Conversion Of Functional Groups Research Articles

Efficient and Stable p-i-n Perovskite Solar Cells Enabled by In Situ Functional Group Conversion.

Chemical additives play a critical role in the crystallization kinetics and film morphology of perovskite solar cells (pero-SCs), thus affecting the device performance and stability. Especially, carboxylic acids and their congeners with a -COOH group can effectively serve as ligands to fortify the structural integrity and mitigate the risk of lead efflux. However, direct addition of -COOH into the precursor solution could retard the crystallization kinetics of the perovskite during film formation due to the strong coordination. Here, we present a novel approach of in situ functional group conversion using Bis(2,5-dioxopyrrolidin-1-yl) 4,7,10,13-tetraoxahexadecanedioate (Bis-PEG4-NHS ester) as an additive in the antisolvent, which underwent a functional group transformation from -COOR to -COOH during the annealing process through a hydrolysis reaction of Bis-PEG4-NHS ester. The corresponding hydrolysates exhibit enhanced interactions with PbI2 and FAI, contributing to the structural integrity and the defect passivation. Our findings offer valuable insights into the chemical interactions within the crystal growth process, achieving the p-i-n pero-SC device with an efficiency of 25.79% (certified as 25.47%) and notable long-term stability.

Iron‐Catalyzed Regioselective Borobenzylation of Vinyl Arenes

AbstractHerein, catalytic difunctionalization of vinyl arenes is reported using an iron salt as a catalyst without ligands. A series of substituted alkylboronic acid esters was obtained as a single regioisomer from vinyl arenes at 50 °C. This multicomponent protocol enabled the formation of C−C and C−B bonds to produce boroalkylated products in a single process. A non‐radical pathway is proposed for the reaction in contrast to the radical pathways of iron‐catalyzed hydroalkylation reactions. The organoboron compounds generated from this reaction were further utilized for diverse functional group conversions.

Recent Advances in Diazophosphonate Chemistry: Reactions and Transformations

AbstractDiazophosphonates function as indispensable synthetic intermediates within the domain of organic chemistry, serving as precursors for a diverse range of molecules, with potential applications as bioactive compounds. α-Diazomethylphosphonates showcase expansive reactivity and elevated levels of enantioselectivity in asymmetric transformations, especially in conjunction with suitable catalyst systems. This review compiles the latest advancements in diazophosphonate chemistry from 2016 to 2024, highlighting their reactivity and transformative potential in organic synthesis. Diazophosphonates, regarded as revolutionary compounds, exhibit unique attributes as carbene precursors, driving diverse chemical reactions such as [3+2] cycloaddition, asymmetric [3+2] cycloaddition, asymmetric [3+3] cycloaddition, and asymmetric substitution reactions. Their adaptability in functional group conversions underscores their pivotal role in various synthetic methodologies. The review highlights the growing interest in diazophosphonate reactions among synthetic chemists, fostering novel synthetic strategies and expanding their application horizons. The multifaceted utility of diazophosphonates as reagents, synthetic intermediates, precursors, and catalysts underscores their significance in modern organic chemistry and pharmaceutical applications, prompting further exploration into this dynamic field.1 Introduction2 [3+2] Cycloaddition Reactions3 Asymmetric [3+2] Cycloaddition Reactions4 Asymmetric [3+3] Cycloaddition Reactions5 Asymmetric Substitution Reactions6 Diazophosphonates as Carbene Precursors7 Diazophosphonates in the Chemistry of Fluorinated Compounds8 Other Reactions9 Future Directions10 Conclusion

Kinetic of Light Transmission during Setting and Aging of Modern Flowable Bulk-Fill Composites.

The current development of dental materials aims to improve their properties and expand their clinical application. New flowable bulk-fill composites have been released which, unlike what was previously common in this material category, are intended to be used alone and without a top layer, in various cavities. The study compares their kinetic of light transmission during monomer-to-polymer conversion on a laboratory-grade spectrometer, as well as their elastoplastic and aging behavior under simulated clinical conditions. Major differences in the kinetic of light transmission was observed, which is related to the degree of mismatch between the refractive indices of filler and polymer matrix during polymerization and/or the type of initiator used. Compared to the literature data, the kinetic of light transmission do not always correlate with the kinetic of functional group conversion, and therefore should not be used to assess polymerization quality or to determine an appropriate exposure time. Furthermore, the initial mechanical properties are directly related to the volumetric amount of filler, but degradation during aging must be considered as a multifactorial event.

One-Step Synthesis of [18F]Aromatic Electrophile Prosthetic Groups via Organic Photoredox Catalysis.

To avoid the harsh conditions that are oftentimes adopted in direct radiofluorination reactions, conjugation of bioactive ligands with 18F-labeled prosthetic groups has become an important strategy to construct novel PET agents under mild conditions when the ligands are structurally sensitive. Prosthetic groups with [18F]fluoroarene motifs are especially appealing because of their stability in physiological environments. However, their preparation can be intricate, often requiring multistep radiosynthesis with functional group conversions to prevent the decomposition of unprotected reactive prosthetic groups during the harsh radiofluorination. Here, we report a general and simple method to generate a variety of highly reactive 18F-labeled electrophiles via one-step organophotoredox-mediated radiofluorination. The method benefits from high step-economy, reaction efficiency, functional group tolerance, and easily accessible precursors. The obtained prosthetic groups have been successfully applied in PET agent construction and subsequent imaging studies, thereby demonstrating the feasibility of this synthetic method in promoting imaging and biomedical research.

Towards post-curing parameters optimization of phthalonitrile composites through the synergy of experiment and machine learning

Phthalonitrile composites are highly anticipated in fields such as aerospace, marine, and electronics due to their exceptional heat resistance, excellent high-temperature mechanical properties, and outstanding processability. The conversion of nitrile functional groups to macrocyclic structures during post-curing is essential for performance enhancement. However, the influence of post-curing conditions on the mechanical properties of phthalonitrile composites is complicated, and the underlying mechanism remains unclear. In this study, an experimental and machine learning synergic strategy was employed to optimize the post-curing parameters of the phthalonitrile composites, including temperature, time, and pressure. Through mechanical experiments conducted at both room temperature and 400 °C, scanning electron microscope, and dynamic mechanical analysis, the underlying mechanism of the influence of post-curing parameters on the composite mechanical properties was revealed. The enhancement of the polymerization degree brought about by post-curing is the decisive factor for high-temperature performance, while the room-temperature properties are a tradeoff between the polymerization degree improvement and the defect proliferation. The genetic algorithm-optimized backpropagation (GA-BP) neural network was trained for the efficient and accurate prediction of the optimal post-curing parameters. The tendency of mechanical properties with the post-curing parameters predicted by machine learning is consistent with the mechanism revealed by experiments.

Optimization of Transesterification Process for Biodiesel Production using Jatropha Oil

Biodiesel has attracted considerable attention during the past decade as a renewable, biodegradable, and nontoxic fuel alternative to fossil fuels. Biodiesel can be obtained from vegetable oils (both edible and non-edible) and from animal fat. Biodiesel was produced through esterification of Jatropha oil using an alkaline catalyst. The process was carried out at the reaction temperatures of 63 and 55°C, with a 6:1-11:1 oil to methanol molar ratio, and the concentration was verified. In this research work, a yield of 91.78% and 80% was achieved. Furthermore, the flash point of 129.1°C obtained indicates that the biodiesel is within the specification of ASTM. Jatropha curcas Linnaeus, a multipurpose plant, contains a high amount of oil in its seeds which can be converted to biodiesel. J. curcas is probably the most highly promoted oilseed crop at present in the world. The availability and sustainability of sufficient supplies of less expensive feedstock in the form of vegetable oils, particularly J. curcas, and efficient processing technology to biodiesel will be crucial determinants of delivering competitive biodiesel. Oil contents, physicochemical properties, and fatty acid composition of J. curcas are reported in research. The fuel properties of Jatropha biodiesel are comparable to those of fossil diesel and conform to the ASTM standard. The objective of this review is to give an update on the J. curcas L. plant, the production of biodiesel from the seed oil, and research attempts to improve the technology of converting vegetable oil to biodiesel and the fuel properties of Jatropha biodiesel. There is also a need to carry out a lifecycle assessment and assess the environmental impacts of introducing large-scale plantations. Furthermore, there is still a dearth of research about the influence of various cultivation-related factors and their interactions and influence on seed yield. The formation of biodiesel was confirmed by FT-IR and GC-MS analysis, and the conversion of ester functional group into methyl esters was verified, and characteristic properties of biodiesel were successfully determined. Keywords: Biodiesel, Jatropha oil, transesterification, catalyst, optimization, renewable energy and sustainability

A Facile and Green Approach for the Preparation of Amine-Functionalized Poly(ethylene glycol) by Reducing Poly(ethylene glycol) Azide with Dithiothreitol.

A facile and green approach for the preparation of PEGn-NH2s from PEGn-N3s in water with DTT as the reduction reagent has been developed, avoiding the introduction of metal ions and difficulties in purification compared to the traditional synthesis process of PEGn-NH2s. A series of high-purity linear and multiarm PEGn-NH2s with different molecular weights were synthesized, demonstrating the versatility of this method. Additionally, HS-PEG45-NH2 with high fidelity of thiol and amine was easily prepared through the one-step two functional group conversion of N3-PEG45-S-S-PEG45-N3, and the PEG-based NH2-PEG@AuNPs were also prepared. This technology will promote the application of PEGn-NH2s in the fields of medicine and biomaterials.

DL‐malic acid for inhibiting the re‐ignition of long‐flame coal and its micro‐reaction mechanism

AbstractTo study the metal ion chelating agent (DL‐malic acid) inhibiting oxidation characteristics of residual coal in goaf, the microscopic thermal transformation characteristics of the treated coal samples were obtained using apparent morphology, infrared spectroscopy, free radical testing, and thermal analysis. The results demonstrate that after the addition of malic acid, the sphericity and roundness of the coal samples decrease, and the small fractured particles accumulate in the pores of the oxidized coal samples and, thereby, reduce the number of coal–oxygen contact sites. The addition of 10% malic acid promotes the conversion of functional groups (FG) and free radicals in pre‐oxidized coal, inhibits the catalytic effect of metal ions, generates more active sites, and increases the total heat release during the combustion process. There are strong endothermic points in the malic acid‐treated coal samples, and the free water evaporation blocked by small particles in the holes delays the initial heat release temperature of the coal samples. Pre‐oxidation can promote changes in the valence state of metal ions in coal, increase the adhesion between broken pre‐oxidized coal particles via malic acid chelation, and lose the catalytic effect of metal ions; this inhibits the process of oxidative re‐ignition of coal samples.

Electrochemical selenylative ipso-annulation of N-benzylacrylamides to construct seleno-azaspiro[4.5]decadienones.

Herein, we present the electrochemical synthesis of selenylated azaspiro[4.5]decadienones through domino selenylation/ipso-annulation of N-benzylacrylamides with diselenides. The method showed a wide substrate scope under mild and external oxidant-free reaction conditions, involving the construction of C-Se and C-C bonds. Gram-scale synthesis and further functional group conversion of the product are also demonstrated.

Synthesis of pyrenocycloalkenes by using [2 + 2] photocycloaddition to pyrene and Diels–Alder reaction

Photoreaction of pyrene 1 with methyl cinnamate 15a gave a photocycloadduct 16a at 4,5-position of pyrene stereoselectively. Oxidation of 16a using DDQ yielded a pyrenocyclobutene derivative 18a. Functional group conversion of the ester moiety of 18a resulted in the synthesis of carboxylic acid 19, alcohols 20 and 21, sulfonate 23, and methylenecyclobutene 24. Diels–Alder reactions of 18a with electron-deficient alkenes or alkynes 25a–f afforded cycloadducts, pyrenocyclohexenes 26a–c and pyrenocyclohexadienes 26e, f stereoselectively in good yields. Thermal reactions of pyrenocyclobutene-linked electron-deficient alkenes 22a, b produced 4-benzyl-5-alkenylpyrenes 29a, b via ring cleavage followed by 1,5-hydrogen transfer.

Concise Synthesis of (±)-Fortuneicyclidins and (±)-Cephalotine B Enabled by Pd-Catalyzed Dearomative Spirocyclization.

Total syntheses of C11-oxygenated Cephalotaxus alkaloids, fortuneicyclidins A and B, and cephalotine B, were achieved. The key for the synthesis is a Pd-catalyzed dearomative spirocyclization of bromofurans with N-tosylhydrazones, followed by acid-mediated tandem transformation to construct the tetracyclic skeleton with the C11-oxygen functional group. Chemo-selective and catalytic functional group conversions of the tetracyclic intermediate completed the synthesis of fortuneicyclidins and cephalotine B in 8 and 9 steps, respectively.

Functional Group-Dependent Proton Conductivity of Phosphoric Acid-Doped Ion-Pair Coordinated Polymer Electrolytes: A Molecular Dynamics Study.

Toward deployment of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) in our daily lives, multiple research efforts have been dedicated to develop high-performance phosphate-doped polymer electrolytes. Recently, ion-pair coordinated polymers have garnered attention for their high stability and proton conductivity. However, a comprehensive understanding of how proton transport properties are modified by the functional groups present in these polymers is still lacking. In this study, we employ molecular dynamics (MD) simulations to investigate the impact of different functional group types and conversion ratios on conductivity. We find that Grotthuss-type hopping transport predominantly governs the overall conductivity, surpassing vehicular transport by factors of 100-1000. As conductivity scales with proton concentration, we observe that less-bulky functional groups offer advantages by minimizing the volume expansion associated with increased conversion ratios. Additionally, we show that a strong ion-pair interaction between the cationic functional group and the phosphate anion disrupts the suitable intermolecular orientations required for efficient proton hopping between phosphate and phosphoric acid molecules, thereby diminishing the proton conductivity. Our study underscores the importance of optimizing the strength of ion-pair interactions to balance stability and proton conductivity, thus paving the way for the development of ion-pair coordinated polymer electrolytes with improved performance.

Methyl Ketones as Alkyl Halide Surrogates: A Deacylative Halogenation Approach for Strategic Functional Group Conversions.

Alkyl halides are versatile precursors to access diverse functional groups (FGs). Due to their lability, the development of surrogates for alkyl halides is strategically important for complex molecule synthesis. Given the stability and ease of derivatization inherent in common alkyl ketones, here we report a deacylative halogenation approach to convert various methyl ketones to the corresponding alkyl chlorides, bromides, and iodides. The reaction is driven by forming an aromatic byproduct, i.e., 1,2,4-triazole, in which N'-methylpicolinohydrazonamide (MPHA) is employed to form a prearomatic intermediate and halogen atom-transfer (XAT) reagents are used to quench the alkyl radical intermediate. The reaction is efficient in yielding primary and secondary alkyl halides from a wide range of methyl ketones with broad FG tolerance. It also works for complex natural-product-derived and fluoro-containing substrates. In addition, one-pot conversions of methyl ketones to various other FGs and annulations with alkenes and alkynes through deacylative halogenation are realized. Moreover, an unusual iterative homologation of alkyl iodides is also demonstrated. Finally, mechanistic studies reveal an intriguing double XAT process for the deacylative iodination reaction, which could have implications beyond this work.

Study on the Coal-Oxygen Intrinsic Reaction at Low Temperature by the Subtraction Method.

Coal oxidation involves complex physical and chemical processes as well as many reaction pathways. The subtraction method was used to investigate the law of the coal-oxygen intrinsic reaction at low temperatures. The subtraction method is to subtract the characteristic curve of the coal reaction in N2 from the characteristic curve of coal oxidation in air, which can remove the influence of pyrolysis reaction, water evaporation, and gas desorption on coal low-temperature oxidation, and ultimately obtain the coal-oxygen intrinsic reaction curve under the pure oxidation pathway. To reveal the internal relationship of the coal-oxygen intrinsic reaction between the release of gas products and the conversion of active functional groups, a temperature-programmed system was used to analyze the law of index gas products. Furthermore, Fourier infrared spectroscopy was used to analyze the conversion of active functional groups in the low-temperature reaction process of coal. The findings revealed that the coal-oxygen intrinsic reaction obtained through subtraction played a significant role in the release of gas and the conversion of aliphatic hydrocarbons in the overall process of the coal low-temperature reaction. However, the alterations in the N2 atmosphere were relatively weak. The gas release of CO and CO2 gradually increased with increasing temperature, as did the concentration of oxygen-containing functional groups, and there was a positive correlation between them.

VOC Bonding of Heterointerface Boosting Kinetics of Free‐Standing Na5V12O32 Cathode for Ultralong Lifespan Sodium‐Ion Batteries

AbstractThe flexible free‐standing cathodes with high energy density have been challenging toward wearable sodium‐ion batteries (SIBs). Herein, Na5V12O32 nanobelts (NVO‐NBs)‐based heterostructure is fabricated with boosting the sodium‐ion kinetic characteristics to address the challenges. In the heterostructure, the controllable VOC bonds are generated at the interface originating from the chemical conversion of functional groups of the reduced graphene oxides (rGOs) with VO bonding of NVO through interfacial electronic interactions. The interfacial synergistic between the brilliant bonding properties and the inherent formation of a stress field at the heterointerface motivated by work function difference can reduce the Na+ diffusion barrier, facilitate charge transfer, hence accelerates reaction kinetics and electron/ion transport, as well as modifying the electronic structure to realize a cherished adsorption energy of Na+. Therefore, the optimized NVO‐NBs‐based heterostructure exhibits exceptional rate capability (213 mAh g−1 at 0.2 C with 100 mAh g−1 at 10 C) and ultralong cycling stability (95.4%, 3000 cycles at 5 C). This work demonstrates that the controllable heterostructure interface with abundant chemical bonds is an effective approach to exploit potential cathodes for rechargeable batteries.

Carbon Catalyst Support Modification by Nitrogen Via Nitric Oxide Treatment

In the present work the method of carbon material Sibunit modification by the NO treatment under static reactor condition is proposed. It is shown that the composition and amount of nitrogen- and oxygen-contained functional groups is determined by the treatment conditions (temperature, duration), which allows controlling the result of the modification. The process of Sibunit modification by NO is studied by XPS and N2 adsorption. The mechanism of Sibunit modification as the carbon layers etching by NO through the conversion of oxygen-contained functional groups into NOx-groups (–NO and –NO2) and further into pyridic and pyrrolic nitrogen-contained groups is assumed. Developed procedure of nitrogen introduction into carbon material is simple for realization, that is important for practical applications.

One-pot ternary sequential reactions for photopatterned gradient multimaterials

One-pot ternary sequential reactions for photopatterned gradient multimaterials

Upconversion particle-assisted NIR polymerization enables microdomain gradient photopolymerization at inter-particulate length scale

High crosslinking and low shrinkage stress are difficult to reconcile in the preparation of performance-enhancing photopolymer materials. Here we report the unique mechanism of upconversion particles-assisted NIR polymerization (UCAP) in reducing shrinkage stress and enhancing mechanical properties of cured materials. The excited upconversion particle emit UV-vis light with gradient intensity to the surroundings, forming a domain-limited gradient photopolymerization centered on the particle, and the photopolymer grows within this domain. The curing system remains fluid until the percolated photopolymer network is formed and starts gelation at high functional group conversion, with most of the shrinkage stresses generated by the crosslinking reaction having been released prior to gelation. Longer exposures after gelation contribute to a homogeneous solidification of cured material, and polymer materials cured by UCAP exhibit high gel point conversion, low shrinkage stress and strong mechanical properties than those cured by conventional UV polymerization techniques.

Substituted meta[n]Cycloparaphenylenes: Synthesis, Photophysical Properties and Host-Guest Chemistry.

Breaking the centrosymmetry of [n]cycloparaphenylenes ([n]CPPs) by one meta connection, leads to bright emission in the typically non-fluorescent smaller derivatives, conserving their size dependent emissive properties. Using the building block strategy for [n]CPPs, different nitrile substituted meta[n]CPPs (n = 6, 8, 10) have been prepared. The nitrile substituent offers a convenient handle for functional group conversions (e.g., carboxylic acid, amide, aldehyde, as well as 1H-tetrazole). Besides the synthetic work, the photophysical properties of these novel m[n]CPP derivatives have been characterized. Additionally, the host-guest ability of cyano-m[10]CPP has been explored by studying its complexation with fullerene C60. These insights open new applications of meta[n]CPPs as fluorophore in synthetic organic chemistry, material sciences as well as biomedical research.