N-Heterocyclic carbene (NHC) catalyzed radical-radical reactions have been proven to be powerful strategies for assembling ketyl-containing compounds via single electron transfer (SET) pathway under either thermal conditions or photoredox conditions. In this context, acylation of alkenes via radical relay under NHC-organocatalysis has also opened a new window for the difunctionalization of alkenes to construct valuable molecules in organic synthesis. In this review, the advances and progress of the acylation of alkenes via NHC-organocatalysis were summarized according to different ways of generation of the key NHC-bound ketyl-type radicals. Furthermore, reaction scopes, limitations and mechanisms were discussed based on reaction types and catalytic systems. Conclusions and perspectives were also put forward at the end.
Topological indices and QSPR analysis of some chemical structures applied for the treatment of heart patients
The results showed that certain topological indices had strong correlations with specific physicochemical properties. Quantitative structure property relationship modeling demonstrated that the best predictor of topological indices for physicochemical features was the H(G) index for (BP), (FP), and (E), the ReZG3$$ {}_3 $$ index for (P), (MR), and (MV), the I(G) index for (MR), the mM2$$ {}_2 $$ (G) index for (T) in linear regression models.
Abstract
In this study, various beta-blocker drugs used for heart disease were analyzed, and their degree-based topological indices derived from the M-polynomial were calculated. Linear and quadratic regression analysis was used to obtain quantitative structure-property relationship models between the topological indices and eight the physicochemical properties of the drugs to determine their effectiveness. The results show that the harmonic index was the best predictor for boiling point, flashpoint, and enthalpy of vaporization, while the redefined third Zagreb index was effective for polarizability, molar refractivity, and molar volume. The inverse sum indeg index was found to be effective for molar refractivity, and the second modified Zagreb index was surface tension in linear regression models. In addition, the redefined third Zagreb index was the best predictor for polarizability and molar refractivity, while the second modified Zagreb index was effective for molar volume. The SDD index was found to be effective for surface tension in quadratic regression models.
Ex vivo antiacetylcholinesterase studies on silver nanoparticles synthesized using green approach
The HH-AgNPs exhibited significant anti-AChE potential as compared to HH-plant extract and proved to be an herbal source for the treatment of AD.
For the green fabrication of silver nanoparticles (AgNPs), scientists are favoring herbal sources to avoid the toxic effects of synthetic sources. Thus, in this study, the AgNPs were generated using the herbal extract of the whole plant Hippeastrum hybridum L. (HH) and 1 mM AgNO3 aqueous solution. These HH-AgNPs were characterized via UV–Vis Spectroscopy, which showed a maximum absorbance of 1.61 at a 432 nm sharp peak; FT-R analysis, which confirmed the functional groups in HH extract and their AgNPs; XRD analysis, which gives 4-Bragg's reflections at 2θ and confirmed the HH-AgNPs crystal structure with 13.3 nm average size; SEM analysis, which confirmed the irregular-shaped morphology with 40 nm mean size; and EDX analysis, which confirmed the elemental composition and reported that Ag was present in 22.75%. After characterization, these AgNPs were tested as anti-Alzheimer agents against acetylcholinesterase (AChE) in ex vivo activity using rat brain homogenate as a source of AChE enzyme. AChE showed 48 ± 0.03 and 42 ± 0.05% activity at 150 μg concentration of HH plant and HH-AgNPs, respectively, with 145 ± 0.24 and 124.2 ± 0.14 μg IC 50 concentration. According to enzyme kinetics results, the plant extract inhibits AChE in competitive mode (K m increased from 166.2% to 1,379.2% and V max not affected), while HH-AgNPs showed the mixed mode of inhibition (K m increased from 0.029 to 0.048, and V max decreased from 9 to 5.4). K Iapp and V maxiapp were also calculated (K Iapp increased from 39 to 95.1 μg, and V maxiapp remained constant for the plant), while for HH-AgNPs, both K maxipp and V maxiapp increased from 122.32 to 325 μg and 8.15 to 9.8 μg, respectively. The K m , K i , and K I were also calculated and were found to be 0.017 mM (HH-plant) and 0.2 mM (HH-AgNPs); 98 μg (HH-plant); and 129 μg (HH-AgNPs), 53 μg (HH-plant), and 179 μg (HH-AgNPs), respectively. γK m (18 mM) was calculated for HH-AgNPs, while for HH-plant, it is not applicable. In conclusion, it could be said that HH-plant plays a significant role in the generation of small-size HH-AgNPs. These AgNPs exhibited significant anti-AChE potential as compared to HH-plant extract and proved to be an herbal source for the treatment of AD.
Enhancement of Propylene Metathesis Performance of MoO3/Al2O3 with Promotion of Phosphoric Acid
ChemCatChem, Accepted Article.
[ASAP] Mass-Activated Droplet Sorting for the Selection of Lysine-Producing Escherichia coli
Analytical Chemistry
DOI: 10.1021/acs.analchem.3c03080
Half‐sandwich Ru (II) complexes: Effect of ligands on aerobic oxidation of benzylamine
We use different donating systems for half-sandwich Ru (II) complexes to see the effect of ligands on aerobic oxidation of benzylamine.
In this study, we compared carbene and pyridine substituted ligands {3-Me-1-[2-(CH2CH2SPh)]-C7H4N2} (L1) and {2-[(2,6-iPr2-C6H3)N=CH]-6-(MeO)C5H3N}(L2) for synthesis of ionic C,S- and N,N-coordinated Ru (II) complexes [(κ2-L1)RuCl(η6-p-cymene)]+Cl− (1), [(κ2-L1)RuI(η6-p-cymene)]+I− (2), and [(κ2-L2)RuCl(η6-p-cymene)]+Cl− (3), respectively. Stannylene ligand [{2,6-(Me2NCH2)2C6H3}SnCl] (L3), as heavy carbene analog, was also used in this study to prepare neutral Sn-coordinated Ru (II) complex [(κ1-L3)RuCl2(η6-p-cymene)] (4). Finally, reaction of SnCl2 with 1, 3, and 4 was also studied to yield [(κ2-L1)RuCl(η6-p-cymene)]+[SnCl3]− (5), [(κ2-L2)RuCl(η6-p-cymene)]+[SnCl3]− (6), and [(κ1-L3)RuCl (SnCl3)(η6-p-cymene)] (7). The catalytic activity of 1–7 was tested on aerobic oxidation of benzylamine. The effect of different ligands L1–3 as well as the effect of the SnCl3 − moiety is discussed.
Cationic rhodium diphosphane complexes as efficient catalysts for the semi‐hydrogenation of dehydroisophytol
The selective reduction of terminal alkynes to alkenes was investigated using common cationic diphosphane rhodium complexes of the type [Rh(PP)(diolefin)]X (PP = diphosphane, X = anion). The effectiveness of the catalyst was demonstrated in the semi-hydrogenation of, dehydroisophytol (DIP), an industrial produced intermediate of vitamin E. The present study highlights the high activity and good selectivity of this simple catalytic system. However, deactivation increases at higher DIP concentrations. Several strategies to circumvent the deactivation are presented.
Manipulating Nanowires in Interconnecting Layer for Efficient Tandem Organic Photovoltaics
Abstracts
Owing to the function of manipulating light absorption distribution, tandem organic solar cells containing multiple sub-cells exhibit high power conversion efficiencies. However, there is substantial challenge in precisely controlling the inter-subcells carrier migration which determines the balance of charge transport across the entire device. The conductivity of “nanowires”-like conducting channel in interconnecting layer between sub-cells should be improved which calls for fine engineering on the morphology of polyelectrolyte in interconnecting layer. Here we develop a simple method to effectively manipulating the domains of conductive components in commercial available polyelectrolyte PEDOT:PSS. The using of poor solvent could effectively modify the configuration of polystyrene sulfonic acid and thus the space for conductive components. Based on our strategy, the insulated shells wrapping conductive domains are thinned and the efficiencies of tandem organic solar cells are improved. We believe our method might provide guidance for the manufacture of tandem organic solar cells.
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Recent advances in the synthesis and polymerization of new CO2‐based cyclic carbonates
Comprehensive Summary
Carbon dioxide can be converted into functional heterocycles known as cyclic carbonates, whose recent reactivity has been expanded towards the formation of tailor-made engineering polymers. This minireview gives an overview of the most topical developments in this area with a special focus on the synthetic methods employed to prepare these CO2 based synthons. In addition, their application potential in the area of polymer science using a variety of polymerization techniques is discussed that have in common the ring-opening of the carbonate monomers. Future perspectives are provided that provide impetus for the scientific communities aligning research to the use of sustainable processes for polymers from recyclable carbon sources such as CO2.
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Dual‐confined bead‐like CoSe2@NC@NCNFs bifunctional catalyst boosting rechargeable zinc‐air batteries
Comprehensive Summary
Rationally developing efficient and durable bifunctional catalysts toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critical for rechargeable zinc-air batteries (ZABs). Herein, a bead-like CoSe2@NC@NCNFs bifunctional catalyst was designed and fabricated by confining cubic CoSe2 nanoparticles to three-dimensional (3D) porous MOFs-derived nitrogen-doped carbon (NC) and one-dimensional (1D) N-doped carbon nanofibers (NCNFs) through a facile encapsulate strategy. The 1D/3D continuous network structure contributes to the improvement of specific surface area and electronic conductivity, while the strong synergistic effect between CoSe2 sites and Co-Nx-C sites can effectively enhance electron/mass transfer and reduce the diffusion resistance. The as-constructed CoSe2@NC@NCNFs catalyst exhibit high catalytic activity and stability toward ORR/OER with a high half-wave potential of 0.80 V (vs. RHE) in ORR and a low overpotential of 280 mV at 10 mA cm−2 in OER. More encouragingly, the rechargeable ZABs with CoSe2@NC@NCNFs cathode deliver high peak power densities (126.8 mW cm−2), large specific capacities (763.1 mA h g−1), and robust charge-discharge cycling stability over 240 cycles. This study provides a facile strategy for designing efficient bifunctional catalysts for rechargeable energy conversion applications.
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