Smooth Reaction Research Articles

Copper-Catalyzed Domino Phosphorylation/Cyclization of ortho-Alkynylketones for Accessing Phosphorylated 1H-Isochromenes.

An effective and economical copper-catalyzed approach for the synthesis of phosphorylated 1H-isochromenes is reported. This method is the first example of focus on ketone phosphonylation to establish a C-P bond and 6-endo-dig cyclization to construct a C-O bond between aryl- and alkyl-substituted alkynylketones and H-phosphinate esters, H-phosphites, and H-phosphine oxides, resulting in chemo- and regioselective phosphorylated 1H-isochromenes with moderate to excellent yields under smooth reaction conditions.

Normative Ranges for Oculomotor and Reaction Time Tests in U.S. Military Service Members and Veterans.

Oculomotor and reaction time tests are frequently used assessments of vestibular symptoms, traumatic brain injury (TBI), or other neurological disorders in both clinical and research contexts. When interpreting these tests it is important to have a reference interval (RI) as a comparison for what constitutes a typical/expected response; however, the current body of research has only limited information regarding normative ranges calculated according to established standards or for a military-specific sample. The purpose of the present study was to describe RIs for oculomotor and reaction time tests in a cohort of service members and veterans (SMVs) for use as comparators by clinicians and scientists. Descriptive. Participants were prospectively enrolled in the Defense and Veterans Brain Injury Center-Traumatic Brain Injury Center of Excellence 15-year Longitudinal Traumatic Brain Injury Study. Only SMVs without a history of TBI or blast exposure were included in the RI calculations. The test paradigms included in this analysis were: smooth pursuit, prosaccades, antisaccades, saccades and reaction time, predictive saccades, optokinetic nystagmus, auditory reaction time, and visual reaction time. Nonparametric methods, based on the U.S. Food and Drug Administration's recognized consensus standards, were used to calculate 95% RIs. A comparison between the calculated RIs and those available from previously published research is provided. Summary statistics and RIs were calculated for 47 outcome parameters from 13 oculomotor and reaction time tests. Sample sizes and age ranges varied across outcome parameters depending on the availability of reference values for RI calculations. The sample sizes used to calculate RIs ranged from 51 to 69. The age of SMVs included in each RI ranged from 19 to 61 years with mean ages ranging from 37 to 39 years. Similarities/differences between the RIs in the present study and those in previously published research are highly dependent on the outcome parameter; however, in general, the RIs in the present study tended to be somewhat wider. The RIs provided in this paper can serve as comparisons for clinicians and scientists who are utilizing these oculomotor and reaction time testing paradigms in similar cohorts of patients or research participants.

Synthesis and application of merrifield resin based supported ionic liquids as organocatalyst for the greener synthesis of bio-active triazoles

A green and highly efficient catalysts based on merrifield resin supported acidic ionic liquids (MRBT-SILs) were synthesized using merrifield resin (non-toxic and chemically inert) and benzothiazole. The application of MRBT-SILs for the greener synthesis of 1,2,4-triazole-3-thiones or 1,2,4-triazole-3-oxones from condensation of ketones and thiosemicarbazide or semicarbazide respectively in 60% ethanol under ultra-sonication was studied. The protocol so developed has many additional benefits compared to those reported in previous articles such as smooth reaction, use of alcohol as solvent, good yield, ambient temperature, an easy workup procedure, catalyst recyclability, and high atom economy, making it highly efficient for synthesis as it obeys green chemistry principles. Further, catalyst could be reused up to eight cycles without any loss of its catalytic activity.

Photoresponsive microfluidic three-phase emulsions for tandem reactions

The long-term objective of tandem reaction is to investigate ‘intelligent’ tandem reaction systems akin to living cells. Here we’ve prepared an ‘intelligent’ droplet microreactor for the tandem reaction using droplet microfluidic technology constructing a photoresponsive microfluidic tandem reaction system. The method leverages a three-phase emulsion’s ‘two membranes and three phases’ structure to segregate incompatible reagents, and introduces a stimulating surfactant to control the structure of this emulsion structure for intelligent reaction sequence control, enablingefficient,orderlytandem reactionwithin the same system. Validating this concept, we applied the droplet microreactor to the condensation-reduction cascade reaction, as envisioned, incompatible condensation and reduction reactions, were coordinated by cycling the UV light on /off for a smooth cascade reaction. Compared to batch reaction, the droplet microreactor showed sixfold catalytic efficiency enhancement and > 99 % reaction selectivity. Our work offers novel insights into realizing intelligent cascade reactions.

Thiuram Disulfide Mediated Copper-Catalyzed C–S Cross-Coupling: Synthesis of S-Thiocarbamate Compounds

AbstractThiuram disulfides undergo a Cu(I)-catalyzed C–S cross-coupling with aryl iodides through Cu(OAc)2·H2O-assisted desulfurization to produce the S-thiocarbamate ester compounds efficiently. Various aryl iodides containing diverse substituents underwent a smooth reaction with a series of cyclic and acyclic secondary amine-based thiuram disulfides under an open-air atmosphere. A probable mechanistic pathway has been suggested based on control experiments and reports from the literature.

Coevolution of larval signalling and worker response can trigger developmental caste determination in social insects.

Eusocial insects belong to distinct queen and worker castes, which, in turn, can be divided into several morphologically specialized castes of workers. Caste determination typically occurs by differential nutrition of developing larvae. We present a model for the coevolution of larval signalling and worker task allocation-both modelled by flexible smooth reaction norms-to investigate the evolution of caste determination mechanisms and worker polymorphism. In our model, larvae evolve to signal their nutritional state to workers. The workers evolve to allocate time to foraging for resources versus feeding the brood, conditional on the larval signals and their body size. Worker polymorphism evolves under accelerating foraging returns of increasing body size, which causes selection to favour large foraging and small nursing workers. Worker castes emerge because larvae evolve to amplify their signals after obtaining some food, which causes them to receive more food, while the other larvae remain unfed. This leads to symmetry-breaking among the larvae, which are either well-nourished or malnourished, thus emerging as small or large workers. Our model demonstrates the evolution of nutrition-dependent caste determination and worker polymorphism by a self-reinforcement mechanism that evolves from the interplay of larval signalling and worker response to the signals.

Camphorsulfonic Acid-Catalyzed Synthesis of a Series of 2-Aryl/heteroaryl/alkyl-1H-anthra[ 1,2-d]imidazole-6,11-dione Derivatives

Abstract: Anthraquinone moiety is very common among naturally occurring bioactive compounds. Many commercially available drug molecules also possess anthraquinone moiety. In recent times, among many other anthraquinone derivatives, specifically, 2- substituted-1H-anthra[1,2-d]imidazole-6,11-diones are gaining extra attention due to their significant anti-cancer, anti-HIV, anti-inflammatory activities, etc. This study aimed to report a simple, straightforward, organocatalyzed method for the efficient synthesis of a series of 2-aryl/heteroaryl/alkyl-1H-anthra[1,2-d]imidazole-6,11-diones from the reactions of 1,2-diaminoanthraquinone and various aldehydes using a catalytic amount of camphorsulfonic acid as an efficient organocatalyst in aqueous ethanol under refluxed conditions. Under the same optimized reaction conditions, along with aryl or heteroaryl aldehydes, aliphatic aldehydes also underwent a smooth reaction and afforded the desired products in excellent yields. All the synthesized compounds were obtained pure in excellent yields by simple filtration and washing subsequently with ethanol. The use of less toxic solvent, low-cost, commercially available metal-free organocatalyst, no column chromatographic separation, good yields, and easy isolation procedure are some of the major advantages of this newly developed protocol.

Urchin-Like Mesoporous TiN Hollow Sphere Enabling Promoted Electrochemical Kinetics of Bromine-Based Flow Batteries.

Bromine-based flow batteries (BFB) have always suffered from poor kinetics due to the sluggish Br3 -/Br- redox, hindering their practical applications. Developing cathode materials with high catalytic activity is critical to address this challenge. Herein, the in-depth investigation for the free energy of the bromine redox electrode is conducted initially through DFT calculations, establishing the posterior desorption during oxidation as the rate-determining step. An urchin-like titanium nitride hollow sphere (TNHS) composite is designed and synthesized as the catalyst for bromine redox. The large difference in Br- and Br3 - adsorption capability of TNHS promotes rapid desorption of generated Br3 - during the oxidation process, liberating active sites timely to enable smooth ongoing reactions. Besides, the urchin-like microporous/mesoporous structure of TNHS provides abundant active surface for bromine redox reactions, and ample cavities for the bromine accommodation. The inherently high conductivity of TNHS enables facile electron transfer through multiple channels. Consequently, zinc-bromide flow batteries with TNHS catalyst exhibit significantly enhanced kinetics, stably operating at 80mAcm-2 with 82.78% energy efficiency. Overall, this study offers a solving strategy and catalyst design approach to the sluggish kinetics that has plagued bromine-based flow batteries.

Evaluation of smooth reaction rate of noisy experimental data using Legendre series expansion

Evaluation of smooth reaction rate of noisy experimental data using Legendre series expansion

Molecular Design of Naphthalene- and Carbazole-Based Monomers for Regiospecific Synthesis of Poly(arylenevinylene)s via Co-Catalyzed Hydroarylation Polyaddition.

This study focuses on the development of regiospecific hydroarylation polyaddition of naphthalene- and carbazole-based monomers with diynes under mild reaction conditions at room temperature. A 1-pyrazole substituent serves as an appropriate directing group for a Co-catalyst to efficiently activate the C-H bonds of generally inactive six-membered aromatic hydrocarbons. The 1-pyrazole groups in 2,6-di(1-pyrazolyl)naphthalene adopt planar conformations and act as directing groups, resulting in a smooth hydroarylation reaction. In contrast, the reaction with 1,5-di(1-pyrazolyl)naphthalene do not proceed. The polyaddition reaction of 2,6-di(1-pyrazolyl)naphthalene selectively proceeds at 3,7-positions under mild reaction conditions at 30 °C, and yields corresponding poly(arylenevinylene) (PAV) with high molecular weight. This molecular design is also applicable to the hydroarylation polyaddition of carbazole; the polyaddition reaction of 9-(2-ethylhexyl)-3,6-di(1-pyrazolyl)carbazole selectively occurred at 2,7-positions. The optical and electronic properties of the synthesized compounds are evaluated. The obtained PAVs serve as an emitting material in organic light-emitting diode (OLED). This study aims to develop a Co-catalyzed hydroarylation polyaddition via C-H activation of generally inactive polyaromatic hydrocarbons (PAHs) under mild conditions.

Evaluation of reaction rate of thermogravimetric analysis data using periodic sinc function interpolation

AbstractThe periodic sinc function interpolation offers a compelling solution to address the issue of noise in the analysis of thermogravimetric analysis (TGA) data, thereby enhancing the outcomes of differential techniques such as the Friedman isoconversional method. In this study, we introduce a novel approach that leverages the periodic sinc function interpolation to directly obtain smooth reaction rates from TGA data, eliminating the reliance on numerical differentiation methods. The efficacy of this method has been confirmed through its application to noisy experimental data derived from the thermal decomposition of various polymers, showcasing its robustness. Readers are provided with the corresponding code for Gnu Octave, serving as a free alternative to MATLAB. Additionally, the activation energies calculated from the experimental data using both the Friedman method and periodic sinc function interpolation closely align with those determined by the integral Vyazovkin method, emphasizing the validity and reliability of this new approach.

Simultaneously promoting the surface/bulk structural stability of Fe/Mn-based layered cathode for sodium ion batteries

Layered sodium iron manganese oxide cathodes have attracted great interest owing to their high specific capacity and cost-effective metal resources, while the detrimental phase transitions and surface structural degradation severely limit their commercial applications. In this work, the bulk and surface structure stability of a P2-Na0.67Fe0.5Mn0.5O2 cathode can be synergically enhanced by a one-step Li/Nb co-doping strategy. Structural characterizations reveal that Li doping promotes the formation of P2/O3 biphasic structure and makes the unfavorable P2-OP4 phase transition convert into a smooth solid-solution reaction. Nb doping enhances the mobility of sodium ions and forms strong Nb-O bonds, thereby enhancing the stability of the TMO2 layer structure. In particular, the Nb element induces the surface reorganization of an atomic-scale NaNbO3 coating layer, which could effectively prevent the dissolution of metals and surface side reactions. The synergistic mechanism of enhanced electrochemical performance is proved by multiple characterizations during cycling. As a result, the as-prepared Na0.67Li0.1Fe0.5Mn0.38Nb0.02O2 exhibits improved capacity retention of 85.4 % than raw material (45.7 %) after 100 cycles at 0.5C (1C = 174 mA g−1) within 2.0–4.0 V. This co-regulating strategy provides a promising approach to designing highly stable sodium-ion battery cathodes. Furthermore, a full cell of Na0.67Li0.1Fe0.5Mn0.38Nb0.02O2 with hard carbon displays excellent cycling stability (85.1 % capacity retention after 100 cycles), making its commercial operation possible. This synergistic strategy of biphasic structure and surface reorganization is a critical route to accelerate the application of layer oxide cathodes.

Towards an efficient oxidation of sulfides to sulfoxides over magnetic and grafted polyoxometalate on graphene oxide nanosheets

In this study, a tri-component composite consisting of Fe3O4 nanoparticles, Keggin-type polyoxometalate, and graphene oxide components was prepared using an ultrasonic-assisted method. The resulting Fe3O4/SiW12/GO composite was successfully characterized using multiple methods. The performance of the Fe3O4/SiW12/GO composite as a heterogeneous catalyst for the oxidation of sulfides to sulfoxides was investigated under mild conditions, with H2O2 serving as the oxidant. The catalyst exhibited excellent stability and high yields, completing the conversions within one hour. Furthermore, the Fe3O4/SiW12/GO catalyst demonstrated remarkable recyclability, as it could be recovered and reused up to four times without any significant loss in activity. This finding was supported by the results obtained from the ICP-OES analysis, which confirmed the negligible leaching of the active site. One of the key advantages of the Fe3O4/SiW12/GO catalyst is its heterogeneous nature, which allows for its rapid recovery from the reaction mixture. Additionally, it offers smooth and clean reaction conditions at room temperature, making it an innovative and cost-effective choice for accelerating reaction times. In summary, the Fe3O4/SiW12/GO composite represents a highly efficient and versatile heterogeneous catalyst with a unique structure. Its exceptional stability, high yields, and recyclability make it a superior choice for various organic–inorganic hybrid catalytic reactions conducted under mild conditions.

Quasi‐synchronous solid‐state reaction for cordierite powder synthesis

AbstractThis study investigates a quasi‐synchronous solid‐state reaction for synthesizing cordierite powder using talc, kaolinite, and Al2O3 mineral powders as starting materials. The thermal reaction proceeded with two different stages according to the Al sources provided by: (1) Al2O3 powders—the first stage starting at temperatures that were considerably lower than 1150°C and (2) kaolinite (mullite)—the second stage starting at temperatures that were higher than 1150°C. The goal is to shift the temperature of the first stage to coincide with that of the second stage by mixing α‐cordierite powder with the starting constituents. Exceeding the authentic reduction amounts of Al2O3 on talc particles leads to a rise in the temperature required to initiate the first‐stage reaction to 1200°C. However, this also eliminates the presence of β‐cordierite and spinel that occur in the first stage and allows for the early fulfilment of α‐cordierite formation in the second stage. The excess SiO2 released by the second stage compensates for the insufficient SiO2 required by the first stage, allowing for a smooth processing reaction. Also, a quasi‐synchronous solid‐state reaction for synthesizing cordierite occurs.

Effects of carbon vacancies on the CO oxidation on Cu double atom catalyst supported by graphene

The activity of double metal atoms is closely related to their chemical coordination environments. In this work, CO oxidation on Cu double atom catalyst loaded on defective graphene with triple carbon vacancy (Cu2-TG) and quadruple carbon vacancy (Cu2-QG) has been comprehensively studied through DFT calculations. Empty Cu-3d orbital is created through charge transfer from Cu atom to carbon atom of graphene, which is parallel to the basal plane of graphene for one Cu atom and nearly perpendicular to the basal plane for the other Cu atom in Cu2-TG. While the empty Cu-3d orbital is parallel to the basal plane for both Cu atoms in Cu2-QG. The delocalized orientation of empty Cu-3d orbital in Cu2-TG makes it more convenient to accept electrons and more active. This is verified through the larger adsorption energies of -1.74 eV and -1.68 eV for O2 and CO molecules on Cu2-TG, as well as the smaller values of -0.20 eV and -0.40 eV on Cu2-QG, respectively. Because of the weak interactions between Cu2-QG and gas molecules, only Cu2-TG is further considered to catalyze the CO oxidation. The maximum barrier of CO oxidation along ER path is 1.75 eV on Cu2-TG, while that is only 0.39 eV along LH path, which indicates a smooth reaction progress on Cu2-TG. The electronic structures show that the Cu atom can accept electrons through its empty 3d orbital and lose electrons through its filled 3d orbital with an “acceptance and feedback” mechanism. Cu2-TG can move the 5σCO orbital downshift significantly, which causes the 5σCO/1πCO orbitals very close to 5σO2/1πO2 orbitals and facilitates the formation of OC-OO bond along LH path. These results indicate that the synergistic effects between the two Cu atoms and the triple carbon vacancy make Cu2-TG to be an efficient CO oxidation catalyst.

In Situ Generation of Magnesium- and Calcium-Based Grignard Reagents for Amide Synthesis.

The alkaline-earth metals Mg and Ca are too inert for the direct metalation of primary and secondary amines. Consequently, activation prior to use is required. Alternatively, the Grignard reagents RMgX (R=alkyl, aryl, X=halide) can be applied in metalation of amines. However, such a straightforward procedure for the synthesis of alkylcalcium reagents is disadvantageous due to diverse side reactions, including Wurtz-type C-C coupling and ether degradation reactions. Therefore, suspensions of magnesium or calcium with amine can be treated in a smooth reaction with ethyl bromide in an ethereal solvent at room temperature. Intermediately formed RAeX (Ae=alkaline-earth metal, i. e., Mg, Ca) either metalates amines yielding the corresponding amides in an in situ Grignard metalation method (iGMM) or adds across C=N bonds of imines in an in situ Grignard addition method (iGAM). The amides R'2 N-AeX (Ae=Mg: Hauser bases) undergo Schlenk-type ligand exchange reactions yielding homoleptic Ae(NR'2 )2 and potentially sparingly soluble AeX2 .

Enhanced conversion reaction of Na-Cu-PO3 via amorpholization and carbon-coating for large Na storage

Conversion-type cathodes have a higher theoretical capacity compared to intercalation-type cathodes due to the use of more transition metal cations. However, their sluggish kinetics and low operation voltage hinder their practical application in the industry, resulting in low specific capacity. To address these issues, we prepare an amorphous carbon-coated Cu(PO3)2 nanocomposite, and evaluate its electrochemical performance under rechargeable Na-ion battery system. At a current density of 24 mA/g, it achieves a large specific capacity of ∼232 mAh/g with an average operation voltage of ∼2.0 V (vs. Na+/Na). Furthermore, the amorphous carbon-coated Cu(PO3)2 nanocomposite exhibits a cycle retention of ∼90% compared to the initial capacity after 100 cycles. In contrast, bare Cu(PO3)2 shows poor electrochemical performance under the same conditions. Various experimental measurements have demonstrated that the amorphous carbon-coated Cu(PO3)2 nanocomposite exhibits a reversible and smooth conversion reaction of Cu(PO3)2 phase in the rechargeable Na-ion battery system.

One-Pot Synthesis of 3-Substiuted Indoles from 2-(2-Nitro-1-phenylethyl)cyclohexanone Derivatives

Herein, a one-pot synthesis of 3-substituted indoles from 2-(2-nitro-1-phenylethyl)cyclohexanone derivatives catalyzed by Pd/C is reported. The starting materials can be easily prepared by the reaction of substituted ketones and nitroalkenes. The facile experimental procedure comprises the treatment of 2-(2-nitro-1-phenylethyl)cyclohexanone derivatives with H2 as a hydrogen donor in the presence of 10 mol % Pd/C. Subsequently, the exchange of H2 with CH2═CH2 as a hydrogen acceptor affords a variety of 3-substituted indoles in high yields. The formation of intermediate nitrones is essential for a smooth reaction.

Electrochemical Sensor Based on Co-Doped FePS3 Nanosheets for Ultra-Sensitive Detection of Dopamine in Human Serum

Electrochemical dopamine (DA) sensors become important for the early diagnosis of psychiatric disorders like schizophrenia and Parkinson’s disease due to their fast response, simplicity, and portability. However, traditional electrode modification materials such as noble metals and metal oxides have shortcomings such as high cost, low conductivity, or limited catalytic performance. Two-dimensional sulfide materials contribute to the smooth electrode reaction because of their ultra-high specific superficial area and favorable electrocatalysis properties, however, their low carrier mobility and poor electroconductibility limit the detection signal. In this paper, Co-doped FePS3 nanosheets were employed for DA detection for the first time. Fe0.9Co0.1PS3 nanosheets exhibited a detection limit of 120 nM, a linear range 0.25–100 μM and 120–500 μM, and possessed high recovery and reproducible stability when applied to human serum samples. Furthermore, according to the in situ XPS characterization, S atoms located on the outmost layer of Fe0.9Co0.1PS3 nanosheets could be combined with the phenolic hydroxyl oxygen of DA, which makes electrode reaction from DA to dopamine quinone easier. Co-doping can further enhance the above effect, and increase the carrier mobility of FePS3 nanosheets. This work demonstrated electrochemical sensors based on metal phosphorus trisulfide materials have tremendous potential for future application in mental disorder diagnosis.

Fabrication of novel thin-film composite membrane based on ultrathin metal-organic framework interlayer for enhancing forward osmosis performance

To improve operation efficiency, an interlayered thin-film composite forward osmosis (iTFC-FO) membrane was designed by introducing an ultrathin and porous interlayer based on aluminum tetra-(4-carboxyphenyl)porphyrin (a stable metal−organic framework nanosheet, Al-MOF). Surface characterization results revealed that Al-MOF spread evenly in the macro-porous substrate, and provided a flat and smooth reaction interface with moderate hydrophilicity and uniform small aperture. The resultant polyamide (PA) layer had a thin base (without intrusion into substrate) and crumpled surface (with abundant leaves). The leaves size and cross-linking degree of PA layer firstly increased and then decreased with the Al-MOF loading. Compared to the original membrane, the iTFC-FO showed an enhanced water permeability and a reduced reverse sodium flux in both modes of active layer facing feed solution (AL-FS) and active layer facing draw solution (AL-DS). To be specific, the specific reverse sodium flux (reverse sodium flux/pure water flux) decreased from 0.27 g/L to 0.04 g/L in the AL-FS mode, while from 1.36 g/L to 0.23 g/L in the AL-DS mode with 2 mol/L NaCl as DS. Moreover, the iTFC-FO maintained high stability and high permeability under high-salinity and contaminated environment. This study offers a new possibility for the rational fabrication of high-performance TFC-FO membranes.