Borchdamm6529

We develop a visible light-promoted divergent cycloaddition of α-diazo esters with hexahydro-1,3,5-triazines, leading to a series of aziridine and imidazolidine frameworks in average good yield, by simply changing the reaction media used. It is noteworthy that the reaction occurs under sole visible light irradiation without the need for exogenous photoredox catalysts. More significantly, a reasonable reaction mechanism was proposed on the basis of the control experiments and density functional theory calculation results.To ensure reliability and facilitate the strain engineering of zinc oxide (ZnO) nanowires (NWs), it is significant to understand their flexibility thoroughly. In this study, single-crystalline ZnO NWs with rich axial pyramidal I (π1) and prismatic stacking faults (SFs) are synthesized by a metal oxidation method. Bending properties of the as-synthesized ZnO NWs are investigated at the atomic scale using an in situ high-resolution transmission electron microscopy (HRTEM) technique. It is revealed that the SF-rich structures can foster multiple inelastic deformation mechanisms near room temperature, including active axial SFs' migration, deformation twinning and detwinning process in the NWs with growth π1 SFs, and prevalent nucleation and slip of perfect dislocations with a continuous increased bending strain, leading to tremendous bending strains up to 20% of the NWs. Our results record ultralarge bending deformations and provide insights into the deformation mechanisms of single-crystalline ZnO NWs with rich axial SFs.Reversible addition-fragmentation transfer (RAFT) dispersion polymerization of styrene was performed in an ethanol-water mixture using a Z-group carboxylated poly(N-acryloylmorpholine) (PNAM) macro-RAFT agent, and dialysis was performed against water to produce the PNAMx-PSy-COOH (PS = polystyrene) diblock copolymer latexes. This new formula is developed for the fabrication of pH-switchable copolymer latexes through an end-group response approach. The PNAM44-PS134-COOH latex is unstable at suitably low pH values (pH ≤ 4), and these aggregated spherical nanoparticles are redispersed successfully by adding base as determined by analysis of their dynamic light scattering (DLS) diameters and transmission electron microscopy (TEM) data. Negative zeta potential (-19.4 mV at 0.02% w/w) of the original latex indicated that carboxylic acid end-groups were anchored on the surface of the PS core via the polymerization-induced self-assembly (PISA) process and exposed to the solvent. Protonation of carboxylate groups reduces the degree of hydration of the PS core with a great impact on the free energy of the core/solvent interface, inducing the aggregation of PNAM44-PS134-COOH latex particles. A comparative experiment where the carboxylic acid end-group is designed on the PNAM stabilizer block proves that no pH-switchable behavior occurs in this case. Moreover, the vesicle-like nanoparticles composed of PNAM44-PS428-COOH copolymers have an apparently anionic character (zeta potential ≈ -33.5 mV at 0.02% w/w) and are still pH-switchable with a lower critical flocculation point (pH 2-3). More importantly, the latex composed of PNAM118-PS151-COOH diblock copolymers is insensitive to the solution pH.Molecular simulations with atomistic or coarse-grained force fields are a powerful approach for understanding and predicting the self-assembly phase behavior of complex molecules. Amphiphiles, block oligomers, and block polymers can form mesophases with different ordered morphologies describing the spatial distribution of the blocks, but entirely amorphous nature for local packing and chain conformation. Screening block oligomer chemistry and architecture through molecular simulations to find promising candidates for functional materials is aided by effective and straightforward morphology identification techniques. Capturing 3-dimensional periodic structures, such as ordered network morphologies, is hampered by the requirement that the number of molecules in the simulated system and the shape of the periodic simulation box need to be commensurate with those of the resulting network phase. Common strategies for structure identification include structure factors and order parameters, but these fail to identify emerging ordered patterns from nonequilibrium systems.This Letter describes a Pd-catalyzed Tsuji-Trost-type/Heck reaction with allyloxy-tethered aryl iodides and aziridines. The strategy provides efficient access to benzannulated medium-sized rings via intermolecular cyclization. The substrate aryl iodide has two oxidative addition sites, that is, the aromatic C-I bond and the allyl-oxygen bond. The chemoselective oxidative addition of allyl-oxygen bonds is favored, followed by the activation of aromatic C-I bonds. Aziridine plays a key role. Mechanistic studies shed light on the reaction pathway.To assist increasing annual acreage of Texas-grown (U.S.A.) strawberries, it is essential to select cultivars with excellent plant and fruit quality characteristics suitable to the diverse environments. This study assessed multiple traits of 10 strawberry cultivars grown under high tunnels. A significant difference (p ≤ 0.05) was observed for all traits, which possessed a wide variability of metabolites. Plant analysis (number of live plants, plant vigor, and harvest yield) indicated that the yield ranged from 226 to 431 g/plant, positively correlated to plant vigor. Fruit physicochemical characteristic analysis, including red color (absorbance at 500 nm) and taste-associated indicators [°Brix, titratable acidity (TA), and total soluble solids (TSS)/TA], showed that °Brix and TSS/TA ranged from 8.0 to 12.9 and from 9.1 to 15.3, respectively. More than 300 volatiles were identified using solid-phase microextraction-gas chromatography-mass spectrometry, and total volatiles varied 1.5 times with high variance of individual compounds between cultivars. Descriptive sensory analysis indicated that strawberry flavor was positively associated with sensory attributes of sweetness, jammy, fruity, buttery, fresh, and creamy while negatively related to bitterness, astringency, and sourness. Partial least squares regression indicated that strawberry flavor was highly correlated with sweet taste and volatile composition. No specific relationship between these traits and day-neutral or June-bearing varieties was identified. Ideal cultivars for Texas growing conditions with superior and balanced flavor qualities were Albion, Sweet Charlie, Camarosa, Camino Real, and Chandler.Photodynamic therapy (PDT) is used to treat various cancerous diseases. Recently, we have demonstrated that platinated pyridyl-substituted porphyrins are potent agents for PDT with very high phototoxicity (IC50 down to 17 nM) and excellent phototoxic indices of higher than 5800 (p.i. Selleckchem Gusacitinib = IC50(dark)/IC50(light)) [Rubbiani, R. et al., Chem. Commun. 2020, 56, 14373]. However, the absorption of porphyrins is not ideal for the treatment of larger tumors because they essentially do not absorb light between 650 and 850 nm. Herein, we report stable conjugates of a novel bacteriochlorin with cisplatin and transplatin. They exhibit extremely high phototoxicity (IC50 values down to 6 nM, irradiated with a 750 nm LED at a fluence of 5 J/cm2), very low dark toxicity, and thereby extremely high phototoxic indices up to 8300. Based on these exciting results, we believe that platinated bacteriochlorins are promising candidates for further investigation as novel PDT anticancer agents.Aqueous biphasic systems (ABSs) can form when mixing water with two compounds such as polymers, ionic liquids, or simple salts. While this phenomenon has been known for decades and found applications in various fields such as biology, recycling, or even more recently electrochemistry, the physics behind the formation of ABSs remains ill-understood. It was recently demonstrated that ABSs can be composed of two salts sharing the same cation (Li+) but different anions (sulfonamide and halide). Interestingly, their formation could not be explained by the position of the anions within the chaotropic/kosmotropic series and was rather proposed to originate from an anion size mismatch, albeit the size for these anions was never measured yet owing to the lack of a proper experimental methodology. Here, we combine experimental techniques and molecular simulations to assess the specific effects (size, shape, hydrophobic/hydrophilic character) of a series of anions and correlate them with the formation of ABSs. We demonstrate that while the anion size mismatch is a prerequisite for the formation of Li-salts based ABSs, their shape can also play an important role, providing general guidelines for forming new ABSs with potential future applications.Proteins are stable over a narrow temperature range, with hot and cold denaturation occurring outside of this window, both of which adversely affect protein function. While hot unfolding is entropically driven, cold denaturation, on the other hand, results from a more favorable free energy associated with the interaction of water with apolar groups at low temperature. Because of the key role of water in this latter process, capturing cold denaturation using implicit solvent models is challenging. We propose here a novel computational approach to develop an implicit solvent model that accounts for both hot and cold denaturation in simulations involving atomistically detailed protein representations. By mining a large number of protein structures solved by nuclear magnetic resonance, we derive transfer free energy contributions for the backbone and amino acids side chains representing the transfer of these moieties between water at two different temperatures. Using Trp-cage as a model system, we show that the implicit solvent model constructed using these temperature-dependent free energies of transfer recovers the parabolic temperature dependence of protein stability, capturing both hot and cold denaturation. The resulting cold-unfolded conformations show reduced secondary structure content but preserve most of their internal hydrogen-bonding network, in contrast to the extended configurations with no hydrogen-bonding populated during heat-induced denaturation.To promote the discovery and development of new fungicides, a series of novel pyrazol-5-yl-benzamide derivatives were designed, synthesized by hopping and inversion of amide groups of pyrazole-4-carboxamides, and evaluated for their antifungal activities. The bioassay data revealed that compound 5IIc exhibited an excellent in vitro activity against Sclerotinia sclerotiorum with an EC50 value of 0.20 mg/L, close to that of commercial fungicide Fluxapyroxad (EC50 = 0.12 mg/L) and Boscalid (EC50 = 0.11 mg/L). For Valsa mali, compound 5IIc (EC50 = 3.68 mg/L) showed a significantly higher activity than Fluxapyroxad (EC50 = 12.67 mg/L) and Boscalid (EC50 = 14.83 mg/L). In addition, in vivo experiments proved that compound 5IIc has an excellent protective fungicidal activity with an inhibitory rate of 97.1% against S. sclerotiorum at 50 mg/L, while the positive control Fluxapyroxad showed a 98.6% inhibitory effect. The molecular docking simulation revealed that compound 5IIc interact with TRP173, SER39, and ARG43 of succinate dehydrogenase (SDH) through a hydrogen bond and p-π interaction, which could explain the probable mechanism of the action between compound 5IIc and target protein.