Item (E)-5-[1-Hydroxy-3-(3,4,5-trimethoxyphenyl)allylidene]-1,3-dimethylpyrimidine-2,4,6-trione: Crystal structure and Hirshfeld surface analysis(International Union of Crystallography, 2017-07-13) Soto-Monsalve, Mónica; Romero, Elkin L.; Zuluaga, Fabio; Chaur, Manuel N.; D'Vries, Richard F.In the title compound, C18H20N2O7, the dihedral angle between the aromatic rings is 7.28 (7)° and the almost planar conformation of the molecule is supported by an intramolecular O - H⋯O hydrogen bond, which closes an S(6) ring. In the crystal, weak C - H⋯O hydrogen bonds and aromatic π-π stacking link the molecules into a three-dimensional network. A Hirshfeld surface analysis showed that the major contribution to the intermolecular interactions are van der Waals interactions (H⋯H contacts), accounting for 48.4% of the surface. © Soto-Monsalve et al. 2017.Item (E)-5-[1-Hydroxy-3-(3,4,5-trimethoxyphenyl)allylidene]-1,3-dimethylpyrimidine-2,4,6-trione: crystal structure and Hirshfeld surface analysis(Acta Crystallographica Section E: Structure Reports Online, 2017) Soto-Monsalve, Mónica; Romero, Elkin L.; Zuluaga, Fabio; Chaur, Manuel N.; D’Vries, Richard F.In the title compound, C 18 H 20 N 2 O 7 , the dihedral angle between the aromatic rings is 7.28 (7)° and the almost planar conformation of the molecule is supported by an intramolecular O—H...O hydrogen bond, which closes an S (6) ring. In the crystal, weak C—H...O hydrogen bonds and aromatic π–π stacking link the molecules into a three-dimensional network. A Hirshfeld surface analysis showed that the major contribution to the intermolecular interactions are van der Waals interactions (H...H contacts), accounting for 48.4% of the surface.Item New pyrazolino and pyrrolidino[60]fullerenes: the introduction of the hydrazone moiety for the formation of metal complexes(Journal of Physical Organic Chemistry, 2016) Romero, Elkin L.; Cabrera-Espinoza, Andrea; Ortiz-Peña, Nathaly; Soto-Monsalve, Mónica; Zuluaga, Fabio; D’Vries, Richard F.; Chaur, Manuel N.The [3 + 2] cycloaddition reaction of C60 with pyridine-derived hydrazones (acting as dipolar reagents) was successfully conducted resulting in fullerene derivatives 5a, 5b. The compounds were characterized by means of NMR, UV–Vis spectroscopy, and X-ray crystallography. The electrochemical behavior was also investigated. The fulleropyrazoline 5a exhibits anodically shifted reduction potentials of about 100 mV when compared with those for C60, whereas 5b exhibits cathodic shifts relative to pristine C60. The complexation reaction of 5b with metallic ions (Zn2+, Cd2+, and Fe2+) was achieved. Job and Benesi–Hildebrand analysis confirmed the formation of complexes with a molar ratio of 1:1 and binding constants between 2.26 × 105 and 1.59 × 105 M−1. Electrochemistry of these complexes showed a marked influence of the metal ion on the reduction potentials.Item Structural characterization of a fluorescein hydrazone molecular switch with application towards logic gates(New Journal of Chemistry, 2018) Villada, Juan D.; D’Vries, Richard F.; Macías, Mario; Zuluaga, Fabio; Chaur, Manuel N.A fluorescein acylhydrazone (2) as well as its metal complexes with Zn2+, Ni2+ and Cu2+ ions were synthesized and characterized by means of NMR (1H, 13C and 2D experiments), UV-Vis, fluorescence spectroscopy, FT-IR and single crystal X-Ray diffraction. The compound crystallizes in Pī triclinic space group, with two fluorescein acylhydrazone (2) conformers and one water molecule per symmetric unit. The fluorescein acylhydrazone (2) and metal derivates were analysed by cyclic voltammetry, finding a relation between the shifting in their redox potential with the quenching of fluorescence. Emission and UV-Vis absorption logic gates were fabricated based on the metal ion binding of 2 and its behaviour at different pH values. Compound 2 exhibited “on-off” behaviour in the fluorescence emission with the addition of triethylamine (TEA) this effect is highly enhanced by the joint addition of Zn2+. Conversely, the fluorescence is highly quenched by the addition of trifluoroacetic acid (TFA) or Ni2+ ions allowing to fabricate a AND gate using TEA and Zn2+ as inputs, and a INHIBIT gate with the addition of TFA or Ni2+, both using the fluorescence emission as outputs. The addition of Cu2+ resulted in a fluorescence emission at 525 nm that is red shifted with the addition of TEA. This behaviour allowed us to construct a XOR gate with the fluorescence emission at 525 nm as output, and the addition of Cu2+ and TEA as inputs. The absorption in the visible region was used to create AND gates with the addition of Cu2+ ions and TEA, or Ni2+and TEA as inputs. The INH, AND, XOR gates were manipulated by the controlled addition of different metal cations, TEA and TFA as inputs, and fluorescence emission and visible absorption as outputs allowing us to create three different combinatorial circuits in which we want to highlight a new molecular “HALF-ADDER”.Item Structural, spectroscopic, and theoretical analysis of a molecular system based on 2-((2-(4- chlorophenylhydrazone)methyl)quinolone(Universidad Nacional de Colombia, 2018-12-02) Romero, Elkin L.; Soto-Monsalve, Mónica; Gutiérrez, Gustavo; Zuluaga, Fabio; D'Vries, Richard F.; Chaur, Manuel N.A novel molecular system based on 2-((2-(4-chlorophenylhydrazone)methyl)quinoline (1-E) was synthesized. Interconversion of 1-E to its configurational isomer 1-Z was achieved using UV radiation (250 W Hg lamp). Such isomerization was monitored by1H-NMR. The results suggest that the hydrazone derivative can act as a chemical brake in solution. This molecular system was structurally (Single Crystal X-Ray diffraction and DFT calculations) and spectroscopically (NMR, UV, and IR) characterized. Electrochemical measurements showed that configurational changes induce differential redox behavior. In this regard, the reported quinoline system exhibits different dynamic absorption and electrochemical properties that are modulated by UV-light. Therefore, 1-E can be regarded as a potential photo-electrochemical switch. © 2018, Universidad Nacional de Colombia. All rights reserved.