RESUMEN
Zeolite imidazole frameworks (ZIFs), a class of the metal organic framework, have been extensively studied in environmental applications. However, their environmental fate and potential ecological impact on plants remain unknown. Here, we investigated the phytotoxicity, transformation, and bioaccumulation processes of two typical ZIFs (ZIF-8 and ZIF-67) in rice (Oryza sativa L.) under hydroponic conditions. ZIF-8 and ZIF-67 in the concentration of 50 mg/L decreased root and shoot dry weight maximally by 55.2% and 27.5%, 53.5% and 37.5%, respectively. The scanning electron microscopy (SEM) imaging combined with X-ray diffraction (XRD) patterns revealed that ZIFs on the root surface gradually collapsed and transformed into nanosheets with increasing cultivation time. The fluorescein isothiocyanate (FITC) labeled ZIFs were applied to trace the uptake and translocation of ZIFs in rice. The results demonstrated that the transformed ZIFs were mainly distributed in the intercellular spaces of rice root, while they cannot be transported to culms and leaves. Even so, the Co and Zn contents of rice roots and shoots in the ZIFs treated groups were increased by 1145% and 1259%, 145% and 259%, respectively, compared with the control groups. These findings suggested that the phytotoxicity of ZIFs are primarily attributed to the transformed ZIFs and to a less extent, the metal ions and their ligands, and they were internalized by rice root and increased the Co and Zn contents of shoots. This study reported the transformation of ZIFs and their biological effectiveness in rice, highlighting the potential environmental hazards and risks of ZIFs to crop plants.
Asunto(s)
Bioacumulación , Imidazoles , Oryza , Plantones , Contaminantes del Suelo , Zeolitas , Oryza/efectos de los fármacos , Oryza/metabolismo , Imidazoles/toxicidad , Plantones/efectos de los fármacos , Plantones/metabolismo , Contaminantes del Suelo/toxicidad , Estructuras MetalorgánicasRESUMEN
A novel copper-catalyzed cycloaddition of diaryl disulfides to heterobicyclic alkenes has been developed. The C-S and C-C bonds can be formed simultaneously on the CâC bond of the olefins via a single-step cycloaddition to afford a series of 2,3-dihydrobenzo[b]thiophene derivatives. This reaction exhibits excellent diastereoselectivity and relatively broad substrate scope. Various functional groups attached to the substrates are tolerated in this protocol to give the corresponding exo adducts in moderate yields.
RESUMEN
A sulfa-Michael/aldol/lactonization cascade reaction has been established to construct isotetronic acid-fused thiochromanes in a highly stereoselective fashion (≥11:1 dr, 35-98% ee). The tricyclic products were obtained in 35-99% isolated yields in the presence of a bifunctional squaramide. Three reactive sites of ß,γ-unsaturated α-ketoester, including the less-explored ester carbonyl group, were sequentially utilized to construct two fused heterocycles in a one-pot operation.
Asunto(s)
Ésteres , Catálisis , EstereoisomerismoRESUMEN
A cobalt(II)-catalyzed [4+2] annulation of picolinamides with alkynes via C-H bond activation has been developed. The operationally simple annulation reaction allows for the synthesis of acyl-substituted 1H-benzoquinoline bearing multiple aromatic rings (up to 96 % yield) without co-oxidant or other oxidation factors under mild conditions. Several control experiments were carried out. This practical [4+2] annulation provides an efficient route to access highly functionalized compounds.
RESUMEN
A novel copper-catalyzed hydrothioetherification of oxa(aza)bicyclic alkenes with potassium thioacetate and aryl or alkyl iodides to synthesize unsymmetrical thioethers has been developed. Notably, the reaction with complete diastereoselectivity went through a syn-selective addition process to give exo-adducts. In addition, this protocol exhibited high efficiency and good functional group tolerance to afford the target thioethers in moderate to good yields. Based on the results of mechanistic investigations, a plausible mechanism was proposed.
RESUMEN
A novel ICl/AgNO3 co-catalyzed radical oxidation of diaryl- and alkylarylalkynes into 1,2-diketones is reported. The reaction proceeded smoothly under mild conditions and generated 1,2-diketones in moderate to good yields with a good tolerance of functional groups. Furthermore, the obtained C4-(1,2-diketoaryl)isoxazoles could react smoothly with 1,2-diaminobenzene to form C4-(3-arylquinoxalin-2-yl)isoxazoles. At last, a new one-pot strategy for the synthesis of quinoxalines from 1,2-diphenylethynes and 1,2-diaminobenzene is also reported.
RESUMEN
A novel palladium-catalyzed ring-opening reaction of oxabicyclic alkenes with arylsulfonyl hydrazides was first developed. In this work, we provide an efficient one-pot reaction to afford the corresponding cis-2-aryl-1,2-dihydronaphthalen-1-ols and 2-aryl-naphthalenes in moderate to excellent yields (up to 95%) under an open-air condition. Various types of functional groups attached to the substrates were tolerated well in this method. Among them, the cis-1,2-configuration of product 3ag was confirmed by X-ray crystallographic analysis. In addition, a plausible mechanism for ring opening was also proposed.
RESUMEN
An efficient three-component cycloaddition of oxa(aza)bicyclic alkenes/norbornene in the presence of NaN3 and arylsulfonyl chlorides was developed, affording the corresponding aziridine products in good yields (up to 82%) with moderate to good endo/exo selectivities (up to >99:1 endo/exo). Further studies showed that the cycloaddition of oxa(aza)bicyclic alkenes in the presence of NaN3 and chloroalkanes could afford the exo-cycloadduct 1,2,3-triazolines in good to excellent yields (up to 95%). Compared with the existing methodologies, the current protocol demands very simple and mild reaction conditions and is a metal-free catalyzed reaction. In addition, a plausible mechanism for the cycloaddition reaction was also proposed.
RESUMEN
A new nickel-catalyzed syn-stereocontrolled ring-opening of oxa- and azabicyclic alkenes with dialkylzinc reagents was developed, which afforded the corresponding cis-2-alkyl-1,2-dihydronaphthalen-1-ols and 1,2-alkyl amide derivatives in moderate to excellent yields (up to 99% yield) under mild conditions. In this work, we successfully avoided obtaining hydride addition byproducts arising from ß-hydride elimination on an ethyl nickel species. Furthermore, a plausible mechanism for the ring-opening reaction was also proposed.
RESUMEN
A highly effective water-promoted iridium-catalyzed ring-opening reaction of oxa(aza)benzonorbornadienes with fluoroalkylamines was developed for the synthesis of fluorinated trans-1,2-amino alcohol or diamine derivatives. Tetrabutylammonium iodide (TBAI) was necessary as an additive for excellent yields in the presence of [Ir(COD)Cl]2 catalyst. Fluorinated trans-1,2-amino alcohol or diamine derivatives could be obtained in good to excellent yields (up to 98%) under mild conditions within a shorter period. Another interesting finding was that the addition of water could greatly enhance the ring-opening reaction. In addition, a plausible mechanism for the ring-opening reaction was proposed.
RESUMEN
Risk communication involves conveying potential risks to the audience. It's crucial for shaping behavior and influencing individual well-being. Previous research predominantly focused on verbal and written aspects of risk communication, with less emphasis on nonverbal cues like vocal tone. Addressing this gap, our study explores the impact of competent and warm vocal tones on risk communication across two risky decision-making paradigms, the Balloon Analogue Risk Task (BART) in Study 1 and the Gambling Task in Study 2. Results show that competent and warm vocal tones are more persuasive than neutral tones, and their effectiveness varies in different decision-making scenarios. Additionally, participants' perceived competence and warmth of vocal tones mediate this persuasiveness. This study enhances our theoretical understanding of risk communication by incorporating the impact of vocal tones. Also, it carries practical implications for marketers and practitioners, demonstrating the importance of using voice as a medium to persuade in real-world scenarios.
RESUMEN
Knowledge of the metabolism of functional enzymes is the key to accelerate the transformation and utilization of raw materials during high temperature Daqu (HTD) manufacturing. However, the metabolic contribution of raw materials-wheat is always neglected. In this research, the relationship between the metabolism of wheat and microorganisms was investigated using physicochemical and sequencing analysis method. Results showed that the process of Daqu generation was divided into three stages based on temperature. In the early stage, a positive correlation was found between Monascus, Rhizopus and glucoamylase metabolism (r > 0.8, p < 0.05). Meanwhile, the glucoamylase metabolism in wheat occupied 63.8 % of the total matrix at the day 4. In the middle to later stages, the wheat metabolism of proteases, α-amylases and lipases in gradually reached their peak. Additionally, Lactobacillus and α-amylases presented a positive correlation (r > 0.7, p < 0.05), and the α-amylases metabolism in wheat occupied 22.18 % of the total matrix during the same time period. More importantly, the changes of enzyme activity metabolic pathway in wheat and microorganism were reflected by respiratory entropy (RQ). Overall, these results guide the choice of substrate during Daqu production.
Asunto(s)
Bacterias , Microbiota , Fermentación , Bacterias/genética , Bacterias/metabolismo , Triticum/metabolismo , Glucano 1,4-alfa-Glucosidasa/metabolismo , Temperatura , alfa-Amilasas/metabolismo , Bebidas AlcohólicasRESUMEN
A novel copper-catalyzed complete diastereoselective 1,2-difunctionalization of oxabicyclic alkenes has been developed. Two C-S bonds were constructed simultaneously on the oxabenzonorbornadienes leading to ß-thiocyanato thioethers through the three-component (oxabicyclic alkenes, aryl iodides, and potassium thiocyanate), one-pot reaction. Various functional groups attached to the substrates were tolerated in this protocol to afford the corresponding ß-thiocyanato thioether products in moderate yields.
RESUMEN
A Pd-catalyzed Sonogashira cross-coupling reaction for the synthesis of C4-alkynylisoxazoles from 3,5-disubsitituted-4-iodoisoxazoles and terminal alkynes was described, which could afford the corresponding products with high yield (up to 98%). The results indicated that the steric effect from the group at the C3 position of the isoxazole had greater influence on the cross-coupling reaction than that from the group at the C5 position. In addition, the group at the C3 position of the isoxazole showed negligible electronic effects on the cross-coupling reaction. Furthermore, a gram-scale reaction of the Sonogashira coupling reaction was also investigated. Finally, a plausible mechanism for the Sonogashira coupling reaction was proposed.