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Molecules (Basel, Switzerland) Feb 2024A new chloroquine-derived photoaffinity probe has been prepared by a convergent synthesis from derivative of 4,7-dichloroquinoline and N1,N1-diethyl-N4-methylpentane....
A new chloroquine-derived photoaffinity probe has been prepared by a convergent synthesis from derivative of 4,7-dichloroquinoline and N1,N1-diethyl-N4-methylpentane. The features of this probe are a unique 3-azido photolabel, the pyridine ring of the quinoline, and the presence of a secondary amine at the 4-position of the quinoline. These features, particularly the 4-amino methylation, prevent triazole formation through combination of the 3-azide and the 4-amine. This undergoes facile cleavage with exposure to a medium-pressure mercury lamp with a 254 nm excitation wavelength. Trapping of the nitrene byproduct is accomplished with its reaction with N-phenylmaleimide as its cycloazidation product. The structure of a ring-opened DBU amine has been structurally characterized.
PubMed: 38474595
DOI: 10.3390/molecules29051084 -
Journal of Nanobiotechnology Mar 2024The primary factors that restrict agricultural productivity and jeopardize human and food safety are heavy metals (HMs), including arsenic, cadmium, lead, and aluminum,... (Review)
Review
The primary factors that restrict agricultural productivity and jeopardize human and food safety are heavy metals (HMs), including arsenic, cadmium, lead, and aluminum, which adversely impact crop yields and quality. Plants, in their adaptability, proactively engage in a multitude of intricate processes to counteract the impacts of HM toxicity. These processes orchestrate profound transformations at biomolecular levels, showing the plant's ability to adapt and thrive in adversity. In the past few decades, HM stress tolerance in crops has been successfully addressed through a combination of traditional breeding techniques, cutting-edge genetic engineering methods, and the strategic implementation of marker-dependent breeding approaches. Given the remarkable progress achieved in this domain, it has become imperative to adopt integrated methods that mitigate potential risks and impacts arising from environmental contamination on yields, which is crucial as we endeavor to forge ahead with the establishment of enduring agricultural systems. In this manner, nanotechnology has emerged as a viable field in agricultural sciences. The potential applications are extensive, encompassing the regulation of environmental stressors like toxic metals, improving the efficiency of nutrient consumption and alleviating climate change effects. Integrating nanotechnology and nanomaterials in agrochemicals has successfully mitigated the drawbacks associated with traditional agrochemicals, including challenges like organic solvent pollution, susceptibility to photolysis, and restricted bioavailability. Numerous studies clearly show the immense potential of nanomaterials and nanofertilizers in tackling the acute crisis of HM toxicity in crop production. This review seeks to delve into using NPs as agrochemicals to effectively mitigate HM toxicity and enhance crop resilience, thereby fostering an environmentally friendly and economically viable approach toward sustainable agricultural advancement in the foreseeable future.
Topics: Humans; Crop Production; Agriculture; Agrochemicals; Aluminum; Arsenic
PubMed: 38443975
DOI: 10.1186/s12951-024-02371-1 -
Scientific Reports Mar 2024Due to its widespread use in agriculture, atrazine has entered aquatic environments and thus poses potential risks to public health. Therefore, researchers have done...
Due to its widespread use in agriculture, atrazine has entered aquatic environments and thus poses potential risks to public health. Therefore, researchers have done many studies to remove it. Advanced reduction process (ARP) is an emerging technology for degrading organic contaminants from aqueous solutions. This study was aimed at evaluating the degradation of atrazine via sulfite/iodide/UV process. The best performance (96% of atrazine degradation) was observed in the neutral pH at 60 min of reaction time, with atrazine concentration of 10 mg/L and concentration of sulfite and iodide of 1 mM. The kinetic study revealed that the removal of atrazine was matched with the pseudo-first-order model. Results have shown that reduction induced by and direct photolysis dominated the degradation of atrazine. The presence of anions ( , and ) did not have a significant effect on the degradation efficiency. In optimal conditions, COD and TOC removal efficiency were obtained at 32% and 4%, respectively. Atrazine degradation intermediates were generated by de-chlorination, hydroxylation, de-alkylation, and oxidation reactions. Overall, this research illustrated that Sulfite/iodide/UV process could be a promising approach for atrazine removal and similar contaminants from aqueous solutions.
PubMed: 38433251
DOI: 10.1038/s41598-024-55585-6 -
The Journal of Physical Chemistry. A Mar 2024Though there is a growing body of literature on the kinetics of CIs with simple carbonyls, CI reactions with functionalized carbonyls such as hydroxyketones remain...
Though there is a growing body of literature on the kinetics of CIs with simple carbonyls, CI reactions with functionalized carbonyls such as hydroxyketones remain unexplored. In this work, the temperature-dependent kinetics of the reactions of CHOO with two hydroxyketones, hydroxyacetone (AcOH) and 4-hydroxy-2-butanone (4H2B), have been studied using a laser flash photolysis transient absorption spectroscopy technique and complementary quantum chemistry calculations. Bimolecular rate constants were determined from CHOO loss rates observed under pseudo-first-order conditions across the temperature range 275-335 K. Arrhenius plots were linear and yielded -dependent bimolecular rate constants: () = (4.3 ± 1.7) × 10 exp[(1630 ± 120)/] and () = (3.5 ± 2.6) × 10 exp[(1700 ± 200)/]. Both reactions show negative temperature dependences and overall very similar rate constants. Stationary points on the reaction energy surfaces were characterized using the composite CBS-QB3 method. Transition states were identified for both 1,3-dipolar cycloaddition reactions across the carbonyl and 1,2-insertion/addition at the hydroxyl group. The free-energy barriers for the latter reaction pathways are higher by ∼4-5 kcal mol, and their contributions are presumed to be negligible for both AcOH and 4H2B. The cycloaddition reactions are highly exothermic and form cyclic secondary ozonides that are the typical primary products of Criegee intermediate reactions with carbonyl compounds. The reactivity of the hydroxyketones toward CHOO appears to be similar to that of acetaldehyde, which can be rationalized by consideration of the energies of the frontier molecular orbitals involved in the cycloaddition. The CHOO + hydroxyketone reactions are likely too slow to be of significance in the atmosphere, except at very low temperatures.
PubMed: 38428028
DOI: 10.1021/acs.jpca.4c00156 -
Frontiers in Microbiology 2024Pharmaceuticals, recognized for their life-saving potential, have emerged as a concerning class of micropollutants in the environment. Even at minute concentrations,... (Review)
Review
Pharmaceuticals, recognized for their life-saving potential, have emerged as a concerning class of micropollutants in the environment. Even at minute concentrations, chronic exposure poses a significant threat to ecosystems. Various pharmaceutically active micropollutants (PhAMP), including antibiotics, analgesics, and hormones, have been detected in underground waters, surface waters, seawater, sewage treatment plants, soils, and activated sludges due to the absence of standardized regulations on pharmaceutical discharge. Prolonged exposureof hospital waste and sewage treatment facilities is linked to the presence of antibiotic-resistant bacteria. Conventional water treatment methods prove ineffective, prompting the use of alternative techniques like photolysis, reverse osmosis, UV-degradation, bio-degradation, and nano-filtration. However, commercial implementation faces challenges such as incomplete removal, toxic sludge generation, high costs, and the need for skilled personnel. Research gaps include the need to comprehensively identify and understand various types of pharmaceutically active micropollutants, investigate their long-term ecological impact, develop more sensitive monitoring techniques, and explore integrated treatment approaches. Additionally, there is a gap in understanding the socio-economic implications of pharmaceutical pollution and the efficacy of public awareness campaigns. Future research should delve into alternative strategies like phagotherapy, vaccines, and natural substance substitutes to address the escalating threat of pharmaceutical pollution.
PubMed: 38419628
DOI: 10.3389/fmicb.2024.1339469 -
Scientific Reports Feb 2024A sulfur nanoparticles-incorporated iron-doped titanium oxide (Fe/TiO) with different ratio was successfully synthesized by photolysis method and utilized as effective...
A sulfur nanoparticles-incorporated iron-doped titanium oxide (Fe/TiO) with different ratio was successfully synthesized by photolysis method and utilized as effective photoanode in dye sensitized solar cell (DSSC) application with N719 dye. The photolysis method was contained the irradiation of the Fe, S and Ti mixture solution with 15 W source irradiation, and then calcined the formed precipitate. The DSSCs fabricated with Fe/S-TiO photoanode appeared an improved solar-to-electrical energy conversion efficiency of 6.46, which more than pure TiO (3.43) below full sunlight illumination (1.5 G). The impact of Fe content on the total efficiency was also inspected and the Fe content with 6% S-TiO was found 5 wt%. Due to the improved the efficiency of solar cell conversion of Fe/S-TiO nanocomposite, it should be deemed as a potential photoanode for DSSCs with high performance.
PubMed: 38418464
DOI: 10.1038/s41598-024-54895-z -
Accounts of Chemical Research Mar 2024ConspectusAn understanding of the mechanistic processes that underpin reactions catalyzed by 3d transition metals is vital for their development as potential...
ConspectusAn understanding of the mechanistic processes that underpin reactions catalyzed by 3d transition metals is vital for their development as potential replacements for scarce platinum group metals. However, this is a significant challenge because of the tendency of 3d metals to undergo mechanistically diverse pathways when compared with their heavier congeners, often as a consequence of one-electron transfer reactions and/or intrinsically weaker metal-ligand bonds. We have developed and implemented a new methodology to illuminate the pathways that underpin C-H bond functionalization pathways in reactions catalyzed by Mn-carbonyl compounds. By integrating measurements performed on catalytic reactions with in situ reaction monitoring and state-of-the-art ultrafast spectroscopic methods, unique insight into the mode of action and fate of the catalyst have been obtained.Using a combination of time-resolved spectroscopy and in situ low-temperature NMR studies, we have shown that photolysis of manganese-carbonyl precatalysts results in rapid (<5 ps) CO dissociation─the same process that occurs under thermal catalytic conditions. This enabled the detection of the key states relevant to catalysis, including solvent and alkyne complexes and their resulting transformation into manganacycles, which results from a migratory insertion reaction into the Mn-C bond. By systematic variation of the substrates (many of which are real-world structurally diverse substrates and not simple benchmark systems) and quantification of the resulting rate constants for the insertion step, a universal model for this migratory insertion process has been developed. The time-resolved spectroscopic method gave insight into fundamental mechanistic pathways underpinning other aspects of modern synthetic chemistry. The most notable was the first direct experimental observation of the concerted metalation deprotonation (CMD) mechanism through which carboxylate groups are able to mediate C-H bond activation at a metal center. This step underpins a host of important synthetic applications. This study demonstrated how the time-resolved multiple probe spectroscopy (TRPS) method enables the observation of mechanistic process occurring on time scales from several picoseconds through to μs in a single experiment, thereby allowing the sequential observation of solvation, ligand substitution, migratory insertion, and ultimate protonation of a Mn-C bond.These studies have been complemented by an investigation of the "in reaction flask" catalyst behavior, which has provided additional insight into new pathways for precatalyst activation, including evidence that alkyne C-H bond activation may occur before heterocycle activation. Crucial insight into the fate of the catalyst species showed that excess water played a key role in deactivation to give higher-order hydroxyl-bridged manganese carbonyl clusters, which were independently found to be inactive. Traditional in situ IR and NMR spectroscopic analysis on the second time scale bridges the gap to the analysis of real catalytic reaction systems. As a whole, this work has provided unprecedented insight into the processes underpinning manganese-catalyzed reactions spanning 16 orders of magnitude in time.
PubMed: 38412502
DOI: 10.1021/acs.accounts.3c00774 -
ACS Omega Feb 2024The 266 nm photolysis of various positional isomers of dimethylpyridines and trimethylpyridine was investigated by measuring the translational energy distribution of the...
The 266 nm photolysis of various positional isomers of dimethylpyridines and trimethylpyridine was investigated by measuring the translational energy distribution of the methyl radical following {sp}C-C{sp} bond dissociation. The observed translational energy distribution is attributed to the dissociative photoionization in the cationic ground state following [1 + 1 + 1] three-photon absorption. The translational energy distribution profiles of the methyl radical were broad with the maximum translation energy in excess of 2 eV, which originates due to the dissociation of {sp}C-C{sp} bond ortho to the N atom in the ring. The dynamics of {sp}C-C{sp} bond dissociation in the cationic ground state of methylpyridines is marginally dependent on the number and position of the methyl groups; similar to xylenes, however, it is site-selective with the preferential cleavage of C-C bond in the ortho position to the pyridinic nitrogen atom, which is attributed to the relative stability of the resulting radical cation.
PubMed: 38405504
DOI: 10.1021/acsomega.3c08705 -
Heliyon Feb 2024The present study serves experimental and theoretical analyses in developing a hybrid advanced structure as a photolysis, which is based on electrospun Graphene...
The present study serves experimental and theoretical analyses in developing a hybrid advanced structure as a photolysis, which is based on electrospun Graphene Oxide-titanium dioxide (GO-TiO) nanofibers as an electron transfer material (ETMs) functionalized for perovskite solar cell (PVSCs) with GO. The prepared ETMs were utilized for the synthesis of mixed-cation (FAPbI3)0.8(MAPbBr3)0.2. The effect of GO on TiO and their chemical structure, electronic and morphological characteristic were investigated and discussed. The elaborated device, namely ITO/Bl-TiO/3 wt% GO-TiO2/(FAPbI3)0.8(MAPbBr3)0.2/spiro-MeTAD/Pt, displayed 20.14% disposition and conversion solar energy with fill factor (FF) of 1.176%, short circuit current density (Jsc) of 20.56 mA/cm and open circuit voltage (VOC) 0.912 V. The obtained efficiency is higher than titanium oxide (18.42%) and other prepared GO-TiO composite nanofibers based ETMs. The developed materials and device would facilitate elaboration of advanced functional materials and devices for energy storage applications.
PubMed: 38404854
DOI: 10.1016/j.heliyon.2024.e26633 -
Molecules (Basel, Switzerland) Feb 2024Photochemical reactions of salicylhydroxamic acid were induced using tunable UV laser radiation followed by FTIR spectroscopy. Four pairs of co-products were...
Photochemical reactions of salicylhydroxamic acid were induced using tunable UV laser radiation followed by FTIR spectroscopy. Four pairs of co-products were experimentally found to appear in the photolysis: CH(OH)NCO⋯HO (1), CH(OH)C(O)N⋯HO (2), CH(OH)⋯HNCO (3), and CH(OH)NHOH⋯CO (4). The comparison of the theoretical spectra with the experimental ones allowed us to determine the structures of the complexes formed in the matrices. The mechanisms of the reaction channels leading to the formation of the photoproducts were proposed. It was concluded that the first step in the formation of the complexes (1), (2), and (3) was the scission of the N-O bond, whereas the creation of complex (4) was due to cleavage of the C-N bond.
PubMed: 38398614
DOI: 10.3390/molecules29040862