Complete Field Guide to Asymmetric BINOL-Phosphate Derived Brønsted Acid and Metal Catalysis: History and Classification by Mode of Activation; Brønsted Acidity, Hydrogen Bonding, Ion Pairing, and Metal Phosphates

Chemical methods developed over the past two decades enable preparation of colloidal nanocrystals with uniform size and shape. These Brownian objects readily order into superlattices. Recently, the range of accessible inorganic cores and tunable surface chemistries dramatically increased, expanding the set of nanocrystal arrangements experimentally attainable. In this review, we discuss efforts to create next-generation materials via bottom-up organization of nanocrystals with preprogrammed functionality and self-assembly instructions. This process is often driven by both interparticle interactions and the influence of the assembly environment. The introduction provides the reader with a practical overview of nanocrystal synthesis, self-assembly, and superlattice characterization. We then summarize the theory of nanocrystal interactions and examine fundamental principles governing nanocrystal self-assembly from hard and soft particle perspectives borrowed from the comparatively established fields of micro...

Self-Assembly of Colloidal Nanocrystals: From Intricate Structures to Functional Materials

Charged intermediates and reagents are ubiquitous in organic transformations. The interaction of these ionic species with chiral neutral, anionic, or cationic small molecules has emerged as a powerful strategy for catalytic, enantioselective synthesis. This review describes developments in the burgeoning field of asymmetric ion-pairing catalysis with an emphasis on the insights that have been gleaned into the structural and mechanistic features that contribute to high asymmetric induction.

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Asymmetric ion-pairing catalysis.

Ionic Liquids-Based Extraction: A Promising Strategy for theAdvanced Nuclear Fuel Cycle Xiaoqi Sun, Huimin Luo, and Sheng Dai* Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37916, United States State Key Laboratory of Rare Earth Resource Utilization, Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China

Ionic Liquids-Based Extraction: A Promising Strategy for the Advanced Nuclear Fuel Cycle

Monofluorination of Organic Compounds: 10 Years of Innovation.

Development of Real-time Diagnosis Framework for Angular Misalignment of Robot Spot-welding System Based on Machine Learning

Carbon dioxide is arguably one of the most stable carbon-based molecules, yet enzymatic carbon fixation processes enabled the sustainable life cycle on Earth. Chemical reactions involving CO2-functionalization often suffer from low efficiency with highly reactive substrates. We recently reported mild carboxylation of aldehydes to furnish α-keto acids – a building block for chiral α-amino acids via reductive amination. Here, we discuss potential reaction mechanisms of aldehyde carboxylation reactions based on two promoters: NHCs and KCN in the carboxylation reaction. New DFT mechanistic studies suggested a lower reaction barrier for a CO2-functionalization step, implying a potential role of CO2 in prebiotic evolution of organic molecules in the primordial soup. 1 	Introduction: Aldehydes, Benzoins, Carboxylic Acids 2 	CO2-Activation: NHC, Cyanide, Lewis Acid and Water 3 	A Breslow Intermediate: Benzoin Reaction vs. Carboxylation with CO2
 4 	Carboxylation in the Primordial Soup 5 	Conclusion

Aldehyde Carboxylation: A Concise DFT Mechanistic Study and a Hypothetical Role of CO2 in the Origin of Life

Self-association-free, bifunctional, squaramide-based dimeric cinchona alkaloid organocatalysts show unprecedented catalytic activity, enantioselectivity and catalyst recyclability in the dynamic kinetic resolution (DKR) reaction of a broad range of racemic azlactones.

Self‐Association‐Free Dimeric Cinchona Alkaloid Organocatalysts: Unprecedented Catalytic Activity, Enantioselectivity and Catalyst Recyclability in Dynamic Kinetic Resolution of Racemic Azlactones.

ConspectusAsymmetric cation-binding catalysis in principle enables the use of (alkali) metal salts, otherwise insoluble in organic solvents, as reagents and effectors in enantioselective reactions. However, this concept has been a formidable challenge due to the difficulties associated with creating a highly organized chiral environment for cations and anions simultaneously. Over the last four decades, various chiral crown ethers have been developed as cation-binding phase-transfer catalysts and examined in asymmetric catalysis. However, the limited ability of chiral crown ethers to generate soluble reactive anions in a confined chiral cage offers a restricted reaction scope and unsatisfactory chirality induction. To address the constraints of monofunctional chiral crown ethers as cation-binding catalysts, it is therefore desirable to develop a cooperative cation-binding catalyst possessing secondary binding sites for anions, which enables the generation of a reactive anion within a chiral cage of a catalyst. This account summarizes our design, development, and applications of chiral BINOL-based oligoethylene glycols (oligoEGs) as a new type of bifunctional cation-binding catalyst. We initially found that achiral oligoEGs were efficient promoters in nucleophilic fluorination with potassium fluoride. Thereby, we hypothesized that, by breaking the closed cyclic ether unit of chiral crown ethers, the free terminal -OH groups could activate the electrophiles by hydrogen bonding whereas the ether oxygens could act as the Lewis base to coordinate metal ions, thus generating soluble anions in a confined chiral cage. This hypothesis was realized by synthesizing a series of chiral variants of oligoEGs by connecting two 3,3'-disubstituted-BINOL units with glycol linkers. Readily available BINOL-based chiral oligoEGs enabled numerous asymmetric transformations out of the reach of chiral monofunctional crown ether catalysts. We have demonstrated that this new type of bifunctional cation-binding catalysts can generate a soluble fluoride anion from alkali metal fluorides, which can be a versatile chiral promoter for diverse asymmetric catalytic reactions, kinetic resolution (selectivity factor of up to ∼2300), asymmetric protonation, Mannich reactions, tandem cyclization reactions, and the isomerization of allylic alcohols and hemithioacetals. We have also successfully utilized our chiral oligoEG catalysts along with alkali metal salts of carbon- and heteroatom-based nucleophiles, respectively, for asymmetric Strecker reactions and the asymmetric synthesis of chiral aminals. The power of our cooperative cation-binding catalysis was exemplified by kinetic resolution reactions of secondary alcohols, achieving highly enantioselective catalysis with only <1 ppm loading of an organocatalyst with high TOFs (up to ∼1300 h-1 at 1 ppm catalyst loading). The broadness and generality of our cooperative asymmetric cation-binding catalysis can be ascribed, in a similar fashion, to active-site architectures of enzymes using allosteric interactions, highly confined chiral cages formed by the incorporation of alkali metal salts in the catalyst polyether chain backbone, and the cooperative activation of reacting partners by hydrogen-bonding and ion-ion interactions. Confining reactive components in such a chiral binding pocket leads to enhanced reactivity and efficient transfer of the stereochemical information.

Cooperative Asymmetric Cation-Binding Catalysis.

Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission. 1 Abstract— We develop a new kind of fully distributed random backoff algorithm which completely removes collisions in a single channel carrier-sense multiple access based network without any assistance from a centralized coordination function. Based on carefully chosen design objectives, three principles are established to contribute to the design of the zero-collision achieving random backoff algorithm, which is dubbed as ZeroCollision. To find non-colliding access slots, a station learns from its past transmission history and from neighbors' activities. By building sufficient statistics for its access decision, the station is guaranteed to avoid collisions. By preventing collisions, the network performance is enhanced in terms of primary performance metrics such as throughput and transmission delay in comparison to the generic exponential backoff algorithm. We also analyze the VoIP capacity on top of the IEEE 802.11b PHY/MAC and show that the ZeroCollision algorithm supports maximally 54 users which is approximately 400 percent larger than the exponential backoff algorithm.

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Ji-Woong Lee

Papers

Development of Real-time Diagnosis Framework for Angular Misalignment of Robot Spot-welding System Based on Machine Learning

Aldehyde Carboxylation: A Concise DFT Mechanistic Study and a Hypothetical Role of CO2 in the Origin of Life

Self‐Association‐Free Dimeric Cinchona Alkaloid Organocatalysts: Unprecedented Catalytic Activity, Enantioselectivity and Catalyst Recyclability in Dynamic Kinetic Resolution of Racemic Azlactones.

Cooperative Asymmetric Cation-Binding Catalysis.

ZeroCollision Random Backoff Algorithm