scholarly journals Rollover Cyclometalation as a Valuable Tool for Regioselective C–H Bond Activation and Functionalization

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 328
Author(s):  
Antonio Zucca ◽  
Maria I. Pilo
Keyword(s):  
Internal Rotation ◽  
Bond Activation ◽  
Advanced Materials ◽  
Donor Atom ◽  
Bidentate Coordination ◽  
Heterocyclic Ligand ◽  
Cyclometalated Complex ◽  
Potential Applications ◽  
Cyclometalated Complexes ◽  
The One

Rollover cyclometalation constitutes a particular case of cyclometallation reaction. This reaction occurs when a chelated heterocyclic ligand loses its bidentate coordination mode and undergoes an internal rotation, after which a remote C–H bond is regioselectively activated, affording an uncommon cyclometalated complex, called “rollover cyclometalated complex”. The key of the process is the internal rotation of the ligand, which occurs before the C−H bond activation and releases from coordination a donor atom. The new “rollover” ligand has peculiar properties, being a ligand with multiple personalities, no more a spectator in the reactivity of the complex. The main reason of this peculiarity is the presence of an uncoordinated donor atom (the one initially involved in the chelation), able to promote a series of reactions not available for classic cyclometalated complexes. The rollover reaction is highly regioselective, because the activated C–H bond is usually in a symmetric position with respect to the donor atom which detaches from the metal stating the rollover process. Due to this novel behavior, a series of potential applications have appeared in the literature, in fields such as catalysis, organic synthesis, and advanced materials.

OnPoint: A package for online experiments in motor control and motor learning

2020 ◽  
Author(s):  
Jonathan Sanching Tsay ◽  
Alan S. Lee ◽  
Guy Avraham ◽  
Darius E. Parvin ◽  
Jeremy Ho ◽  
...  
Keyword(s):  
Motor Control ◽  
Motor Learning ◽  
Open Source Software ◽  
Research Progress ◽  
Global Pandemic ◽  
Large N ◽  
Open Source Software Package ◽  
Potential Applications ◽  
Temporal And Spatial ◽  
The One

Motor learning experiments are typically run in-person, exploiting finely calibrated setups (digitizing tablets, robotic manipulandum, full VR displays) that provide high temporal and spatial resolution. However, these experiments come at a cost, not limited to the one-time expense of purchasing equipment but also the substantial time devoted to recruiting participants and administering the experiment. Moreover, exceptional circumstances that limit in-person testing, such as a global pandemic, may halt research progress. These limitations of in-person motor learning research have motivated the design of OnPoint, an open-source software package for motor control and motor learning researchers. As with all online studies, OnPoint offers an opportunity to conduct large-N motor learning studies, with potential applications to do faster pilot testing, replicate previous findings, and conduct longitudinal studies (GitHub repository: https://github.com/alan-s-lee/OnPoint).

scholarly journals Advances in Synthesis of π-Extended Benzosilole Derivatives and Their Analogs

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 548
Author(s):  
Tuan Thanh Dang ◽  
Hue Minh Thi Nguyen ◽  
Hien Nguyen ◽  
Tran Ngoc Dung ◽  
Minh Tho Nguyen ◽  
...  
Keyword(s):  
Solar Cells ◽  
Physical Properties ◽  
Electronic Materials ◽  
Advanced Materials ◽  
Potential Applications

Benzosiloles and their π-extended derivatives are present in many important advanced materials due to their excellent physical properties. Especially, they have found many potential applications in the development of novel electronic materials such as OLEDs, semiconductors and solar cells. In this review, we have summarized several main approaches to construct (di)benzosilole derivatives and (benzo)siloles fused to aromatic five- and six-membered heterocycles.

scholarly journals Topological guided-mode resonances at non-Hermitian nanophotonic interfaces

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ki Young Lee ◽  
Kwang Wook Yoo ◽  
Youngsun Choi ◽  
Gunpyo Kim ◽  
Sangmo Cheon ◽  
...  
Keyword(s):  
Fundamental Study ◽  
One Dimensional ◽  
Guided Mode ◽  
Wall Structures ◽  
Potential Applications ◽  
Photonic Microstructures ◽  
Guided Mode Resonance ◽  
The One ◽  
Photonic Band ◽  
Topological Correlations

Abstract The topological properties of photonic microstructures are of great interest because of their experimental feasibility for fundamental study and potential applications. Here, we show that robust guided-mode-resonance states exist in photonic domain-wall structures whenever the complex photonic band structures involve certain topological correlations in general. Using the non-Hermitian photonic analogy of the one-dimensional Dirac equation, we derive essential conditions for photonic Jackiw-Rebbi-state resonances taking advantage of unique spatial confinement and spot-like spectral features which are remarkably robust against random parametric errors. Therefore, the proposed resonance configuration potentially provides a powerful method to create compact and stable photonic resonators for various applications in practice.

scholarly journals A Textile Waste Fiber-Reinforced Cement Composite: Comparison between Short Random Fiber and Textile Reinforcement

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3742
Author(s):  
Payam Sadrolodabaee ◽  
Josep Claramunt ◽  
Mònica Ardanuy ◽  
Albert de la Fuente
Keyword(s):  
Construction Material ◽  
Drying Shrinkage ◽  
Cement Composite ◽  
Nonwoven Fabric ◽  
Textile Waste ◽  
Nonwoven Fabrics ◽  
Potential Applications ◽  
Reinforced Cement ◽  
The One ◽  
Garment And Textile

Currently, millions of tons of textile waste from the garment and textile industries are generated worldwide each year. As a promising option in terms of sustainability, textile waste fibers could be used as internal reinforcement of cement-based composites by enhancing ductility and decreasing crack propagation. To this end, two extensive experimental programs were carried out, involving the use of either fractions of short random fibers at 6–10% by weight or nonwoven fabrics in 3–7 laminate layers in the textile waste-reinforcement of cement, and the mechanical and durability properties of the resulting composites were characterized. Flexural resistance in pre- and post-crack, toughness, and stiffness of the resulting composites were assessed in addition to unrestrained drying shrinkage testing. The results obtained from those programs were analyzed and compared to identify the optimal composite and potential applications. Based on the results of experimental analysis, the feasibility of using this textile waste composite as a potential construction material in nonstructural concrete structures such as facade cladding, raised floors, and pavements was confirmed. The optimal composite was proven to be the one reinforced with six layers of nonwoven fabric, with a flexural strength of 15.5 MPa and a toughness of 9.7 kJ/m2.

Three-Dimensional Microfabrication System for Biodegradable Microdevices With High-Resolution and Bio-Applicability

2005 ◽  
Author(s):  
Akira Yamada ◽  
Fuminori Niikura ◽  
Koji Ikuta
Keyword(s):  
Tensile Strength ◽  
Biodegradable Polymers ◽  
Conventional Method ◽  
Three Dimensional ◽  
Single Layer ◽  
Batch Process ◽  
Potential Applications ◽  
A Cell ◽  
The One ◽  
Almost All

Biodegradable polymers are employed in medicine and its further application is expected with eagerness. But the lack of an appropriate processing method retards the progress. To overcome this problem, we have developped a novel three-dimensional microfabrication system. The system design allows us the processing of the free three-dimensional micro-level forms by stacking up melted polymers from the nozzle. Different from the conventional method, we adopted a batch process to supply materials in order to eliminate the prior process that required toxic solvents. In addition, it is possible to handle almost all biodegradable thermoplastic resins by adopting this system. A single layer from the piled-up layers of extruded lines was observed to evaluate the resolution. The lateral and depth resolutions attained are 40 μm and 45 μm, respectively. Biodegradable polymers enable three-dimensional microstructures such as micro-pipes, micro-bends, and micro-coil springs to be manufactured in less than 15 min. The biocompatibility of the newly fabricated structure was evaluated using a cell line (PC12). For this purpose, a small vessel, with a transparent base, was fabricated using PLA and cells were cultivated in it. The results were then compared with the results obtained using the standard method. The mechanical strength of our microstructures was evaluated using a tensile strength test. The tensile strength of the microstructure was lower than the one obtained from the conventional method, but has enough strength for fabrication of medical devices. Our system renders it possible to produce toxic-free, as well as transparent and leakage-free devices. Our system is expected to have potential applications in optimum design and fabrication of implantable devices, especially in tissue engineering.

scholarly journals Rare Earth Elements Enhanced the Oxidation Resistance of Mo-Si-Based Alloys for High Temperature Application: A Review

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1144
Author(s):  
Laihao Yu ◽  
Yingyi Zhang ◽  
Tao Fu ◽  
Jie Wang ◽  
Kunkun Cui ◽  
...  
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Rare Earth Elements ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Strengthening Mechanism ◽  
Advanced Materials ◽  
Performance Requirements ◽  
Large Numbers ◽  
The One

Traditional refractory materials such as nickel-based superalloys have been gradually unable to meet the performance requirements of advanced materials. The Mo-Si-based alloy, as a new type of high temperature structural material, has entered the vision of researchers due to its charming high temperature performance characteristics. However, its easy oxidation and even “pesting oxidation” at medium temperatures limit its further applications. In order to solve this problem, researchers have conducted large numbers of experiments and made breakthrough achievements. Based on these research results, the effects of rare earth elements like La, Hf, Ce and Y on the microstructure and oxidation behavior of Mo-Si-based alloys were systematically reviewed in the current work. Meanwhile, this paper also provided an analysis about the strengthening mechanism of rare earth elements on the oxidation behavior for Mo-Si-based alloys after discussing the oxidation process. It is shown that adding rare earth elements, on the one hand, can optimize the microstructure of the alloy, thus promoting the rapid formation of protective SiO2 scale. On the other hand, it can act as a diffusion barrier by producing stable rare earth oxides or additional protective films, which significantly enhances the oxidation resistance of the alloy. Furthermore, the research focus about the oxidation protection of Mo-Si-based alloys in the future was prospected to expand the application field.

scholarly journals Synthesis of BODIPY-Amino Acids and the Potential Applications as Specific Dyes for the Cytoplasm of Langerhans β-Cells

2021 ◽  
Author(s):  
Jorge Aguilera ◽  
Víctor García-González ◽  
Manuel Alatorre-Meda ◽  
Eustolia Rodríguez-Velázquez ◽  
Ignacio Rivero
Keyword(s):  
Amino Acids ◽  
Photophysical Properties ◽  
Fluorescence Emission ◽  
Dual Fluorescence ◽  
Β Cells ◽  
Cell Cytoplasm ◽  
Specific Staining ◽  
Cell Staining ◽  
Potential Applications ◽  
The One

In this work, we explored the synthesis of 4,4-difluoro-4-bora-3a,4a-diazas-indacene (BODIPYs) bound to five different amino acids (BODIPY-FAA) (glycine, alanine, leucine, phenylalanine, and tyrosine) (amino group is kept protected with fluorophore Fmoc) and evaluated these conjugates in terms of (i) their photophysical properties and (ii) their potential application as cell staining agents of suspension and adherent cells at healthy and stress conditions. In general, all synthesized BODIPY-FAA (3a-3e) were found to emit fluorescence in the blue and green regions of the spectrum (depending on the solvent conditions). However, BODIPY-FTyr(trt) (3e) showed the best molar extinction coefficient (ε = 28,198 M-1 cm-1) and quantum yield (Φ = 0.17). Biologically speaking, all synthesized conjugates demonstrated a selective affinity for the cytoplasm of Langerhans β-cells employed as a model, being the BODIPY-FLeu conjugate the one displaying the highest observed intensity. As such, our results reveal the BODIPY-FAA as a novel attractive tool for the specific staining of the cell cytoplasm, demonstrating not only a dual fluorescence emission but also a sensing capability to recognize different cell states.

Arene C–H bond activation and methane formation by a methylplatinum(ii) complex: experimental and theoretical elucidation of the mechanism

2019 ◽  
Vol 43 (21) ◽  
pp. 8005-8014 ◽  
Author(s):  
Asma Nahaei ◽  
S. Masoud Nabavizadeh ◽  
Fatemeh Niroomand Hosseini ◽  
S. Jafar Hoseini ◽  
Mahdi M. Abu-Omar
Keyword(s):  
Bond Activation ◽  
Oxidative Addition ◽  
Methane Formation ◽  
Donor Atom ◽  
Computational Investigation ◽  
Hydride Complex

A combined experimental/computational investigation reveals that the cyclometalation of [PtMe2(DMSO)2], 1, by HC^N ligands proceeds via HC^N coordination through the N donor atom, oxidative addition of the arene C–H bond, and final dissociation of methane from a platinum hydride complex.

scholarly journals Some New Fractional-Calculus Connections between Mittag–Leffler Functions

Mathematics ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 485 ◽  
Author(s):  
Hari M. Srivastava ◽  
Arran Fernandez ◽  
Dumitru Baleanu
Keyword(s):  
Experimental Data ◽  
Fractional Calculus ◽  
Fractional Derivative ◽  
Fractional Integral ◽  
Integral Expression ◽  
Potential Applications ◽  
The One ◽  
Two Parameter

We consider the well-known Mittag–Leffler functions of one, two and three parameters, and establish some new connections between them using fractional calculus. In particular, we express the three-parameter Mittag–Leffler function as a fractional derivative of the two-parameter Mittag–Leffler function, which is in turn a fractional integral of the one-parameter Mittag–Leffler function. Hence, we derive an integral expression for the three-parameter one in terms of the one-parameter one. We discuss the importance and applications of all three Mittag–Leffler functions, with a view to potential applications of our results in making certain types of experimental data much easier to analyse.

Computerized Fieldwork Data Base: Applications and Implications

1987 ◽  
Vol 54 (5) ◽  
pp. 263-267 ◽  
Author(s):  
Helen Polatajko ◽  
Marilyn Ernest ◽  
Joyce MacKinnon
Keyword(s):  
Data Base ◽  
Educational Programs ◽  
The Other ◽  
Other Hand ◽  
Resultant Data ◽  
Potential Applications ◽  
The One ◽  
The University ◽  
Professional Judgement

Fieldwork placement is a complicated and involved task. On the one hand, it requires insightful, professional judgement, but on the other hand, it includes numerous routine administrative and clerical tasks. To deal with fieldwork placement more efficiently and effectively it was decided to computerize the fieldwork placement system at the University of Western Ontario, London, Ontario. This paper describes the system developed and the resultant data base. The potential applications of the data base and the implications for students, facilities, educational programs, professional governing bodies and research are discussed.

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