Cobalt(III) Complexes as Bifunctional Hydrogen‐Bond Donor Catalysts Featuring Halide Anions for Cyclic Carbonate Synthesis at Ambient Temperature and Pressure: A Mechanistic Insight

Asian Journal of Organic Chemistry, Год журнала: 2022, Номер 11(5)

Опубликована: Фев. 24, 2022

Abstract The metal‐templated hydrogen bond donors (HBD) are prospective catalytic systems for the activation of organic molecules in chemical reactions. Here we report application chiral cationic Co(III) complexes based on commercially available ( S , )‐1,2‐diaminocyclohexane and R )‐1,2‐diphenylethylendiamine salicylaldehydes with an iodide counter‐anion as bifunctional one‐component donor/nucleophilic catalysts conversion carbon dioxide epoxides into valuable cyclic carbonates under solvent‐ co‐catalyst free conditions. We demonstrated that complex Λ( )‐ 2 is superior to Δ( 1 a catalyzing reaction at ambient conditions (RT bar CO ). TON TOF values 850 35 h −1 respectively, were achieved low catalyst loading (0.1 mol %) 10 bars 100 °C. Furthermore, catalyzed diluted air/CO mixture (15 vol % ) producing desired styrene carbonate up 75% yield. A plausible cycle consistent all experimental observations was proposed DFT calculations. calculations elucidated difference ring opening step cases propylene oxide oxide. In addition, kinetic resolution terminal observed selectivity factor s 1.6 case .

Язык: Английский

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Synthesis of Cyclic Carbonates Catalyzed by CaI₂–Et₃N and Studies on Their Biocatalytic Kinetic Resolution

ACS Sustainable Chemistry & Engineering, Год журнала: 2022, Номер 10(40), С. 13335 - 13342

Опубликована: Сен. 28, 2022

Herein, we report a simple catalytic system consisting of CaI2 in combination with Et3N as ligand for the efficient cycloaddition CO2 to variety epoxides. Terminal (bio-based) carbonates were obtained under mild conditions (23 °C, 1 bar pressure) excellent yields up 97%. Under elevated temperature (70 °C) and higher pressure (10 bar), even challenging internal epoxides converted, leading desired 90%. 1H NMR experiments indicated situ coordination amine Lewis acidic calcium center well activation epoxide. Furthermore, enzymatic kinetic resolution seven cyclic using readily available pig liver esterase was investigated. Styrene carbonate proved be most suitable substrate resolution, (R)-styrene 99% ee.

Язык: Английский

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Adenine‐Functionalized Dendritic Fibrous Nanosilica as Bifunctional Catalyst for CO₂ Fixation into Cyclic Carbonate

ChemNanoMat, Год журнала: 2023, Номер 9(4)

Опубликована: Фев. 7, 2023

Abstract Cycloaddition of CO 2 with epoxide to form cyclic carbonate is one the most promising approaches mitigate rising level in atmosphere. Therefore, design and synthesis new materials which can efficiently catalyze such reactions has become an important research area. This article reports on a material, adenine functionalized dendritic fibrous nanosilica ( DAD ), by functionalizing surface DFNS ) N‐containing heterocyclic nucleobase using bifunctional isocyanate crosslinker ((EtO) 3 Si(CH NCO). The amine functionalities enable show selective adsorption (0.44 mmol/g, at 1 bar pressure 298 K temperature) due acid‐base interaction between groups. Moreover, catalyzes fixation variety epoxides into corresponding carbonates presence TBAB (tetrabutylammonium bromide) co‐catalyst under solvent‐free conditions. skeleton offers high area for enhanced adsorption, while its organic groups, carbamide, boost selectivity activate ring cycloaddition reaction. strong covalent linkage groups renders robust structural integrity, enabling catalyst be recycled multiple times negligible reduction catalytic performance.

Язык: Английский

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AI-Driven Insight into Polycarbonate Synthesis from CO2: Database Construction and Beyond

Polymers, Год журнала: 2024, Номер 16(20), С. 2936 - 2936

Опубликована: Окт. 19, 2024

Recent advancements in materials science have garnered significant attention within the research community. Over past decade, substantial efforts been directed towards exploration of innovative methodologies for developing new materials. These encompass enhancements to existing products or processes and design novel Of particular significance is synthesis specific polymers through copolymerization epoxides with CO2. However, several uncertainties emerge this chemical process, including challenges associated successful polymerization properties resulting render a trial-and-error endeavor, often failed outcomes that entail financial, human resource, time investments due unsuccessful experimentation. Artificial Intelligence (AI) emerges as promising technology mitigate these drawbacks during experimental phase. Nonetheless, availability high-quality data remains crucial, posing context polymeric materials, mainly because stochastic nature polymers, which impedes their homogeneous representation, variation based on processing. In study, first dataset linking structure epoxy comonomer, catalyst employed, conditions reaction's success described. A analytical pipeline ML effectively exploit constructed database introduced. The initial results underscore importance addressing dimensionality problem. derived from proposed pipeline, infer molecular weight, polydispersity index, conversion rate, demonstrate adjustment values all target parameters. best are measured terms (Determination Coefficient) R2 between real predicted three magnitudes. solution provides equal 0.79, 0.86, 0.93 respectively. automatized (including AutoML techniques models hyperparameter tuning), allowing easy scalability grows, laying foundation future research.

Язык: Английский

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Molybdenum Complex-Catalyzed N-Alkylation of Bulky Primary and Secondary Amines

The Journal of Organic Chemistry, Год журнала: 2024, Номер 89(22), С. 16510 - 16521

Опубликована: Ноя. 4, 2024

Aliphatic allylic amines are present in a large number of complex and pharmaceutically relevant molecules. The direct amination electrophiles serves as the most common method toward preparation these motifs. However, use feedstock reaction components (allyl alcohol aliphatic amine) transformations remains great challenge. Such challenge primarily stems from high Lewis basicity steric hindrance amines, addition to low reactivity alcohols. Herein, we report general solution challenges. developed protocol allows an efficient allyl alcohols with sterically bulky presence inexpensive earth-abundant molybdenum complex. This simple economic also enables regioselective branched amination; practicality was shown efficient, scaled-up synthesis several drugs.

Язык: Английский

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