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    Supramolecular Control on the Reactivity of New Quinolin-2(1h)-one derivatives Induced by Micellar systems
    (2025) Quintero Faúndez, Guillermo Esteban; Aliaga Miranda, Margarita Elly; Espinosa Bustos, Christian Marcelo; Pontificia Universidad Católica de Chile. Facultad de Química y de Farmacia
    Six new quinolin-2(1H)-one derivatives (E)-6-methoxy-1-methyl-3-(2-(3-methyl-4-nitroisoxazol-5-yl)vinyl)quinolin-2(1H)-one (MQI), 7-(diethylamino)quinolin-2(1H)-one-3-carbaldehyde (DQD1), 7-(diethylamino)-1-methylquinolin-2(1H)-one-3-carbaldehyde (DQD2), (E)-7-(diethylamino)-3-(3-(3-(4-nitrophenyl)-3-oxoprop-1-en-1-yl)-1-methylquinolin-2(1H)-one (DQD3), (E)-7-(diethylamino)-3-(3-(4-fluorophenyl)-3-oxoprop 1-en-1-yl)-1-methylquinolin-2(1H)-one (DQCh) and (E) 7(Diethylamino)-1-methyl-3-(2-(3-methyl-4-nitroisoxazol-5-yl)vinyl)quinolin-2(1H)-one (DQI) were synthesized and evaluated as colorimetric and fluorescent probes for bisulfite (HSO3) in aqueous micellar solutions. The compound MQI, designed as a Michael acceptor, showed low water solubility but significantly enhanced reactivity toward HSO3 in aqueous cationic micellar solution of cetyltrimethylammonium bromide (CTABr), with rate constants up to 200-fold higher than in zwitterionic systems, such as 3-(N,N-dimethyltetradecylammonium) propanesulfonate (SB3-14). On the other hand, DQD1-3, DQCh, and DQI were developed to improve the fluorescence response of quinoline-2(1H)-one ring. Notably, DQI displayed rare inverse solvatofluorochromism, dependent on solvent polarity, making it only the second reported case of this behavior in organic dyes to date. While DQD3 did not exhibit the appropriate photophysical or reactivity criteria due to the presence of both E/Z isomers, the other derivatives demonstrated the presence of only the E isomer (valid for DQCh and DQI), promising behavior in micellar systems, with binding constants (Ks) in the range of 103−106 M−1. Photophysical studies in water and micellar environments revealed that DQCh had the highest fluorescence quantum yield (𝜙𝑓) and excellent selectivity for HSO3 over other anions and biothiols. Complementarily, DQCh was testedin real sample analysis (white wine samples) with good results, also DFT calculations confirmed the adequate reactivity of the double-bound C-C ,-unsatured. On the other hand, DQI showed a low fluorescence and exhibited fast and selective “turn-off” responses to HSO3 and hypochlorite (ClO). Its reaction was supported by NMR analysis of Michael adduct formation. Overall, this study introduces new quinolin-2(1H)-one-based platforms for selective HSO3 −and/or ClO− sensing, highlighting the importance of aqueous micellar medium in tuning chemical reactivity and fluorescence properties. The findings contribute to developing functional probes for environmental and food analysis in an aqueous micellar solution, avoiding toxic organic solvents.
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    The ALeRCE LC Classifier transient sample from 5 yrs of ZTF alerts
    (2025) Correa Orellana, Javier Ignacio; Bauer, Franz Erik; Catelan, Márcio; Pontificia Universidad Católica de Chile. Facultad de Física. Instituto de Astrofísica
    Extragalactic transients such as supernovae are some of the most powerful phenomena in the universe, and have enabled multiple studies in thefields such as star formation and stellar evolution beyond the Milky Way,nucleosynthesis and cosmology. Specifics on their progenitors are still anopen question, and host galaxies can provide important context, since theirstellar populations are linked to potential progenitors.Theadvent of unbiased wide-field surveys has provided homogeneous samples of transients, with machine learning codes helping to leverage as muchinformation as possible. In this pursuit, we assembled a sample of transients from the Automatic Learning for the Rapid Classification of EventsLight Curve Classifier discovered by the Zwicky Transient Facility between2018 and 2023, including 22627 transients out to z∼0.5, with 7269 having spectroscopic classifications in the Transient Name Server. Transientswere associated to their host galaxies, for which we extracted photometry,collected redshifts, and fit them with spectral energy distributions to derive physical properties such as stellar mass and star formation rate. Thesefeatures, along some regarding their light curves shapes and peaks, werecompiled into a catalog for publication, one of the largest of its kind.The catalog was used to assess transient properties and transient-hostrelations from the literature. We found consistency with previous worksregarding transient luminosities and physical properties of their host galaxies, with higher statistical significance given the larger sample size. Theseresults set important precedents for the future (e.g., Rubin Observatory).