Millie
your market intelligence analyst
Search Results
Edit Save
7,252 results
The precise control of monomer sequence and stereochemistry in copolymerization is of much interest and importance for the synthesis of functional polymers, but studies toward this goal have met with only limited success to date. We report herein the co‐syndiospecific alternating copolymerization of methoxyphenyl‐ and N , N ‐dimethylaminophenyl‐functionalized propylenes with styrene by half‐sandwich rare‐earth catalysts. This reaction efficiently afforded the corresponding functionalized propylene− alt −styrene copolymers with a perfect alternating sequence and excellent co‐syndiotacticity ( rrrr > 99%), thus constituting the first example of co‐stereospecific alternating copolymerization of polar and non‐polar olefins.
In Mycobacterium tuberculosis, mycolic acids and their glycerol, glucose, and trehalose esters (“cord factor”) form the main part of the mycomembrane. Despite their first isolation almost a century ago, full stereochemical evaluation is lacking, as is a scalable synthesis required for accurate immunological, including vaccination, studies. Herein, we report an efficient, convergent, gram‐scale synthesis of four stereo‐isomers of a mycolic acid and its glucose ester. Binding to the antigen presenting protein CD1b and T cell activation studies are used to confirm the antigenicity of the synthetic material. The absolute stereochemistry of the syn ‐methoxy methyl moiety in natural material is evaluated by comparing its optical rotation with tha.
The accumulation and deposition of β‐amyloid ( Aβ ) plaques in the brain is considered one of the potential pathogenic mechanisms underlying Alzheimer’s disease (AD) . In this study, chiral l/d‐Fe x Cu y Se nanoparticles (l/d‐NPs) were fabricated that showed three characteristic peaks at 435, 515, and 780 nm (in the range of 400‐1,000 nm) on circular dichroism (CD) spectra. We demonstrated that these chiral l/d‐NPs interfered with the self‐assembly of Aβ42 monomers and triggered the Aβ42 fibrils in dense structures to become looser monomers under 808 nm near‐infrared (NIR) illumination. Our data showed that d‐ Fe x Cu y Se NPs had a much higher affinity for Aβ42 fibrils than l‐Fe x Cu y Se NPs and chiral Cu 2‐x Se NPs. The chiral Fe x Cu y
Layered lithium‐rich cathode materials have attracted extensive interests owing to their high theoretical specific capacity (320 ‐ 350 mA h g −1 ). However, poor cycling stability and sluggish reaction kinetics inhibit their practical applications. After many years of quiescence, it is expected to revive the development of layered lithium‐rich cathode materials to resolve our increasing dependence on high‐energy‐density lithium‐ion batteries. Herein, we reviewed recent research progresses and in‐depth understandings of structure characterizations and reaction mechanisms of layered lithium‐rich manganese‐based cathode materials. In particular, we comprehensively summarized the proposed reaction mechanisms on both the cationic redox reaction
Miniaturized autonomous chemo‐electronic swimmers, based on the coupling of spontaneous oxidation and reduction reactions at the two poles of light emitting diodes (LEDs), are presented as chemotactic and magnetotactic devices. In homogeneous aqueous media, random motion caused by a bubble‐induced propulsion mechanism, is observed. However, in an inhomogeneous environment, the self‐propelled devices exhibit positive chemotactic behavior, propelling themselves along a pH or ionic strength gradient (ÑpH, ÑI, respectively) in order to reach a thermodynamically higher active state. In addition, the intrinsic permanent magnetic moment of the LED allows self‐orientation in the terrestrial magnetic field or following other external magnetic pertur.
A series of BN‐embedded oligomers with different pairs of BN units have been successfully synthesized through electrophilic borylation processes. Organolithium intermediate is avoided in this approach and thus multiple pairs of BN units up to four have been facilely incorporated in the large polycyclic aromatic hydrocarbons (PAHs). Their geometric, photophysical, electrochemical, and Lewis acidic properties have been systematically investigated by X‐ray crystallography, optical spectroscopy, and cyclic voltammetry measurements. It is found that the B‐N bonds show delocalized double‐bond characteristics and the conjugation can be extended through the trans‐orientated aromatic azaborine units. Further theoretical calculations reveal the relat.
Atomic co‐catalysts offer high potential to improve the photocatalytic water splitting performance, while the preparation of atomic co‐catalysts with earth‐abundant elements remains challenging. In this work, a new molten salt method (MSM) is designed to prepare atomic Ni co‐catalyst on widely studied TiO 2 nanoparticles. The liquid environment and space confinement effect of the molten salt lead to atomic dispersion of Ni ions on TiO 2 , while the strong polarizing force provided by the molten salt promotes the formation of strong Ni‐O bonds. Interestingly, it is found that Ni atoms facilitate the formation of oxygen vacancies on the neighbouring surface of TiO 2 during the MSM process, which benefits the charge transfer and hydrogen evolu.
We report that Ni(COD)(DQ) (COD = 1,5‐cyclooctadiene, DQ = duroquinone), an air‐stable 18‐electron complex originally described by Schrauzer in 1962, is a competent precatalyst for a variety of nickel‐catalyzed synthetic methods from the literature. Due to its apparent stability, use of Ni(COD)(DQ) as a precatalyst allows reactions to be conveniently performed without use of an inert‐atmosphere glovebox, as demonstrated across several case studies.
Multimodal Catalysis I. S. Lee et al. describe in their Communication on page 3416 the rational integration of three different catalytic modalities—metal cations, heterogeneous metal nanocrystals, and enzymes—within the same mesopore of MOFs for a multistep divergent cascade.
Noble‐metal chalcogenides, dichalcogenides and phosphochalcogenides are an emerging class of two‐dimensional materials. Their properties can be broadly tuned via quantum confinement (number of layers) and defect engineering, including metal‐to‐semiconductor transitions, magnetic ordering, and topological surface states. They possess various polytypes, often of similar formation energy, which can be assessed by selective synthesis approaches. They excel in mechanical, optical and chemical sensing applications, and feature long‐term air‐ and moisture stability. In this review, we summarize the recent progress in the field of noble metal chalcogenides and phosphochalcogenides and highlight the structural complexity and its impact on applicatio.
The Pauling rules have been used for decades to rationalize the crystal structures of ionic compounds. Despite their importance, there has been so far no statistical assessment of the performances of these five empirical rules. Here, we test rigorously and automatically all five Pauling rules for a large data set of around 5000 known oxides. We discuss each Pauling rule separately stressing their limits and range of application in terms of chemistries and structures. We conclude that only 13% of the oxides simultaneously satisfy the last four rules, indicating their much lower predictive power than expected.
Photosynthetic biohybrid systems have emerged as a promising platform for solar‐to‐chemical conversion by integrating excellent light‐harvesting ability of semiconductors with the synthetic capability of biological cells. How to enhance the utilization of solar energy, hole/electron separation efficiency and the electron transfer between the semiconductor and biological cells is crucial to develop high‐performance photosynthesis platforms. In this work, we developed an organic semiconductor−bacteria biohybrid photosynthetic system, which could efficiently realize CO 2 reduction to produce acetic acid through non‐photosynthetic bacteria Moorella thermoacetica . As the photosensitizers, both cationic electron‐transporting ( n ‐type) perylene
Sulfur‐based homolytic substitution (SH) plays an important role in synthetic chemistry, yet whether such a chemistry could occur on the positively charged sulfonium compounds remains unknown. In the study of the anaerobic coproporphyrinogen III oxidase HemN, a radical S‐adenosyl‐L‐methionine (SAM) enzyme involved in Heme biosynthesis, we observed the production of di‐(5′‐deoxyadenosyl)methylsulfonium, supporting a deoxyadenosyl (dAdo) radical‐mediated SH reaction on the sulfonium center of SAM. The sulfonium‐based SH reactions were then investigated in detail by density functional theory calculations and by model reactions, showing that such a type of reactions is thermodynamically favorable and kinetically competent. These findings repres.
The encapsulation of copper inside a cyclodextrin capped with a N ‐heterocyclic carbene (ICyD) allowed both to catch the elusive monomeric (L)Cu‐H and a cavity‐controlled chemoselective copper‐catalyzed hydrosilylation of α,β ‐unsaturated ketones. Remarkably, ( α ‐ICyD)CuCl promoted exclusively the 1,2‐addition, while ( β ‐ICyD)CuCl produced the totally reduced product. The chemoselectivity is controlled by the size of the cavity and weak‐interactions between the substrate and internal C‐H of the cyclodextrin.
Nonaromatic, cross‐conjugated, and highly twisted luminogens consisting of acylated succinimides demonstrate aggregation‐induced emission characteristics and tunable multicolor photoluminescence and afterglows in their single crystals. Effective through‐space conjugation among different moieties bearing n/π electrons promote the spin orbit coupling and intersystem crossing transitions and lead to diverse emissive clusters with concurrently rigidified conformations, thus allowing readily tunable emissions. Derived from it, the proof of concept application for advanced anti‐counterfeiting is illustrated. These results should spur the rational design of novel nonaromatic AIEgens, and moreover advance understandings of the non‐traditional intri.
1,2‐Bisphosphines have been identified as one class of important and powerful chiral ligands in asymmetric catalysis with transition metals. Herein, a copper(I)‐catalyzed asymmetric hydrophosphination of α,β‐unsaturated phosphine sulfides was developed with the assistance of “soft‐soft interaction” between copper(I)‐catalyst and the phosphine sulfide moiety, which afforded 1,2‐bisphosphine derivatives with diversified electronic nature and steric hindrance in high to excellent yields with high to excellent enantioselectivity. Moreover, the challenging catalytic asymmetric hydrophosphination/protonation reaction was achieved with excellent enantioselectivity. Strikingly, the dynamic kinetic resolution of racemic diarylphosphines was also suc.

Automotive Industries

Business Issues

Companies - Public

Companies - Venture Funded

Global Markets

Government Agencies

Information Technologies

Job Titles

Legal and Regulatory

Market Research Topics

Political Entities

Sources

Strategic Scenarios

Trends