Journal of the Chilean Chemical Society

POLYLACTIC ACID (PLA) SCAFFOLD FOR CONTROLLED RELEASE OF ESSENTIAL OIL OF CANELO DRIMYS WINTERI: CONTROL OF PHYTOPATHOGENS IN FRUITS

Christian Nuñez Duran — 2025-06-28

We have designed and prepared polylactic acid (PLA)-based porous support for the controlled release of essential oils from Drimys winteri, common name Canelo (CEO). The chemical composition of the essential oil was characterized by HS/GC-MS. The interaction with the PLA-based porous support was determined by FTIR-ATR spectrophotometry. Our results showed that the manufactured PLA support allows the controlled release of essential oils over time, at 21 °C. The PLA/essential oil support showed a non-contact antifungal activity against B. cinerea. In addition, pure compounds (standards) detected in the gas phase of CEO essential oil were independently studied to identify which of these molecules is responsible for the growth control action of the fungus. In conclusion, the PLA/CEO porous support is an alternative to protect against infections such as B. cinerea, offering a potential use of this strategy to preserve fresh functional foods in the post-harvest stage, as an atmosphere modifier.

AN OPTIMIZED KINETIC SPECTROPHOTOMETRIC METHOD FOR THE RAPID AND ACCURATE DETERMINATION OF CEFOPERAZONE IN URINE AND TAP WATER SAMPLES

CESAR SOTO — 2025-06-28

This study presents a new approach for quantifying the antibiotic cefoperazone (CPZ) in spiked urine and tap water samples using an indirect kinetic
spectrophotometry method. The method involves the oxidation of CPZ by permanganate (MnO₄^-) in an alkaline media. The progress of the reaction
is monitored by tracking the increase in manganate (MnO₄^2-) at 610 nm. The optimization of chemical-dependent variables was achieved through the utilization of multivariate statistical methods. The optimized values were 5 minutes of reaction time, KMnO₄ of 1.11 · 10 ^-3mol L⁻¹, and NaOH of
0.27 mol L⁻¹. Under these conditions, calibration curves were constructed. The detection limits obtained in urine and tap water spiked samples were
3.75 · 10⁻⁷ mol L⁻¹ and 3.74 · 10⁻⁷ mol L⁻¹, respectively. The results showed that intraday and interday recoveries ranged from 98.25 to 102.7%, indicating acceptable differences between observed and expected values according to the confidence percentage established as a criterion of acceptability; thus, demonstrating repeatability in results as well as satisfactory accuracy for this kinetic analytical method.

HYBRID MATERIAL BASED IN METAL-ORGANIC FRAMEWORK SUPPORTED ON ACTIVATED CARBON AS NOVEL MATERIALS FOR CO2 ADSORPTION FOR ENVIRONMENTAL APPLICATIONS

Erwin Sepúlveda — 2025-06-28

A composite of Ni-MOF-5 (Ni_xZn_4-xO(HCOO)₃(BCD)₃ (0<x<4)) and activated carbon were synthesized through a microwave synthesis method with reflux. Various characterization techniques were performed, including XRD, TGA, SEM, EDS, FT-IR, and BET isotherm. The surface study of the material shows the presence of crystals with a cubic structure of Ni-MOF-5 with sizes smaller than 10 µm. A superficial area of 718 m²/g and thermostability with a mass loss of 4.72% at 459°C of the metal-organic framework were observed. The results for different CO₂ concentrations at 1 bar and 25 °C show that the adsorption capacity had a linear relationship between % CO₂ and the amount of CO₂ adsorbed by the hybrid material. The results also showed that by increasing the working temperature in the CO₂ adsorption process and keeping the percentage of CO₂ constant, the amount of adsorbed CO₂ decreases linearly. The adsorption kinetics of CO₂ on the prepared hybrid material are consistent with the intraparticle diffusion model, where diffusion is the rate-limiting step. The adsorption of CO₂ is energetically and kinetically favorable due to the micro-mesoporosity of the material that allows the entry of CO₂molecules into the pores.

EXPLORING ARYL-SUBSTITUTED 1,2,3-TRIAZOLES: SYNTHESIS, CHARACTERIZATION, AND THEORETICAL INVESTIGATIONS

Cesar Morales — 2025-06-28

This study synthesized newly designed 1,2,3-triazoles substituted with aryl groups via Sharpless' copper(I)-catalyzed azide-alkyne cycloaddition. The resulting compounds were extensively characterized using NMR and UV-Vis spectroscopy. Furthermore, theoretical DFT and time-dependent DFT calculations were performed to analyze the structural and electronic properties of these molecules. Computational analysis revealed insights into the electron distribution within these molecules, with the electron-withdrawing or electron-donating nature of the substituents affecting the HOMO-LUMO gap. These findings provide valuable information for tailoring the electronic properties of triazole-containing compounds, making them suitable for various chemical applications and potential coordination with metalloporphyrins.

SYNTHESIS, ELECTRONIC AND PHOTOPHYSICAL PROPERTIES OF 3,8-DIAROMATIC-1,10-PHENANTHROLINE MOLECULES

José Muñoz — 2025-06-28

The molecules 3,8-diphenyl-1,10-phenanthroline (L₁), 3,8-di(naphthalen-1-yl)-1,10-phenanthroline (L₂), 3,8-di(naphthalen-2-yl)-1,10-phenanthroline (L₃), 3,8-di(anthracen-9-yl)-1,10-phenanthroline (L₄), and 3,8-di(pyren-1-yl)-1,10-phenanthroline (L₅) were prepared in good yield from the reaction of 3,8-dibromo-1,10-phenanthroline with the corresponding boronic acid, catalysed by [Pd(PPh₃)₄]. Computational DFT modelling suggests that the aromatic substituent arms are not coplanar with the central phenanthroline (phen) core, and that the HOMO-LUMO gap diminishes as the number of fused carbon rings in the arms increases. Cyclic voltammograms for the ligands show between one and two oxidation and one to three reduction waves, which are believed to be centred on the arms and the central phen fragments, respectively, suggesting some small electronic mixing. The absorption and emission properties depend on the electronic interaction between the polyaromatic substituents and the phenanthroline core. Different emissive ππ* excited states for the molecules bearing anthryl and pyrenyl substituents suggest they have more charge transfer character, and a consequent sensitivity to the increase of solvent polarity. The photosensitizing capacity of singlet oxygen generation upon excitation of L₁-L₅ in solution is consistent with a significant evolution of the former singlet excited state towards a triplet excited state.

ACTIVATED CARBON, BIOCHAR, AND LIGNOCELLULOSIC DERIVATIVE MATERIALS FOR REMOVING ANTIBIOTICS FROM WATER: AN OVERVIEW

Camila Negrete-Vergara — 2025-06-28

Antibiotics have improved the quality of life of human society due to their applications in medicine and food production. Nevertheless, antibiotics are also considered emerging pollutants because they have been found in the environment, water sources, and tap water. Their chemical stability and the excessive usage of these substances are the main causes of their presence in the environment. Antibiotics can be removed from water using adsorbent materials, in which activated charcoal has been extensively used for removing organic pollutants. Concerns about the environmental impact of producing activated charcoal are placing the interest in new eco-friendly materials for organic pollutant removal from water such as biochar and lignocellulosic materials. Those materials have desirable properties that allow them to remediate water in the presence of antibiotics.

In this study, the use of activated carbon, biochar, and lignocellulosic materials for removing antibiotics from water is reviewed. Here we discuss the advantages and limitations of each material for the aforementioned purpose, comparing their efficiency in the removal of common antibiotics used in healthcare and agroindustry, and considering new approaches and alternatives to the technologies used for antibiotic removal from water.

THE EFFECT OF BAND ENGINEERING OF SEMICONDUCTORS AND OTHER FACTORS ON PHOTOCATALYIC DEGRADATION OF ORGANIC POLUTANTS, TOWARDS A SCALE OF PHOTOCATALYTIC EFFECTIVENESS: A MULTIFACTORIAL EQUATION FOR THE PHOTOCATALYIC EFFICENCE. A REVIEW

Maria Luisa Valenzuela Valdes — 2025-06-28

The direct conversion of solar energy using a photocatalyst in a degradation of a pollutant reaction is a source of a sustainable and clean environment remediation.

In general, photocatalyst are semiconductors that possess valence and conduction bands. These energy bands permit the absorption of photon energy to excite electrons in the outer orbitals of the photocatalyst. Photoexcited electron and hole pairs can subsequently induce a reaction that degrade organic pollutant molecules. Photocatalyst degradation of pollutants is affected by the band level and crystallinity of the photocatalyst among others, therefore, band engineering using chemical modifications as particle size, morphology and physical as band gap could create photocatalyst suitable for the large-scale photodegradation of organic pollutant. In this Review, different factors of the photocatalyst obtained by solid-state, such as size, morphology, band gap and others are analyzed in the photocatalyst efficiency of the degradation of organic contaminant. This review involves binary metal oxide photocatalyst of the MxOy type, prepared from a solid-state route. The photocatalytic degradation of blue methylene using our the solid-state TiO₂, Fe₂O₃, NiO, ReO₃, IrO₂, Rh₂O₃, Rh/RhO₂, and the actinide ThO₂ prepared nanostructured metal oxides by a solid state method is described and discussed. Also, other studies of photocatalysis also prepared in solid state for the degradation of methylene blue and reported in the literature are shown and analyzed. With regard the photocatalytic efficiency, factors such as the particle size and morphology, the crystalline phase and the pyrolysis temperature used in the solid-state preparation method are very important. A multifactorial equation that summarizes the main factors that govern the photocatalytic efficiency of a photocatalyst is proposed. A parameterization of these factors is discussed through an equation of the photocatalytic efficiency as a function of these parameters. The importance of each of these parameters/factors in the photocatalytic efficiency against methylene blue degradation is discussed.