Search

We propose an efficient algorithm for a minimum free energy path calculation based on the path integral hybrid Monte Carlo (PIHMC) method by combining the climbing image-nudged elastic band (CI-NEB) and the thermodynamic integration (TI) methods. Here, the CI-NEB and the TI methods are used to find a transition state along the reaction path and evaluate the free energy path, respectively. Our algorithm is applied to the Walden inversion reaction of the hydronium ions (H3O+). The numerical results show that the computational effort by our algorithm is significantly reduced compared to that of the previously proposed algorithm combining PIHMC without losing accuracy. We also demonstrate the importance of temperature and isotope effects on the addition reaction of hydrogen isocyanide to formaldehyde. In this reaction, the nuclear quantum effect causes the structural change at the TS and decreases the energy barrier. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) and NO–water clusters play crucial roles in the D-region of the atmosphere because it is postulated that NO+ reacts with H2O to produce nitrous acid (HONO) and H3O+. HONO is the major precursor of the hydroxyl radicals leading to the formation of secondary pollutants. The sources of atmospheric HONO, however, are not fully understood. Previously, the sequential H2O addition reaction, H2O + NO+(H2O)n, and the bi-molecular collision reaction, NO+ + (H2O)n, have been investigated by both experiments and theoretical calculations to determine the formation mechanism of HONO. However, the photo-reactions from NO(H2O)n neutral clusters were not considered for the formation mechanism of HONO. In this study, the intra-cluster reactions of NO+(H2O)n clusters, following ionization of the parent neutral cluster of NO(H2O)n, were investigated using the direct ab initio molecular dynamics method. When n = 4, [NO+(H2O)4]ver [vertical ionization state of NO(H2O)n] yielded HONO and hydrated H3O+ after the intra-cluster reaction, and the reaction time was calculated to be 150 fs. The reaction is expressed as [NO+(H2O)n]ver → HONO + H3O+(H2O)n−2 (reactive) (n > 3). Larger clusters of [NO+(H2O)n]ver (n = 5–8) also yield HONO. In contrast, in smaller clusters (n = 1–3), only solvent re-orientation around NO+ occurred after the ionization: [NO+(H2O)n]ver → NO+(H2O)n (solvent re-orientation) (n = 1–3). The hydration energy of H3O+, which depends on the cluster size (n), plays an important role in promoting the formation of HONO. The reaction mechanism is discussed based on theoretical results. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) and NO–water clusters play crucial roles in the D-region of the atmosphere because it is postulated that NO+ reacts with H2O to produce nitrous acid (HONO) and H3O+. HONO is the major precursor of the hydroxyl radicals leading to the formation of secondary pollutants. The sources of atmospheric HONO, however, are not fully understood. Previously, the sequential H2O addition reaction, H2O + NO+(H2O)n, and the bi-molecular collision reaction, NO+ + (H2O)n, have been investigated by both experiments and theoretical calculations to determine the formation mechanism of HONO. However, the photo-reactions from NO(H2O)n neutral clusters were not considered for the formation mechanism of HONO. In this study, the intra-cluster reactions of NO+(H2O)n clusters, following ionization of the parent neutral cluster of NO(H2O)n, were investigated using the direct ab initio molecular dynamics method. When n = 4, [NO+(H2O)4]ver [vertical ionization state of NO(H2O)n] yielded HONO and hydrated H3O+ after the intra-cluster reaction, and the reaction time was calculated to be 150 fs. The reaction is expressed as [NO+(H2O)n]ver → HONO + H3O+(H2O)n−2 (reactive) (n > 3). Larger clusters of [NO+(H2O)n]ver (n = 5–8) also yield HONO. In contrast, in smaller clusters (n = 1–3), only solvent re-orientation around NO+ occurred after the ionization: [NO+(H2O)n]ver → NO+(H2O)n (solvent re-orientation) (n = 1–3). The hydration energy of H3O+, which depends on the cluster size (n), plays an important role in promoting the formation of HONO. The reaction mechanism is discussed based on theoretical results. [ABSTRACT FROM AUTHOR]

The chemistry of platinum(II) and platinum(IV) with the ligands 3,4,5-tris(2-pyridyl)-4-H-1,2,4-triazole, L1, and 3,5-di(2-pyridyl)-4-(4-pyridyl)-4-H-1,2,4-triazole, L2, is described. The ligand L1 forms platinum(II) complexes [PtXY(κ2-N, N′-L1)] (X, Y = Cl, Cl; Cl, Me; Me, Me) by chelation while ligand L2 forms either analogous chelate complexes [PtXY(κ2-N, N′-L2)] (X, Y = Cl, Me; Me, Me) or acts as a monodentate ligand in forming trans-[PtCl2(SMe2)(κ1-N-L2)], in which only the 4-pyridyl group is coordinated. The electron-rich dimethylplatinum(II) complexes undergo oxidative addition reactions with methyl iodide to give [PtIMe3(κ2-N, N′-L1)], or with dichloromethane to give [PtClMe2(CH2Cl)(κ2-N, N′-L1)] or [PtClMe2(CH2Cl)(κ2-N, N′-L2)], each of which is formed as a mixture of three isomers. Structure determinations of several of these complexes are reported. [ABSTRACT FROM AUTHOR]

A dichloro(2‐pyridinecarboxylato)gold complex anchored on SBA‐15 (SBA‐15‐PicAuCl2) was conveniently prepared through the addition reaction between triethoxy(3‐isocyanatopropyl)silane and dichloro(3‐hydroxy‐2‐pyridinecarboxylato)gold complex and subsequent condensation with SBA‐15. The new heterogenized PicAuCl2 complex was fully characterized by using various analytic methods. In the existence of 5 mol% of SBA‐15‐PicAuCl2, the regioselective [3 + 2] cycloaddition reaction between ynamides and pyridine‐N‐aminides proceeded in toluene at 100°C for 1–24 h to deliver a wide array of functionalized trisubstituted 1,3‐oxazoles in 57%–95% yields. Ynamides with alkyl, benzyl, and aryl substituents as well as different sulfonyl groups at the nitrogen atom and the oxazolidinone‐derived ynamides were well‐tolerated. A wide range of pyridine‐N‐aminides bearing aroyl, naphthoyl, furoyl, vinylcarbonyl, alkylcarbonyl, and methoxycarbonyl were also allowed in the reaction. Moreover, SBA‐15‐PicAuCl2 is easy to recover through a simple centrifugation and recyclable at least seven cycles with only a slight drop in catalytic activity. [ABSTRACT FROM AUTHOR]

A series of fused heterocyclic compound triazolotetrazine were prepared from the reaction of equimolar amount of 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol via cyclization addition reaction with different aromatic aldehydes in presence of piperidine as catalyst to produce the target [1,2,4]triazolo[4,3- b][1,2,4,5] tetrazine derivatives. The synthesized compounds were characterized by spectral methods (FT-IR and 1H-NMR, 13C-NMR and mass). The newly synthesized compounds exhibited an anticancer effect when these compounds were docked inside the C-Met tyrosine kinase receptor. As shown by their docking scores, they range from -5.599 to -4.403 Kcal/mol, whereas Crizotinib binding affinity is -3.211 Kcal/mol. For antibacterial efficiency, 4e and 4f testing on a series of bacteria, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, and Klebsiella, respectively, reveals that the compounds have exhibited moderate activity against negative and positive bacteria. Antifungal activity of (4g, 4i) was assessed against the representative typical fungi such as Candidiasis fungal and compared with Fluconazole as an antifungal drugs. The results indicated that tested compounds had good fungicide activity, which has good growth inhibition against Candidiasis [ABSTRACT FROM AUTHOR]

Electrochemical in situ modification of graphene remains a challenge because of the pretty low concentration of radicals generated during the electroexfoliation process. The spatially confined electrosynthesis of halogen‐poor and carbonyl‐rich graphene (XCG, X═F, Cl, Br) is reported. It is found that the effective radical addition reaction between graphite/graphene and electro‐generated radicals (halogen radical and carboxylic radical) is promoted by using X− and HCOO− as both intercalation ions and co‐reactants, which assists the efficient formation of high crystalline XCG. The assembled XCG membrane exhibited high interception for NaCl, KCl, MgCl2, and K2SO4 due to the narrow interlayer space. Theoretical calculations revealed favorable water migration on surface of F atoms, thus grasping the high water permeation. Furthermore, the halogen and carboxyl functional groups afforded XCG highly efficient water splitting. The current work highlights the in situ modification of graphene during the electroexfoliation process and the subsequent applications in membrane science, molecular engineering, and other energy‐related applications. [ABSTRACT FROM AUTHOR]

Bio‐inspired unidirectional flow of tiny aqueous droplets across the fibrous substrate paved the way for the emergence of various advanced materials. In the past, textiles decorated with noncontact‐based wettability‐patterns enabled unidirectional water flow—without flooding the top surface by the transferred water. However, such approaches mostly suffer from a low (≈0.176 µL mm−2 s−1) flow rate and are likely to delay the overall liquid ejection process. Here, a chemically reactive coating capable of tailoring water wettability (121.3° ± 2.4° to 153.3° ± 1.8°) is introduced on commercially available textiles to develop chemically modulated wettability‐pattern for achieving a rapid (2.57 ± 0.28 µL mm−2 s−1) flow rate of water against the gravity with an ability to roll the accumulated liquids on the top surface. The spatially selected and controlled chemical modification with hydrophilic and hydrophobic small molecules through a 1, 4‐conjugate addition reaction yielded a 3D channel with a customized wettability gradient. The pinning and depinning of invaded water through such chemically decorated channels enabled unidirectional and fast penetration of liquid, where the water penetration resistance largely depends on the water penetration direction and dimension of the chemically modulated channels. [ABSTRACT FROM AUTHOR]

Bimetallic (Ta/Ti, V, Co, Nb) mesoporous MCM-41 nanoparticles were obtained by direct synthesis and hydrothermal treatment. The obtained mesoporous materials were characterized by XRD, XRF, N2 adsorption/desorption, SEM, TEM, XPS, Raman, UV-Vis, and PL spectroscopy. A more significant effect was observed on the mesoporous structure, typically for MCM-41, and on optic properties if the second metal (Ti, Co) did not belong to the same Vb group with Ta as V and Nb. The XPS showed for the TaTi-MCM-41 sample that framework titanium is the major component. The new nanoparticles obtained were used as catalysts for oxidation with hydrogen peroxide of olefinic compounds (1,4 cyclohexadiene, cyclohexene, styrene) and photodegradation of organic pollutants (phenol, methyl orange) from water. The results showed improvementsin activity and selectivity in oxidation reactions by the addition of the second metal to the Ta-MCM-41 catalyst. The slow addition of H2O2 was also beneficial for the selectivity of epoxide products and the stability of the catalysts. The band gap energy values decreased in the presence of the second metal, and the band edge diagram evidenced positive potential for all the conduction bands of the bimetallic samples. The highestlevels of photocatalytic degradation were obtained for the samples with TaTi and TaV. [ABSTRACT FROM AUTHOR]

Reversible addition−fragmentation chain transfer (RAFT) polymerization has been one of the most versatile methods in the synthesis of well‐defined polymers. The stability of the thiocarbonylthio chain transfer agents (CTAs) in the polymerization and the removal of CTAs after the polymerization are the two great concerns for the applications of RAFT polymerization. In this research, thiol‐dithioester reaction under the catalysis of triethylamine (TEA) is studied. In a model reaction, thiolate anion has nucleophilic addition reaction with dithioester compound, resulting in the synthesis of a new dithioester and a new thiol compound. The effects of TEA to dithioester molar ratio and reaction time on the yield of the product are investigated. The application of thiol‐dithioester reaction in the removal of end CTAs from polymer chains is studied. 1H NMR, UV–vis, and size‐exclusion chromatography (SEC) results all demonstrate the effective removal of CTAs and the generation of thiol groups at polymer chain ends. The thiol groups can be further used for the terminal functionalization of polymers. In this research, alkyne‐terminated poly(methyl methacrylate) and FMOC‐l‐Cys‐labeled poly(di‐[ethylene glycol] methyl ether methacrylate) are synthesized by TEA‐catalyzed thiol‐ene reaction and thiol‐disulfide reaction, respectively. Thiol‐dithioester reaction provides an effective approach to the removal of CTAs and end functionalization of RAFT synthesized polymers. [ABSTRACT FROM AUTHOR]

Phenylacetylene plays a critical role as an intermediate in PAH formation in hydrocarbon flames. In this work, the autoignition characteristics of phenylacetylene were investigated behind reflected shock waves. Ignition delay times were measured at temperatures ranging from 1228 to 1813 K, pressures of 2, 4, and 10 atm, equivalence ratios of 0.5, 1.0, and 2.0, as well as fuel mole fractions of 0.1% and 0.2%. The effects of temperature, pressure, equivalence ratio, and mole fractions on ignition delay time were investigated, and quantitative relationships were obtained by regression analysis of the experimental data. A detailed oxidation mechanism of phenylacetylene based on NUIGMech1.1 was proposed and verified using ignition data. Reaction pathway and sensitivity analyses have been carried out to investigate the significant reaction pathways in the ignition process and key reactions that affect the ignition delay time. The addition reactions by O and OH species contribute significantly to phenylacetylene consumption and promote fuel ignition. Finally, a comparison of the ignition delay times of ethylbenzene, styrene, and phenylacetylene was conducted in this study, and kinetic analyses have been conducted to investigate the impact of different side chains attached to aromatic rings on the ignition of these C8 aromatics. [ABSTRACT FROM AUTHOR]

A synthetic method of tertiary alcohols was developed based on the formal umpolung addition of aryl ketones with electrophiles utilizing the [1,2]‐phospha‐Brook rearrangement under Brønsted base catalysis. The addition reaction of α‐hydroxyphosphonates, derived from alkyl aryl‐ and diaryl ketones, with electrophiles such as phenyl vinyl sulfone, afforded phosphates having a tertiary alkyl group, which were readily convertible to the corresponding tertiary benzylic alcohols. This operationally simple protocol provides efficient complementary access to tertiary alcohols that are difficult to synthesize by conventional methods. [ABSTRACT FROM AUTHOR]

The ability to change the essential characteristics of the molecular systems using light is highly promising and finds use in photocatalysis and materials chemistry. A critical requirement for such systems is that molecules should directly absorb light in the visible region. Though small molecule activation by visible light is challenging, they on complexation with certain species respond to visible light favourably. Herein, we disclose the catalytic application of CBr4 as a halogen bond donor catalyst to activate para‐quinone methides towards visible light photo‐catalysed reactions. This protocol facilitates 1,6‐conjugate addition reactions with various nucleophiles, forming C−C and C−O bonds in para‐quinone methides, yielding the desired products in good to excellent yields. Mechanistic investigations reveal that para‐quinone methide responds to visible light only when complexed with CBr4. The synthetic utility of this protocol is demonstrated through the one‐pot synthesis of spiro‐cyclohexadienone compounds from 2‐naphthol and para‐quinone methide. [ABSTRACT FROM AUTHOR]

Electrochemical transformations are considered a green alternative to classical redox chemistry as it eliminates the necessity for toxic and waste producing redox reagents. Typical electrochemical reactions require the addition of a supporting electrolyte – an ionic compound to facilitate reaction medium conductivity. However, this is often accompanied by an increase in the amount of produced waste. Here, we report an "in‐situ electrolyte" concept for facile, transition‐metal‐free, additive‐free one‐pot electrochemical preparation of isoxazol(in)es, important scaffolds for biologically active natural and synthetic molecules, from the respective aldehydes. The protocol utilizes no halogenated solvents and no external oxidants, while salt side‐products provide the ionic conductivity necessary for the electrosynthesis. The electrolysis is performed in an undivided cell, using the state‐of‐the‐art electrodes for the chlor‐alkali industry dimensionally stable and scalable mixed metal oxide anode and platinized titanium cathode of high durability. The cascade transformation comprises the condensation of aldehyde to oxime followed by its anodic oxidation and subsequent intra‐ and/or intermolecular [3+2] cycloadditions with an appropriate dipolarophile. Chemical yields up to 97 %, and good Faradaic efficiency, scalability, and stability are observed for most substrates in a broad scope. [ABSTRACT FROM AUTHOR]

Over the past decade, significant research efforts have focused on osmapentalyne, characterized by the more reactive Os≡C7 (Carbon atoms numbered in a clockwise direction on the osmapentalyne skeleton), across areas encompassing electrophilic, nucleophilic, and addition reactions. Nevertheless, the reactivity of osmapentalyne featuring Os≡C1 remains ripe for further exploration. In this investigation, we effectively synthesized a lineage of osmapentalenofurans through the nucleophilic reaction of osmapentalyne incorporating Os≡C1 with phenols. These resulting complexes demonstrate near‐infrared luminescence traits in both solid and liquid states. Particularly noteworthy is the osmapentalenofuran derived from tetraphenylethane (TPE) unit, which showcases remarkable aggregation‐induced emission (AIE) property in the aggregated state. These osmapentalenofurans are also able to further extend their range of reactions, including reactions with base and isonitrile. This study not only broadens the scope of applications for metal aromatics but also furnishes valuable insights into the realm of specialized functional materials. [ABSTRACT FROM AUTHOR]

The dimeric calcium and magnesium hydrides, [(BDI)AeH]2 [BDI=HC{(Me)CNDipp}2, Dipp=2,6‐i‐Pr2C6H3; Ae=Mg or Ca] do not react with Ph3GeH in non‐coordinating solvent. Addition of THF, however, induces deprotonation and access to monomeric Ae‐germanide complexes, [(BDI)Ae{GePh3}(THF)], both of which have been structurally characterized. Although this process is facile when Ae=Ca, the analogous magnesium‐based reaction requires heating to temperatures >100 °C, under which conditions germanide formation is complicated by THF ring opening and the generation of an alkaline earth germyl‐C‐terminated n‐butoxide, [(BDI)Mg{μ2‐O(CH2)4GePh3}]. Reactions of [(BDI)Ca{GePh3}(THF)] with N,N′‐di‐isopropylcarbodiimide and benzophenone provide the respective germylamidinate and germylalkoxide derivatives, [(BDI)Ca{(i‐PrN)2CGePh3}(THF)] and [(BDI)Ca{OC(GePh3)Ph2}(THF)], demonstrating its potential as a well‐defined and soluble source of the [Ph3Ge]− anion in nucleophilic addition reactions. [ABSTRACT FROM AUTHOR]

The oxygen initiation process, one of the key processes in the early stage of the autothermic pyrolysis insitu conversion technology, has not been deeply investigated, which seriously limits its development. In this study, the reaction behaviors, kinetic parameters, heat and product release characteristics during the isothermal oxygen initiation process of Huadian oil shale in O2/N2 mixtures with different oxygen concentrations and initiation temperatures were investigated via TG/DSC-FTIR. The results show that the samples exhibit three different reaction behaviors during the initiation stage, consisting of two main parts, i.e., the oxidative weight-gain and the oxidative reaction phases. The former phase is mainly characterized by the oxygen addition reaction that produces oxidizing groups which increase the sample mass. And the latter stage consists of two main subreactions. The first subreaction involves the oxidative cracking and pyrolysis of oxidizing groups and kerogen to produce fuel deposits such as residual carbon, while the second subreaction focuses on the oxidation of the resulting fuels. Furthermore, increasing the oxygen concentration significantly promotes the above reactions, leading to an increase in the reaction intensity and reaction rate. Owing to the combined effect of oxygen concentration and residual organic matter content, the total heat release increases with the increasing initiation temperature and reaches its maximum at 330e370°C. In addition, the preheating stage primarily produces hydrocarbon gases, while the initiation stage predominantly generates CO2. As the preheating temperature increases, the CO2 output intensifies, the required reaction time shortens, and the release becomes more concentrated. Based on these findings, a reaction mechanism for the oxygen initiation process of Huadian oil shale was proposed, and recommendations were provided for optimizing the construction process. [ABSTRACT FROM AUTHOR]

1-Methylnaphthalene is a critical component for constructing fuel surrogates of diesel and aviation kerosene. However, the reaction pathways of 1-methylnaphthalene included in existing detailed chemical kinetic models vary from each other, leading to discrepancies in the simulation of ignition and oxidation processes. In the present study, reaction classes and pathways involved in the combustion of 1-methylnaphthalene were analyzed, and effects of rate constants of reactions related to 1-methylnaphthalene and its significant intermediates on ignition delay times and species concentration profiles were discussed, involving hydrogen abstraction and substitution reactions of 1-methylnaphthalene, oxidation, isomerization, and addition reactions of 1-naphthylmethyl, hydrogen abstraction and oxidation reactions of indene, as well as the oxidation of indenyl and naphthalene. On this basis, a new detailed chemical kinetic model for 1-methylnaphthalene was developed, which includes 1389 species and 7185 reactions. The validation of this mechanism shows that it can predict accurately the available experimental ignition delay times, species concentration profiles, and laminar flame speeds of 1-methylnaphthalene. Finally, reaction paths and sensitivity analysis of ignition delay times were performed using the proposed reaction mechanism, and the result shows that the conversion of 1-methylnaphthalene to 1-naphthaldehyde plays an important role in its ignition. [ABSTRACT FROM AUTHOR]

Poly(β‐amino ester) (PβAE)‐based polymers hold promise for bacterial gene transfer due to their ability to form stable complexes with genetic material and facilitate efficient delivery into bacterial cells. These polymers are easily modified to improve uptake and protect DNA or RNA from degradation, providing a safer, more controlled alternative to traditional methods like chemical transformation or electroporation. In this study, we evaluated the gene transformation efficiency of cationic PβAE polymer, which was synthesized through an aza‐Michael addition reaction between piperazine and poly(ethylene glycol) diacrylate. Competent cells from E. coli strain DH5α were prepared with the optimized method using Ca2+ and Mg2+ ions. Different concentrations of the polymer were mixed with pRSET‐EmGFP before transforming into competent cells through the heat shock method. Transformed cells were checked on medium containing ampicillin, and by using colony PCR, transformation efficiency was calculated. Based on our findings, we observed a successful transformation of the EmGFP gene in case of having the polymer. Furthermore, the PβAE at high concentrations (20–100 ng µL−1) increased transformation efficiency more than twice as compared to the case of no polymer added. In conclusion, PβAE can effectively increase transformation efficiency. [ABSTRACT FROM AUTHOR]

Prins reaction of isoprenol with butanal provides important intermediate 4-methyl-2-propyltetrahydro-2H-pyran-4-ol, which can be esterified to 4-methyl-2-propyltetrahydro-2H-pyran-4-yl acetate. This desired fragrance with fruity and rose scent is known, e.g., as Clarycet®. Molybdenum-modified MCM-41 materials were obtained by a wet impregnation method using a water solution of ammonium molybdate. We prepared several materials with different MoO3 loadings. These materials were thoroughly characterized (nitrogen physisorption, acidity—temperature-programmed desorption, elemental composition, etc.). The activity of prepared materials was tested in Prins reaction of isoprenol with butanal in batch arrangement. The influence of various reaction conditions (catalyst type, solvent, and water addition) was tested. We showed that modification of MCM-41 with MoO3 led to a significant increase of catalytic activity (butanal conversion at 4 h of reaction: 7% for nonmodified MCM-41 compared to 93% for material 5 wt% of MoO3-MCM-41). Water addition to the reaction mixture positively influenced the selectivity of the desired substituted tetrahydropyranol (selectivity > 70%). Mo-modified materials were also active in the esterification of 4-methyl-2-propyltetrahydro-2H-pyran-4-ol with acetanhydride to 4-methyl-2-propyltetrahydro-2H-pyran-4-yl acetate providing desired product after 5 h with 100% selectivity and total conversion. Reaction in the "one-pot" arrangement was also performed. [ABSTRACT FROM AUTHOR]

Methotrexate (MTX) is a chemotherapy agent and immune system suppressant that is widely used to treat a variety of malignant and nonmalignant diseases. Due to some drawbacks of the existing methods for the determination of MTX in aquatic and real samples, we prepared a new, simple, and selective dual‐mode fluorometric and electrochemical approach based on peroxidase‐mimic [Mo36] polyoxomolybdate nanoclusters (POMo) for sensing MTX. A turn‐on–off fluorometric approach for the detection of MTX was developed, which was based on the inhibition of the emission intensity of the terephthalic acid (TA)‐H2O2 system upon the addition of MTX to the reaction solution. The electrocatalytic performance of the obtained POMo was studied after making a carbon paste electrode (CPE) utilizing cyclic voltammetry and amperometry analysis. Under the optimum condition, good linearity was observed between the quenched emission intensity of the system and MTX dosage in the range of 0.5–250 μM with a limit of detection (LOD) of 0.91 μM. The electrochemical method illustrated a much better response with an extensive linear range of 0.01–475 μM and a lower LOD (1.61 nM). Analytical recoveries and RSD% values were, respectively, in the range of 87.72%–110% and 0.33%–1.32% for the fluorometric system and 96%–106% and 0.77%–1.02% for the electrochemical platform. Finally, the selectivity of the sensor was evaluated against various common interfering species, and the results indicated satisfactory selectivity of the POMo dual‐mode system towards MTX. [ABSTRACT FROM AUTHOR]

Applications of macrocyclic compounds and their various metal complexes in biological fields have notably increased. Therefore, it is reasonable to synthesize novel macrocyclic compounds and assess their biological properties. In this research, several new Ni(II) complexes were prepared using hexamethyltetraaza macrocycles, and their biological activity was studied. Specifically, a fourteen-membered tetraaza macrocyclic diene ligand in its dihydroperchlorate form, Me6[14]diene⋅2HClO4 (L⋅2HClO4), along with its isomers tet-a and tet-b in their saturated 'ane' forms, were employed for complexation with Ni(II) acetate, followed by the addition of NaClO4. The process resulted in the formation of square planar [Ni[(L´)](ClO4)2 (L´ = L, tet-a, or tet-b) and octahedral [Ni(tet-b)(ClO4)2] complexes. Furthermore, axial addition reactions involving SCN–, Cl–, Br–, and I– with [Ni[(L´)](ClO4)2 led to the formation of six-coordinated octahedral complexes, including [Ni(L)(NCS)2], [Ni(tet-a)(NCS)2], [Ni(tet-b)(NCS)2] [Ni(tet-b)Cl2], [Ni(L)Br2], [Ni(tet-b)Br2] and [Ni(tet-b)I2]. Additionally, axial substitution reaction on the complex [Ni(tet-b)(ClO4)2] with SCN– produced a five-coordinated square pyramidal complex, [Ni(tet-b)(NCS)](ClO4). Modern analytical and spectroscopic techniques were used to characterize these complexes. It was observed that these complexes exhibited different geometries and electrolytic properties in different organic solvents where the Ni(II) showed different coordination modes. These complexes also displayed moderate antimicrobial activity against various bacteria. [ABSTRACT FROM AUTHOR]

This article reports the preparation of a novel functionalized magnetic nanoadsorbent through an addition reaction between Fe3O4 nanoparticles coated with allyl silica gel and 4-pyridinyl ethylene. A detailed characterization of Fe3O4@SiO2-yl-VP was conducted. Among them, in the infrared spectrum, we can easily see that the absorption peak of the C=C stretching vibration at 1660 cm−1 in the raw material disappears after the addition reaction, indicating the successful grafting of polymer on the surface of silica gel. The appearance of N element in the EDS spectrum also proves the successful completion of the addition reaction and the successful synthesis of Fe3O4@SiO2-yl-VP. At pH = 5 and pH = 7, it only takes half an hour for Fe3O4@SiO2-yl-VP to achieve maximum adsorption capacities of 85.06 and 73.78 mg/g for Hg (II) and Pb (II), respectively. The adsorption process conforms to the Langmuir model and the pseudo-first- and pseudo-second-order kinetic models and can be reused 11 times, demonstrating excellent reusability. [ABSTRACT FROM AUTHOR]

The rhodium‐catalyzed addition reaction of cyclo‐(PPh)5 to alkynes in refluxing THF efficiently provide 1,2,3‐triphospholenes, in which the –PPh–PPh–PPh– group is transferred from cyclo‐(PPh)5 by the cleavage of P−P bonds. In refluxing chlorobenzene, the reactions are accompanied by the formation of 1,2‐diphosphetes. When the triphospholenes containing P−P bonds are reacted with reactive alkynes under rhodium‐catalyzed conditions, unsymmetric phospholes are obtained. The rhodium‐catalyzed reactions can be used to synthesize various phosphorus‐containing heterocycles with different numbers of phosphorus atoms. [ABSTRACT FROM AUTHOR]

The C–F bond activation of perfluoronaphthalene by 5-SIDipp led to the formation of dicationic salts with two fluorides (3·2HF2) or heptafluorodiborate (3·2B2F7) as counter-anions. The anion exchange reaction of 3·2B2F7 with NBu4PF6 afforded a highly luminescent 3·2PF6. The in situ addition of cobaltocene in the reaction mixture of 5-SIDipp and perfluoronaphthalene led to a distinct Co(I) species. [ABSTRACT FROM AUTHOR]

Overcoming the significant volume strain in silicon‐based anodes has been the focus of research for decades. The strain/stress in silicon‐based anodes is inversely proportional to their size. In this study, we design atomic Si sites to achieve the ultimate size effect, which indeed exhibits a zero‐strain feature. Compared with conventional silicon‐based anodes with alloying addition reactions, the lithium‐ion storage mechanism of atomic Si sites is solid‐solution reactions, which brings about the zero‐strain feature. Additionally, the ligand structure of atomic Si sites remains constant during cycling. This zero‐strain feature results in excellent cycling stability. Furthermore, the exposed atomic Si sites enhance the electrochemical reaction kinetics, leading to outstanding rate performance. Moreover, the anode inherits the advantages of silicon‐based anodes, including a low working voltage (~0.21 V) and high specific capacity (~2300 mAh g−1 or ~1203 mAh cm−3). This work establishes a novel pathway for designing low/zero‐strain anodes. [ABSTRACT FROM AUTHOR]

Individuals suffering from voice disabilities have limited access to currently available automation technologies that operate through voice commands. To address this issue, an alternative voice recognition approach is essential without directly monitoring the audio signals generated from the vocal cord. In this work, the design of a chemically reactive and conductive sponge is reported to create an underwater vibration sensor with a fast response time and high sensitivity, through orthogonal modulation of conductivity (40–2150 kΩ), water repellence (0°–154°) and mechanical properties (0.32–2.63 MPa). This class of porous sponge sensors enables the identification of subtle water waves generated at the air–water interface and extends its utility to detecting a variety of locomotion (squatting, jumping, walking, etc.), as well as automated voice recognition using a deep learning model without direct contact with the human body. Overall, this underwater vibration sensor provides a novel basis for remote interaction with automated technologies, which finds use in medical diagnostics, human‐machine interfaces, and underwater communication systems. [ABSTRACT FROM AUTHOR]

Aiming at the problem of excessive swelling of conventional microspheres for oilfield use, a novel amphiphilic polymerizable crosslinker (AE) was synthesized by quaternary ammonium modification of an unstable crosslinker (AE) using acrylamide, 2-acrylamido-2-methylpropanesulfonic acid as the monomers, N,N′-methylene bisacrylamide as the stabilizing crosslinker, ammonium peroxysulfate and sodium bisulfite as the initiator, and water as the solvent by using a reversed microemulsion method. Double-networked nanomicrospheres were prepared. The preparation conditions of the microspheres were optimized by the surface response method, focusing on the effects of the initiator addition and reaction temperature, and total crosslinker addition on the formation of nanomicrospheres. The samples were characterized by FTIR, TGA, laser particle sizer, and SEM to evaluate the retarded expansion performance and the modulation drive performance. The results showed that the optimal conditions for the preparation of microspheres were m(oil phase):m(water phase) = 3:2, stirring speed of 550 r/min, total crosslinking agent dosage of 0.6% (based on the total mass of monomers, hereinafter the same), initiator dosage of 0.30%, reaction temperature of 45 °C, and reaction time of 4 h. Compared with the conventional polymer microsphere PAM, PAE was slow-expanded for 45 d at 60 °C, and the expansion multiplier was about 16 times, with slow-expansion characteristics; the blocking rate of PAE reached 98.3%, the oil repulsion rate was 73.11%, and the increase in the recovery rate could be up to 11.23%. In this paper, a new type of nanomicrosphere material is investigated to realize the efficient implementation of oil field conditioning and driving. [ABSTRACT FROM AUTHOR]

The first stereodivergent umpolung 1,5-conjugate addition reaction via synergistic Pd/Cu catalysts is reported. By dictating the absolute configuration of each chiral ligand ligated to corresponding metals, all four stereoisomers of the products are easily achieved. A series of amino acid moieties are introduced to the γ-position of the conjugated esters in high yields with excellent diastereoselectivities and enantioselectivities. The downstream transformations highlight the synthetic value of the method. [ABSTRACT FROM AUTHOR]

A flexible, shape-editable transparent wood (ATW) composite containing acetal linkages was prepared simultaneously through free radical polymerization and addition reaction between vinyl ether bonds and hydroxyl groups. In this system, the anisotropic hierarchical structure of wood acted as a reinforced skeleton, the flexible chain segment ensured flexibility at room temperature, and the dynamic acetal bonds were responsible for the shape memory and editability under relatively mild conditions, verifying the expanding applications of functionalized wood-based materials. [ABSTRACT FROM AUTHOR]

The anionic polyaddition of methyl‐substituted 1,1‐diphenylethylene derivatives, catalyzed by lithium diisopropylamide, was examined. Polymerization of the monomer was conducted at 50°C in THF with the addition of diisopropylamine. NMR and MALDI‐TOF‐MS analyses of the obtained polymer indicate that polymerization proceeded via a polyaddition reaction, in other words, repetition of the lithium amide‐induced metalation reaction of the monomer at the methyl group and the subsequent nucleophilic addition reaction of the corresponding benzyllithium with the vinyl group in the monomer. On the other hand, the unsubstituted diphenylethylene monomer could not be polymerized by the same reaction condition. Consequently, the resulting polymer was indeed obtained by an anionic polyaddition mechanism. In conclusion, a novel hydrocarbon polymer containing a phenyl group in the main chain of the repeating unit was successfully obtained from a methyl‐substituted 1,1‐diphenylethylene monomer. [ABSTRACT FROM AUTHOR]

The present study describes the synthesis of various bioactive compounds, including bis‐coumarins, bis‐lawsones, bis‐dimedones, and bis‐indolylmethanes, using a novel catalytic system called "Brønsted acid saponin combined catalyst" (BASapC). The BASapC was formed by combining p‐toluenesulfonic acid (PTSA) and saponin in an aqueous medium. The prepared BASapC proved to be effective in facilitating cascade‐type Knoevenagel–Michael addition reactions between various aromatic aldehydes with 4‐hydroxycoumarin, lawsone, dimedone, or indole at 80 °C. In the BASapC system, PTSA acted as a powerful Brønsted acid, activating reactants, whereas saponin served as a natural surfactant, enhancing the solubility of organic compounds in water. This catalytic approach established a straightforwardness and robustness of diversity‐oriented synthesis (DoS), delivering the desired products with good to excellent yields. Additionally, the BASapC exhibited recyclability for at least four cycles without significant loss of activity. [ABSTRACT FROM AUTHOR]

Since the review of Yorimitsu and Oshima in 2010, the past 15 years have witnessed significant progresses in the application of 1‐alkynylphosphorus compounds in organic synthesis. Owing to the reactive carbon‐carbon triple bond in association with the electron‐withdrawing phosphoryl group, they easily undergo transition metal‐catalyzed nucleophilic addition reactions at the β‐position with carbon‐ and heteroatom‐based nucleophiles to afford structurally diverse 1‐alkenyl phosphorus compounds. Especially, when 1‐alkynylphosphonates or phosphinates are used, intramolecular substitution reactions on P‐atom might occur in some cases, which would result in the formation of P‐based heterocycles. In addition, the existing triple bond makes them prone to go through addition reaction initiated cyclization reactions and [2+2], [2+3], [2+4], [2+5] and [2+2+2] cycloaddition reactions with other unsaturated bonds, which provides an efficient access to various P‐based heterocycles and phosphorylated carbon‐ and heterocycles. [ABSTRACT FROM AUTHOR]

Optically active molecule architectures stand as an important class of organic compounds and occupy a key role in academic and industrial communities. Particularly, the molecules bearing quaternary carbon are of vital importance because of its favorable conformation and valuable three‐dimensional molecules, which frequently play a key role in a broad spectrum of functional materials, pharmaceutical relevant natural molecules, and agrochemicals. Over the past few decades, a large number of synthetic strategies for the enantioselective construction of compounds with chiral quaternary carbon centers have been the focus of a number of research initiatives. In this review, the state‐of‐the‐art toward the synthesis of enantioenriched molecules bearing quaternary stereocenters are summarized, which could be segmented into four categories: 1) Construction of optically active quaternary carbon centers by addition to prochiral sp2 carbon; 2) Construction of optically active all‐carbon quaternary stereocenters via substitution at non‐chiral tetra‐substituted carbon; 3) Construction of optically active all‐carbon quaternary stereocenters via kinetic resolution; 4) Construction of optically active all‐carbon quaternary stereocenters via desymmetrization reactions. [ABSTRACT FROM AUTHOR]

Methyl-4-isothiazolin-3-one (MIT) is widely used in industrial production, but its persistence and potential biological toxicity in water environment have attracted widespread attention. Therefore, based on a Venturi tube cavitation reactor, a study was conducted on the process of oxidative degradation of methyl isothiazolinone using hydraulic cavitation technology combined with H2O2. With the aim of improving the degradation rate of MIT, the reaction time, inlet pressure, H2O2 addition amount, and MIT initial concentration were optimized. Through a series of experiments, the optimal reaction conditions were determined as follows: under the conditions of reaction time of 40 min, inlet pressure of 0. 5 MPa, H2O2 addition amount of 5 mL/L, and MIT initial concentration of 15mg/L, the degradation rate of MIT reached 69%. In order to gain a deeper understanding of the degradation mechanism of MIT, Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) technology was used to analyze the intermediate products of MIT degradation, and to speculate on the degradation process of MIT under this process condition. MIT mainly degrades its five membered ring structure through oxidation and addition reactions. This indicates that under the current experimental conditions, the degradation rate of MIT has reached a stable level, and further improving the degradation efficiency may require adjusting other parameters. On this basis, the initial rate method was used to determine that the degradation reaction of MIT under this process condition is a zero order reaction, that is, the reaction rate is not related to the concentration of MIT, but is influenced by other factors. Using the Coast Redfern model, the apparent activation energy of MIT was estimated to be 31. 127 kJ/mol, providing an important basis for further optimizing the degradation process. [ABSTRACT FROM AUTHOR]

Different spectroscopic techniques and Density Functional Theory (DFT)/Time-Dependent Density Functional Theory (TDDFT) calculations have been employed to investigate the dual channel CN− detection behaviour of the developed chemo-dosimeter (AK3). The CN− with AK3 reaction triggered a colour change from pale yellow to colourless and enhanced fluorescence. UV–Vis, fluorescence, 1H & 13C NMR and mass techniques coupled with theoretical calculations (Mulliken charges, dihedral angles) revealed that the CN− sensing process mechanism involves deprotonation of the N–H group followed by nucleophilic addition reaction. Detailed TD-DFT calculations showed that the relaxation of excited electrons from LUMO and to two different ground states is responsible for the weak/moderate fluorescence of AK3. Nucleophilic addition of CN− to the C-atom of the CH = CH bridge terminated the π-conjugation between donor and acceptor regions, reduced the coplanarity, decreased the ICT transition and consequently enhanced the fluorescence of the probe. The practical utility of the probe was demonstrated by detecting cyanide in food materials and determining CN− in environmental water samples. [ABSTRACT FROM AUTHOR]

As a significant variant of the Michael reaction, the 1,6‐addition reaction has undergone considerable development over the past decade. This effective strategy enables the synthesis of a variety of novel and potentially bioactive functional molecules. In this review, we summarize the recent progress in NHC‐catalyzed 1,6‐addition reactions, highlighting their efficiency in the rapid synthesis of complex functional molecules. We also provide our perspectives on the future development of this dynamic and highly active research area. [ABSTRACT FROM AUTHOR]

A thorough understanding of the lignin–carbohydrate complex (LCC) structure has a significant meaning in the high-value utilization of lignocellulose. In this work, the complex (DHPKGC) was obtained by an addition reaction between konjac glucomannan (KGM) and quinone methides generated in the synthesis of dehydrogenation polymers (DHPs) to simulate the formation of LCCs. The effect of pH on the prepared DHPKGC was investigated. The structure of the DHPKGC was characterized by Fourier Transform Infrared (FTIR), 13C-Nuclear Magnetic Resonance (13C-NMR), and two-dimensional Heteronuclear Single Quantum Coherence Nuclear Magnetic Resonance (2D HSQC NMR) analyses. The results indicated the pH of 4.0 was conducive to the polymerization reaction between DHPs and oxidized KGM by the TEMPO/NaClO/NaBr system. In addition, the resultant DHPKGC was connected by benzyl ester linkages. Overall, this study aims to gain greater insight into the process of LCC formation in plants. [ABSTRACT FROM AUTHOR]

• The quantum chemical calculations and ab initio dynamics simulation were adopted to clarify the gas phase and air-water interface reaction mechanisms of CH 3 CHOO and H 2 SO 4. • The reaction of CH 3 CHOO with H 2 SO 4 plays an active role in the CH 3 CHOO removal channel. • The formed interfacial CH 3 HC(OOH)OSO 3 − and H 3 O+ ions can attract candidate species for particle formation. • The oligomerization reaction of CH 3 CHOO with HPES in the gas phase is both thermochemically and kinetically favored • The reaction product can form stable clusters with sulfuric acids, ammonias and water molecules. The formation of oligomeric hydrogen peroxide triggered by Criegee intermediate maybe contributes significantly to the formation and growth of secondary organic aerosol (SOA). However, to date, the reactivity of C2 Criegee intermediates (CH 3 CHOO) in areas contaminated with acidic gas remains poorly understood. Herein, high-level quantum chemical calculations and Born-Oppenheimer molecular dynamics (BOMD) simulations are used to explore the reaction of CH 3 CHOO and H 2 SO 4 both in the gas phase and at the air-water interface. In the gas phase, the addition reaction of CH 3 CHOO with H 2 SO 4 to generate CH 3 HC(OOH)OSO 3 H (HPES) is near-barrierless, regardless of the presence of water molecules. BOMD simulations show that the reaction at the air-water interface is even faster than that in the gas phase. Further calculations reveal that the HPES has a tendency to aggregate with sulfuric acids, ammonias, and water molecules to form stable clusters, meanwhile the oligomerization reaction of CH 3 CHOO with HPES in the gas phase is both thermochemically and kinetically favored. Also, it is noted that the interfacial HPES− ion can attract H 2 SO 4 , NH 3 , (COOH) 2 and HNO 3 for particle formation from the gas phase to the water surface. Thus, the results of this work not only elucidate the high atmospheric reactivity of C2 Criegee intermediates in polluted regions, but also deepen our understanding of the formation process of atmospheric SOA induced by Criegee intermediates. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, a novel bio-based polyphenol diol intermediate (VDP) was synthesized through a combination of aldimine condensation and addition reactions, utilizing vanillin, 4,4′diamino diphenylmethane (DDM), and 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide (DOPO) as reactants, then various contents of VDP was introduced covalently into the polyurethane backbone. The integration of VDP has notably improved the flame retardancy of polyurethane elastomer, the limiting oxygen index (LOI) of the elastomer was elevated from 23% to 30%, and reaches V-0 rating in the UL-94 vertical burning test. The enhancement of flame retardancy is attributed to the introduction of VDP units, which not only generate PO· and PO 2 ∙ that can capture active free radicals during combustion, but also releases non-flammable gases to improve the flame-retardant effect. Moreover, the VDP enhances the decomposition activation energy values (E α) from 109.3 to 227.6 KJ/mol at mass loss rate (α) = 10%, which is attributed to the rigid benzene ring structure of VDP that significantly enhances the intermolecular interactions within the polyurethane chains. Furthermore, the elastomer shows excellent rebound resilience and reprocessability, retaining 98.6% of its original mechanical properties after multiple cycles of hot-press remolding and solvent casting. [ABSTRACT FROM AUTHOR]

(E)-6-Methoxy-1-methyl-3-(2-(3-methyl-4-nitroisoxazol-5-yl)vinyl)quinolin-2(1H)-one dye (MQI) has been synthesized, and its structural and electronic properties have been characterized by employing UV-vis spectroscopy in combination with computational methods. The MQI dye has been assessed as an activated Michael acceptor-type probe toward bisulfite ions. This reaction was kinetically tested in different mild, cationic (cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, and cetylpyridinium bromide), and zwitterionic (N-decyl-N,N-dimethyl-3-ammonio-1-propanesulfonate, N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate, and N-hexacyl-N,N-dimethyl-3-ammonio-1-propanesulfonate) micellar solutions at pH ∼ 5.5. Both micellar media remarkably allow the addition reactions, increasing the reactivity of MQI towards bisulfite ions, the biggest effects were found in the presence of cationic micelles. The binding constants of MQI with the micelles and the rate constants were determined from kinetic data, which were interpreted on the basis of the pseudophase kinetic model. The kinetic study and the product analysis allow us to highlight the relevant role of the association between MQI dye and the micellized surfactant, allowing efficient nucleophilic addition of bisulfite ions. The findings of this work will be valuable for the use of micellar solutions as an alternative medium to replace the use of toxic solvents to carry out organic reactions to perform nucleophilic addition reactions of bisulfite. [ABSTRACT FROM AUTHOR]

An atom‐economical sequential‐flow synthesis of donepezil, a widely prescribed drug for Alzheimer's disease, was accomplished using inexpensive, commercially available precursors. This achievement was made possible by reconfiguring the synthetic route to include only heterogeneous catalytic addition and condensation reactions, with a particular emphasis on skeletal transformation and bond formation through hydrogenation processes. Notably, water was the sole byproduct in this synthesis. A crucial aspect of this work was the development of appropriate continuous‐flow processes to achieve a one‐flow synthesis. This was accomplished by implementing in‐line treatments of the main reaction stream to eliminate inhibitory factors that could affect catalyst performance in the hydrogenation steps. [ABSTRACT FROM AUTHOR]

The reaction of unsubstituted α-nitrocinnamic nitrile with 1-methylpyrrole ends with the formation of an AdN product, whereas the reactions of 2-aryl-2-nitroacrylonitriles with such N,N- and N,S-binucleophiles as hydrazine, phenylhydrazine, and o-aminothiophenol lead to transformation products of the initially formed adducts, linear azines and phenylhydrazones, or to a heterocyclic benzothiazole structure. [ABSTRACT FROM AUTHOR]

Synthesis of functionalized 1,3‐indandiones containing‐cyclopentenones and ‐benzotropones has been achieved by the reaction of 1,5‐diphenylpenta‐1,4‐diyn‐3‐ones with 1,3‐indandiones, bindone respectively. The developed method involves Michael‐anti‐Michael addition cascade reactions under transition‐metal‐free conditions. This is the first report to synthesise diverse benzotropone fused with 1,3‐indandiones under transition metal‐free conditions from bindone. [ABSTRACT FROM AUTHOR]

Developing effective latent curing agent for rapid curing of epoxy resins at low temperatures remains challenging. This study reports a latent curing agent, ortho‐cresol phenolic epoxy resin‐bisphenol A (EOCN‐BPA), prepared through the addition reaction of o‐methyl phenolic epoxy resin with BPA. When blended with dicyandiamide (DICY) in a 1:3 molar ratio, EOCN‐BPA/DICY is used to cure a linear epoxy phenolic novolac (EPN) resin (epoxy equivalent: 550 g eq−1, softening point: approximately 82°C), at an onset curing temperature of 90°C, which is considerably lower than the onset curing temperature of DICY with EPN (160°C). However, EOCN‐BPA does not react with EPN without a catalyst. Therefore, this latent curing system is successfully applied in powder coatings, rapid curing at 120°C within 3 min without an additional catalyst, outperforming the EPN/EOCN‐BPA system using cocatalyst 2‐methylimidazole. Consequently, DICY catalyzes the curing reaction between the phenol hydroxyl group and epoxy resin and participates in it. The prepared powder coating exhibits excellent storage stability, maintaining its properties for over 3 months at room temperature. These findings demonstrate the excellent latent properties of EOCN‐BPA/DICY, highlighting its potential as a highly effective latent curing agent. [ABSTRACT FROM AUTHOR]

Chiral tertiary alcohols are an important structural motif, however, the general and efficient methodologies for their synthesis are less reported. Herein, we report a Ni(ІІ)-catalyzed asymmetric alkenylation and arylation of aryl ketones with organoborons under air via a 1,5-metalate shift strategy to obtain chiral tertiary allylic alcohols and diaryl alcohols. The reaction demonstrates good functional group tolerance and delivers chiral tertiary alcohols with good to excellent results. Furthermore, this method can be applied to the late-stage modification of drugs and the efficient synthesis of natural products. Notably, the reaction proceeds through an outer-sphere mechanism. The Ni(II) complex functions both as a Lewis acid to activate the ketone and create a chiral environment, and as coordination bridge linking the ketone and the organoboron-derived "ate" complex, facilitating the 1,5-metalate shift without forming a C-Ni bond. This approach contrasts with traditional transition metal-catalyzed nucleophilic addition reactions that involve carbon-metal bond formation. Chiral tertiary alcohols are an important structural motif, but the general methodologies for the synthesis are less reported. Herein, the authors report a Ni(ІІ)-catalyzed asymmetric alkenylation and arylation of aryl ketones with organoborons under air via a 1,5-metalate shift to obtain chiral tertiary allylic alcohols and diaryl alcohols. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) calculation has been used to reveal palladium‐catalyzed mode of diaziridinone ring activation. Our theoretical studies found that oxidative addition of di‐tert‐butyldiaziridinone to Pd(II) can give a high valent Pd(IV) intermediate, along with the cleavage of N─N bond in di‐tert‐butyldiaziridinone through a concerted three‐membered‐cyclic transition state. Subsequent transformations via reductive elimination and β‐N elimination give the desired indolo[3,2‐b]indole product. The competitive activation modes such as metathesis and migratory insertion can be excluded in our selected model reaction. The rate‐determining step of this reaction is the oxidative addition of di‐tert‐butyldiaziridinone step. Distortion‐interaction analysis was conducted to reveal that the oxidative addition mode of di‐tert‐butyldiaziridinone is superior to the metathesis mode due to the lower interaction energy. [ABSTRACT FROM AUTHOR]

This study introduces a novel photoelectrochemical (PEC) sensor for the highly selective detection of sulfur dioxide (SO2) using an organic photoactive molecule probe (OPM). OPM is synthesized through a one‐step coupling reaction, featuring a typical photosensitizer D‐π‐A structure. By covalently bonding OPM with a TiO2 substrate, a PEC sensor is constructed, exhibiting a significant photocurrent response under visible light excitation. The specific addition reaction between SO2 and OPM disrupts its conjugated structure, reducing the photocurrent response and achieving highly selective detection of SO2. The sensor demonstrates excellent performance in real water samples, emphasizing its practical applications. [ABSTRACT FROM AUTHOR]

Objective: The study commenced with the conversion of 4-(1H-indol-3-yl)butanoic acid (I) into ethyl 4-(1H-indol-3-yl)butanoate (II), succeeded by the synthesis of the hydrazide nucleophile, 4-(1H-indol-3-yl)butanohydrazide (III). Methods: Following this, nucleophilic addition reactions of (III) with various electrophilic aldehydes (IVa–IVg) were conducted to yield the targeted derivatives (Va–Vg/Vʹa–Vʹg). The structural elucidation of all synthesized compounds relied on IR, 1H, 13C NMR, HMBC, and CHN analysis. Results and Discussion: Evaluation of the inhibitory effects of these heterocyclic butanohydrazides (Va–Vg/Vʹa–Vʹg) against the α-glucosidase enzyme revealed significant inhibition by compounds (Vg/Vʹg) compared to the standard. Conclusions: Hemolytic analysis indicated mild cytotoxicity towards red blood cell membranes, indicating the potential of these molecules as nontoxic medicinal scaffolds for skin pigmentation and related disorders. [ABSTRACT FROM AUTHOR]