Browsing by Autor "John Hurtado"

Now showing 1 - 8 of 8

Antifungal activity of Co(II) and Cu(II) complexes containing 1,3-bis(benzotriazol-1-yl)-propan-2-ol on the growth, virulence traits of fluconazole-resistant Candida: Synthesis, DFT calculations and biological activity
(Research Square (United States), 2022) Ricardo A. Murcia-Galán; Sandra M. Durán; Sandra Milena Leal Pinto; Martha V. Roa; José D. Vargas; Laura V. Herrera; Alvaro Muñoz‐Castro; Desmond MacLeod‐Carey; Tonny W. Naranjo; John Hurtado
Abstract Relevant virulence traits in Candida are associated with the dimorphic change and biofilm formation, which became an important target to reduce the antifungal resistance. In this work, Co(II) complexes containing a benzotriazole derivative ligand showed a promising capacity of reduce these virulence traits. These complexes exhibited higher antifungal activities than the free ligands against all the Candida albicans and non- albicans strains tested, where compounds 2 and 4 showed minimum inhibitory concentration values between 15.62 and 125 µg mL − 1 . Moreover, four complexes ( 2 – 5 ) of Co(II) and Cu(II) with benzotriazole ligand were synthesized. These compounds were obtained as air-stable solids and characterized by melting point, thermogravimetric analysis, infrared, Raman and ultraviolet/visible spectroscopy. The analysis of the characterization data allowed to identify that all the complexes had 1:1 (M:L) stoichiometries. Additionally, Density Functional Theory calculations were carried out for 2 and 3 to propose a probable geometry of both compounds. The conformer Da of 2 was the most stable conformer according to the Energy Decomposition Analysis; while the conformers of 3 have a fluxional behavior in this analysis that didn’t allow to recognize the most probable conformer. These results provide an important platform for the design of new compounds with antifungal activities and capacity of attack other target of relevance to reduce the antimicrobial resistance.
Aromaticity introduced by antiferromagnetic ligand mediated metal–metal interactions. Insights from the induced magnetic response in [Cu6(dmPz)6(OH)6]
(Royal Society of Chemistry, 2017) Víctor Molina; Markus Rauhalahti; John Hurtado; Heike Fliegl; Dage Sundholm; Alvaro Muñoz‐Castro
Ligand-mediated antiferromagnetic coupling induces aromatic-ring behavior.
Crystal Structure and Characterization of Coordination Complexes with 2-(Tert-Butoxy)-6-(1h-Imidazol-1-Yl)Pyridine
(RELX Group (Netherlands), 2025) David Ezenarro-Salcedo; Daniela Fonseca; Sergio Alexander Patiño-Cubides; Mario A. Macías; John Hurtado
Electrochemical Characterization of Cobalt Complexes with Benzoate and Azole-Pyridine Ligands As Potential Electrolytes in Batteries
(Institute of Physics, 2025) Lina Katherine La Rotta; Daniela Fonseca; John Hurtado; María I. Montañez
The study of electroactive species with multiple redox events is of interest due to their applications as electrolytes in Redox Flow Batteries (RFBs). This multi-electron behavior can be observed in organic molecules and coordination compounds containing ligands with heteroatoms such as O and N in π-extended systems. In this context, a study of 3,5-dinitrobenzoic acid, its respective cobalt complexes (1), and azole-pyridine co-ligands (2) was conducted. Electrochemical characterization of the cobalt complexes was performed using cyclic voltammetry. Measurements were conducted in a three-electrode cell, using glassy carbon as the working electrode, Ag/AgCl as the reference electrode, and a Pt wire as the counter electrode. 1 mM solutions of the benzoate ligand, 0.6 mM of complex 1, and 0.7 mM of complex 2 were prepared in acetonitrile with 0.1 M TBAPF 6 as the supporting electrolyte. The 3,5-dinitrobenzoic acid ligand was studied in a potential window of -1.7 to 0 V. Two redox events were observed at potentials of -1.21 V and -0.79 V. Both events were quasi-reversible, with ΔE values of 88 mV and 53 mV, respectively. For complex 1, an exploratory window from -1.7 to 0 V was studied, and two quasi-reversible redox events were observed that appeared to coincide with those of the benzoate ligand. These events occurred at -1.24 V and -0.93 V. It is proposed that all these events are due to redox processes of the nitro groups present in the ligand, suggesting that cobalt may not be exhibiting redox activity. In contrast, complex 2 was studied in the potential window of 1 to 2.2 V, showing two irreversible oxidation events at around 1.73 V and 1.96 V. A decrease in peak current was observed over successive cycles, indicating a potential chemical process involving the oxidized species. To evaluate the stability of the species of interest, cyclic voltammetry over 20 cycles was performed It was observed that the 3,5-dinitrobenzoic acid ligand and its complex 1 presented more stable profiles, without significant changes in the peak currents or potentials. However, complex 2 exhibited instability because as the cycles pass, the current potentials decrease and the oxidation peaks disappear. Additionally, for the benzoate ligand and complex 1, cyclic voltammetries were carried out at different scanning speeds in order to obtain the diffusion coefficients of each species. In this order of ideas, both the 3,5-dinitrobenzoic acid ligand and complex 1 are the most suitable molecules to study their application in redox flow batteries. The benzoate ligand has the advantage of having a lower molecular weight, an important factor in energy density, but it has lower stability, while complex 1 has a higher molecular weight but provides greater stability. On the other hand, complex 2 does not present reversible redox events, which is why it is not applicable as an electrolyte in BFR. Figure 1
Electrochemical determination of paracetamol in a pharmaceutical dose by adsorptive voltammetry with a carbon paste/La2O3microcomposite
(Royal Society of Chemistry, 2020) Édgar Nagles; Mario Ceroni; John Hurtado-Murillo; John Hurtado
This paper presents a new application for microcomposites based on carbon paste (CP) and La2O3 (LaOX). This simple and versatile microcomposite (LaOX/CPE) was applied toward the determination of paracetamol (PCM) through proton oxidation by square wave adsorptive voltammetry (SWAdV). The anodic peak current for PCM increased by nearly 70.0% compared with an unmodified CP, and the detection limit was 0.020 μmol L-1. The relative standard deviations (RSDs) were 1.0% (n = 7). The accuracy of the new method was evaluated with tap water spiked with known quantities of PCM, while ascorbic acid, caffeine, and acetylsalicylic acid were used for interference studies. Finally, the usefulness of the microcomposite was shown to have acceptable results when applied to detect and quantify PCM in various forms of a pharmaceutical dose, such as solid tablets, fruit-flavored powders for colds and syrups for children.
NUEVOS COMPLEJOS “PINCER” DE ITRIO(III) ACTIVOS COMO CATALIZADORES EN POLIMERIZACIÓN DE ε-CAPROLACTONA MEDIANTE APERTURA DE ANILLO.
(2013) John Hurtado; René S. Rojas; Mauricio Valderrama
En una mezcla de los disolventes tolueno-tetrahidrofurano, se hizo reaccionar YCl3 con Li[N(SiMe3)2] para formar el producto YCl2[N(SiMe3)2](THF)3 (1). Este precursor se hizo reaccionar con los ligandos tridentados: 2,6-bis(3,5-dimetilpirazol-1-ilmetil)piridina y 2,6-bis(indazol-2-ilmetil)piridina obteniéndose los complejos pincer de fórmula general YCl2[N(SiMe3)2]{2,6-bis(azolilmetil)piridina-N,N,N}(2,3). Los complejos de itrio(III) fueron preparados a escala de RMN y caracterizados mediante técnicas espectroscópicas de RMN (1H, 13C, 29Si). A temperatura ambiente, los complejos mostraron una alta actividad catalítica para la polimerización de ε-caprolactona. Los polímeros obtenidos se caracterizaron por espectroscopía IR, RMN y para la determinación de los pesos moleculares se utilizó cromatografía de exclusión por tamaño (SEC)
Speciation of morin and rutin in black tea,Cymbopogon citratusand fruit infusions by adsorption voltammetry using screen-printed carbon electrodes coated with chitosan: effect of pH on speciation
(Royal Society of Chemistry, 2018) Édgar Nagles; Olimpo García‐Beltrán; John Hurtado
This paper presents the versatility of chitosan in the preparation of modified electrodes without the use of other substances.
Syntheses, Characterization and Photophysical Properties of Phthalimide-Pyrazole Compounds: Effect of the Substituent in the Pirazole Ring on the Crystal Structures
(RELX Group (Netherlands), 2024) David Ezenarro-Salcedo; Daniela Fonseca; Paulo C. Piquini; Bernardo A. Iglesias; Mario A. Macías; John Hurtado