Transformation of the pheromone 3‐methyl‐2‐cyclohexen‐1‐ol in the presence of [RuClCp (PTA)2] and [RuCp (OH2)(PTA)2]CF3SO3

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Transformation of the pheromone 3-methyl-2-cyclohexen-1-ol in the presence of [RuClCp (PTA)2] and [RuCp (OH2)(PTA)2]CF3SO3

The Douglas-fir beetle's pheromones 1-methyl-2-cyclohexen-1-ol, 3-methyl-2-cyclohexenone, and 3-methylcyclohexanone were synthesized from 3-methyl-2-cyclohexen-1-ol by simple one-pot reactions, in mild conditions, using solvents such as water. The reaction mechanisms were also investigated.


The catalytic conversion of the substituted cyclic allylic alcohol 3-methyl-2-cyclohexen-1-ol was studied in the presence of the metal complexes [RuClCp (PTA)2] (1) and [RuCp (OH2)(PTA)2]CF3SO3 (2) (PTA = 1,3,5-triaza-7-phosphaadamantane) in different media such as water, methanol, and biphasic water/cyclohexane. Slight changes of the reaction conditions led to the isomerization to 3-methylcyclohexanone, oxidation to 3-methyl-2-cyclohexenone, or 1,3-transposition to 1-methyl-2-cyclohexen-1-ol. The 1,3-transposition and oxidation reactions took place in water, and the selective formation of the isomerization product was achieved in freshly dried methanol, or biphasic water/cyclohexane mixture, achieving the highest TON values known to date. Furthermore, the reactivity of 3-methyl-2-cyclohexen-1-ol in water was also investigated in the absence of a catalyst, revealing the formation of the 1,3-transpostion product 1-methyl-2-cyclohexen-1-ol and the etherification product 1-methyl-3-(3-methyl-2-cyclohexen-1-yl)oxycyclohexene. Finally, key mechanistic aspects of the different reaction pathways were enlightened by NMR spectroscopy.

Synthesis and application of CoFe₂O₄@THAM@PHG‐SO₃H nanoparticles as a new and highly recyclable nanocatalyst in the one‐pot multicomponent synthesis of 3,4‐dihydropyranochromenes and chromeno[3,4‐b]quinoline‐6‐ones

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Synthesis and application of CoFe₂O₄@THAM@PHG-SO₃H nanoparticles as a new and highly recyclable nanocatalyst in the one-pot multicomponent synthesis of 3,4-dihydropyranochromenes and chromeno[3,4-b]quinoline-6-ones

The authors of this study have developed a new environmentally-friendly magnetic nanocatalyst by treating CoFe₂O₄ magnetic nanoparticles with chlorosulfonic acid, tris(hydroxymethyl)aminomethane (THAM), 1,2-dichloroethane, and phloroglucinol (PHG). They confirmed the synthesis of the catalyst using various techniques such as FT-IR, SEM, MAP, EDS, XRD, TGA, DTA, and VSM. The researchers then evaluated the catalytic efficiency of the nanocatalyst in two reactions: the synthesis of 3,4-dihydropyranochromenes and the synthesis of chromeno[3,4-b]quinoline-6-ones.


In this study, we have developed a new environmentally-friendly magnetic nanocatalyst by treating CoFe₂O₄ magnetic nanoparticles with chlorosulfonic acid, tris(hydroxymethyl)aminomethane (THAM), 1,2-dichloroethane, and phloroglucinol (PHG). They confirmed the synthesis of the catalyst using various techniques such as FT-IR, SEM, MAP, EDS, XRD, TGA, DTA, and VSM. The researchers then evaluated the catalytic efficiency of the nanocatalyst in two reactions: the synthesis of 3,4-dihydropyranochromenes from the reaction among aromatic aldehydes, 4-hydroxycoumarin, and malononitrile, and the synthesis of chromeno[3,4-b]quinoline-6-ones from the reaction among aniline, 4-hydroxycoumarin, and aromatic aldehydes.

Heliotropium eichwaldi‐functionalized gold nanoparticles synthesis, characterization, and biological activities

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Heliotropium eichwaldi-functionalized gold nanoparticles synthesis, characterization, and biological activities

In comparison with HE extract and hydrogen tetrachloroaurate (III) trihydrate (HAuCl4.3H2O) solution, the AuNPs have shown outstanding inhibitory activity against free radicals, -amylase, and AChE.


Nanoparticles (NPs) are the essential building block of nanotechnology; they have a wide range of biomedical applications. In comparison with chemical methods, green synthesis is significant because of their non-toxicity, eco-friendliness, and simplicity; thus, the plant extracts are useful in the biogenic synthesis of NPs. In this study, Heliotropium eichwaldi-induced gold NPs (HE-AuNPs) were produced. These HE-AuNPs were afterward examined using UV–vis spectroscopy, FTIR, SEM, XRD, and EDX analysis. The XRD analysis authorized the crystalline structure of AuNPs with an average size of 11.11 nm for four peaks (38.31°, 44.39°, 64.76°, and 77.65°), the SEM analysis displayed the elongated sphere-shaped morphologies of HE-AuNPs with 20 nm size, and the EDX analysis revealed that Au (44.33%) was the main element of AuNP. The FTIR analysis confirmed the presence of various coating and reducing organic molecules. In comparison with HE extract and hydrogen tetrachloroaurate (III) trihydrate (HAuCl4.3H2O) solution, the AuNPs showed outstanding inhibitory activity against free radicals, -amylase, and AChE. Our work suggests the successful generation of HE-AuNPs, subsequently significant antioxidant, antidiabetic, and anti-Alzheimer agents. However, further study is suggested to minimize potential risks.

Efficient Solid‐State Ultraviolet Emission of 2′,5′‐Dioxy‐p‐terphenyls

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Efficient Solid-State Ultraviolet Emission of 2′,5′-Dioxy-p-terphenyls

Introduction of two alkoxy/siloxy groups at the 2′ and 5′-positions of p-teraryls has been demonstrated to be an effective molecular design strategy for developing fluorophores that exhibit efficient solid-state ultraviolet (UV) emission. The designed p-teraryls emitted UV light in the solid state at wavelengths of 362–391 nm, with quantum yields of 0.20 to 0.46.


Abstract

Organic fluorophores that efficiently emit ultraviolet (UV) light in the solid state are expected to accelerate the development of potentially attractive UV-OLEDs. Herein, we demonstrate that 2′,5′-dialkoxy-, 2′,5′-bis(siloxy)-, and 2′-(alkoxy)-5′-(siloxy)-p-terphenyls and 2,5-dioxy-1,4-(1-naphthyl)benzenes are efficient UV-emitting solid fluorophores. The teraryls were prepared by a Pd-catalyzed Suzuki–Miyaura cross-coupling reaction of readily available 2,5-dialkoxy-1,4-diiodobenzenes with phenyl- and (1-naphthyl)boronic acid, followed by dealkylation–silylation. The dioxy-p-teraryls are thermally stable, with some having glass transition temperatures ranging from −8 to 47 °C. Single-crystal X-ray diffraction analysis of 2′,5′-bis(triphenylsiloxy)- and 2′-(hexyloxy)-5′-(triphenylsiloxy)-p-terphenyls revealed that the terphenyl moieties adopted twisted conformations, and there were no intramolecular π–π interactions in the crystal packing. The terphenyls in CH2Cl2 fluoresced at 370–386 nm with quantum yields of 0.30–0.44. Efficient UV emission (362–391 nm) of the teraryls was observed in the solid state, with quantum yields of 0.20–0.46. Density functional calculations suggest that the optical excitation of the terphenyls involves intramolecular charge transfer from the ethereal oxygen, with the moieties accepting the charge transfer depending on the substituents on the ethereal oxygen atoms.

Sustainable Tailoring of Lignin Nanoparticles Assisted by Green Solvents

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Sustainable Tailoring of Lignin Nanoparticles Assisted by Green Solvents

Lignin nanoparticles (LNPs) can be sustainably produced with green solvents and their properties can be fine-tuned by setting up important parameters, including the order solvent/antisolvent addition, lignin solvent, flow rate, lignin solution loading and washing step. As the best result, homogenous LNPs with average hydrodynamic diameter of 144.4 nm and Zeta potential of −33.2 mV can be obtained with γ-valerolactone.


Abstract

This work aimed at studying the self-assembly of lignin macromolecules towards lignin nanoparticles (LNPs) with green solvents and shedding light on a tailor-made production of LNPs through a meticulous study of different variables. The methodology (antisolvent to lignin solution – method A; or lignin solution to antisolvent – method B), the lignin solvent, the flow rate of solvent/antisolvent addition, the lignin solution loading and the washing step (centrifugation vs dialysis) were examined. Remarkably, method B enabled achieving desired LNPs (127.4–264.9 nm), while method A induced the formation of lignin microparticles (582.8–7820 nm). Among lignin solvents, ethanol allowed the preparation of LNPs with the lowest hydrodynamic diameter (method B=127.4 nm), while the largest particles (method A=7820 nm) were obtained with ethylene glycol. These latest particles were characterized as heterogeneous, irregular, and highly aggregated when compared for instance with γ-valerolactone counterparts, which showed the most homogeneous (PDI=0.057–0.077) and spherical particles. Moreover, decreasing lignin solution loading enabled the reduction on LNP size and Zeta potential. Dialysed samples allowed the formation of LNPs with lower hydrodynamic size, reduced aggregation, and higher homogeneity. Furthermore, dialysis provided high stability to LNPs, avoiding particle coalescent phenomenon.

Synthesis of Silicon and Germanium Oxide Nanostructures via Photonic Curing; a Facile Approach to Scale Up Fabrication

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Synthesis of Silicon and Germanium Oxide Nanostructures via Photonic Curing; a Facile Approach to Scale Up Fabrication

Silicon oxide (SiOx) and germanium oxide (GeOx) nanoparticles are promising candidates for energy storage applications. We synthesized SiOx and GeOx nanostructures by employing photonic curing; a low-cost roll-to-roll instantaneous process. This work is a step to optimize photonic curing for semiconductor oxide nanostructures synthesis on a large scale with nanometric control for next generation energy applications.


Abstract

Silicon and Germanium oxide (SiOx and GeOx) nanostructures are promising materials for energy storage applications due to their potentially high energy density, large lithiation capacity (~10X carbon), low toxicity, low cost, and high thermal stability. This work reports a unique approach to achieving controlled synthesis of SiOx and GeOx nanostructures via photonic curing. Unlike conventional methods like rapid thermal annealing, quenching during pulsed photonic curing occurs rapidly (sub-millisecond), allowing the trapping of metastable states to form unique phases and nanostructures. We explored the possible underlying mechanism of photonic curing by incorporating laws of photophysics, photochemistry, and simulated temperature profile of thin film. The results show that photonic curing of spray coated 0.1 M molarity Si and Ge Acetyl Acetate precursor solution, at total fluence 80 J cm−2 can yield GeOx and SiOx nanostructures. The as-synthesized nanostructures are ester functionalized due to photoinitiated chemical reactions in thin film during photonic curing. Results also showed that nanoparticle size changes from ~48 nm to ~11 nm if overall fluence is increased by increasing the number of pulses. These results are an important contribution towards large-scale synthesis of the Ge and Si oxide nanostructured materials which is necessary for next-generation energy storage devices.

Direct Experimental Observation of the Tetrabromine Cluster Br4 by Synchrotron Photoionization Mass Spectrometry

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Direct Experimental Observation of the Tetrabromine Cluster Br4 by Synchrotron Photoionization Mass Spectrometry

Pure halogens clusters, especially with even numbered molecular formulae, are elusive gas-phase spectroscopic targets. Photoionization mass spectrometry coupled to tunable vacuum-ultraviolet synchrotron radiation allows for the detection and characterization of the tetrabromine Br4 cluster. Based on a joint experimental and computational assessment, Br4 is found to exist as a tetrahedron shape of D2h symmetry.


Abstract

We present a first spectroscopic characterization of the homoatomic polyhalogen tetrabromine, Br4, in the gas phase. Photolysis of CHBr3 at 248 nm is used to generate atomic bromine radicals in a flow tube reactor. Resulting combination products are detected by photoionization mass spectrometry at the Advanced Light Source of the Lawrence Berkeley National Laboratory. Interpretation of the experimental mass spectra is informed by calculated adiabatic ionization energies carried out at the CCSD(T)/aug-cc-pVTZ//M06-2X/aug-cc-pVTZ and CCSD(T)/aug-cc-pVTZ//cam-B3LYP/6-311++g** levels of theory. Tunable VUV synchrotron radiation enables the collection of the mass-selected photoionization spectra by which Br4 is assigned using Franck-Condon simulations of a Br2 dimer with a stretched tetrahedral geometry.

Design, synthesis, and pesticidal activities of novel pyrimidin‐4‐amine derivatives containing trifluoroethyl sulfide moiety

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Design, synthesis, and pesticidal activities of novel pyrimidin-4-amine derivatives containing trifluoroethyl sulfide moiety

By connecting the key intermediate trifluoroethyl sulfide with pyrimidinamine, we obtained T4 with LC50 was 0.19 mg/L against T. urticae and T15 with EC50 was 1.32 mg/L against P. sorghi after active testing and structural optimization.


Abstract

In order to overcome the problem of pesticide resistance, it is necessary to discover novel pesticides with new mechanisms of action. Herein, a series of novel pyrimidin-4-amine derivatives containing trifluoroethyl sulfide moiety were designed and synthesized. Bioassays indicated that the title compounds synthesized possessed excellent acaricidal activity against Tetranychus urticae and fungicidal activity against Erysiphe graminis and Puccinia sorghi. Especially, the acaricidal activity of 5-chloro-6-(difluoromethyl)-N-(2-(2-fluoro-4-methyl-5-((2,2,2-trifluoroethyl)thio)phenoxy)ethyl)pyrimidin-4-amine (compound T4, LC50 = 0.19 mg/L) against T. urticae was close to commercial acaricide cyenopyrafen, and the fungicidal activity of 5-chloro-6-(difluoromethyl)-2-methyl-N-(2-(3-((2,2,2-trifluoroethyl)thio)phenoxy)ethyl)pyrimidin-4-amine (compound T15, EC50 = 1.32 mg/L) against P. sorghi. was superior to commercial fungicide tebuconazole. The synthesis and characterization of these compounds were given and the structure–activity relationships were discussed.

Nanomedicine Disrupts Stromal Barriers to Augment Drug Penetration for Improved Cancer Therapy

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Nanomedicine Disrupts Stromal Barriers to Augment Drug Penetration for Improved Cancer Therapy†

This review summarizes the typical nanostrategies to disrupt tumor stromal barrier for improved cancer therapy, and an up-to-date discussion on some representative studies for deep drug penetration is included, which provides exciting opportunities for designing newly emerging functional biomaterials in this field.


Comprehensive Summary

Tumor stroma composing diverse extracellular matrixes (ECM) and stromal cells shapes a condensed physical barrier, which severely hampers the efficient accessibility of nanomedicine to tumor cells, especially these deep-seated in the core of tumor. Such barrier significantly compromises the antitumor effects of drug-loaded nanomedicine, revealing the remarkable importance of disrupting stromal barrier for improved tumor therapy with deep penetration ability. To achieve this goal, various nanoparticle-based strategies have been developed, including direct depleting ECM components via delivering anti-fibrotic agents or targeting stromal cells to suppress ECM expression, dynamic regulation of nanoparticles’ physicochemical properties (i.e., size, surface charge, and morphology), mechanical force-driven deep penetration, natural/biomimetic self-driven nanomedicine, and transcytosis-inducing nanomedicine. All these nanostrategies were systemically summarized in this review, and the design principles for obtaining admirable nanomedicine were included. With the rapid development of nanotechnology, elaborate design of multifunctional nanomedicine provides new opportunities for overcoming the critical stromal barriers to maximize the therapeutic index of various therapies, such as chemotherapy, photodynamic therapy, and immunotherapy.

Key Scientists

In 2006, Chan et al. demonstrated that the size and shape of nanoparticles were important for biomedical applications, such as intracellular delivery rate and tissue penetration. In addition, the degradation of the structural collagen was confirmed to increase the diffusion of nanoparticles and macromolecules by Davies et al. in 2010. These findings reveal the importance of chemophysical properties of nanoparticles in determining their diffusion and the critical roles of stromal barrier in hindering nanoparticles penetration. On the basis of this, photoswitchable nanoparticles were developed by Kohane et al. for triggered tissue penetration and efficient drug delivery. In 2015, Nie et al. reported the targeted depletion of cancer-associated fibroblasts by peptide assembly for enhanced antitumor drug delivery. In 2019, Shen et al. proposed the transcytosis strategy to promote the tumor penetration of nanoparticles. Very recently, Luo et al. reported the specific reversing of the biological function of cancer-associated fibroblasts to suppress the generation of stromal matrix, greatly increasing the drug perfusion in tumor tissue. All these strategies fueled the design and construction of function-specific nanoparticles for tumor therapy.