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1.
Prashant S. Umare Ajaykumar J. Tiwari Robin Antony Gopal L. Tembe Bhavna Trivedi 《应用有机金属化学》2007,21(8):652-660
Complexes of titanium(IV) with bulky phenolic ligands such as 2‐tert‐butyl‐4 methylphenol, 2, 4‐di‐tert‐butyl phenol and 3,5‐di‐tert‐butyl phenol were prepared and characterized. These catalyst precursors, formulated as [Ti(OPh*)n(OPri)4?n] (OPh* = substituted phenol), were found to be active in polymerization of ethylene at higher temperatures in combination with ethylaluminum sesquichloride (Et3Al2Cl3) as co‐catalyst. It was observed that the reaction temperature and ethylene pressure had a pronounced effect on polymerization and the molecular weight of polyethylene obtained. In addition, this catalytic system predominantly produced linear, crystalline ultra‐low‐molecular‐weight polyethylenes narrow dispersities. The polyethylene waxes obtained with this catalytic system exhibit unique properties that have potential applications in surface coating and adhesive formulations. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
2.
A Self‐Reporting Photocatalyst for Online Fluorescence Monitoring of High Throughput RAFT Polymerization
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Dr. Jonathan Yeow Dr. Sanket Joshi Dr. Robert Chapman Prof. Cyrille Boyer 《Angewandte Chemie (International ed. in English)》2018,57(32):10102-10106
Translating controlled/living radical polymerization (CLRP) from batch to the high throughput production of polymer libraries presents several challenges in terms of both polymer synthesis and characterization. Although recently there have been significant advances in the field of low volume, high throughput CLRP, techniques able to simultaneously monitor multiple polymerizations in an “online” manner have not yet been developed. Here, we report our discovery that 5,10,15,20‐tetraphenyl‐21H,23H‐porphine zinc (ZnTPP) is a self‐reporting photocatalyst that can mediate PET‐RAFT polymerization as well as report on monomer conversion via changes in its fluorescence properties. This enables the use of a microplate reader to conduct high throughput “online” monitoring of PET‐RAFT polymerizations performed directly in 384‐well, low volume microtiter plates. 相似文献
3.
Several mixed ligand complexes of nickel(II) and cobalt(II) acetylacetonates with N-substituted thioureas such as ortho, meta
and para chlorophenyl, parabromophenyl and orthotolyl thioureas and N,N′-substituted thioureas such as N-benzoyl N′-ethyl
thiourea, N-benzoyl N′-phenyl thiourea, N-benzoyl N′-o-chlorophenyl thiourea, N-benzoyl N′-o-tolyl thiourea, N-benzoyl N′-o-methoxyphenyl thiourea, N-benzoyl N′-cyclohexyl thiourea, N-benzoyl N′-2,5 dimethoxyphenyl thiourea, N-benzoyl N′-2,5 diethoxyphenyl
thiourea, N-benzoyl N′-β-hydroxyethyl thiourea, N-benzoyl N′-furfuryl thiourea, N-benzoyl N′-orthohydroxyphenyl thiourea and
N-phenyl N′-orthomethoxyphenyl thiourea, have been synthesized and characterized on the basis of elemental analysis, conductivity,
molecular weight determination and magnetic moments. The nature of the bonding and the structure of the complexes have been
proposed from the infrared and electronic spectral studies. 相似文献
4.
Soluble complexes of group (IV) metallocenes anchored on a substituted polyhedral oligomeric silsesquioxane trisilanol support were prepared and characterized. These catalyst precursors formulated as [M(O^O^O)X] are found to be active in polymerization of ethylene at high temperature in combination with ethylaluminum sesquichloride (Et3Al2Cl3, EASC) as co‐catalyst. The polyethylene obtained by these catalysts is linear, crystalline and displays narrow dispersity. The unique low molecular weight PE formed in this reaction exhibits properties comparable to commercial micronized PE waxes that have potential industrial applications in surface coating and ink formulations. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
5.
Design of Monodisperse and Well‐Defined Polypeptide‐Based Polyvalent Inhibitors of Anthrax Toxin
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Sanket Patke Mohan Boggara Ronak Maheshwari Sunit K. Srivastava Manish Arha Marc Douaisi Jacob T. Martin Ian B. Harvey Matthew Brier Tania Rosen Jeremy Mogridge Prof. Ravi S. Kane 《Angewandte Chemie (International ed. in English)》2014,53(31):8037-8040
The design of polyvalent molecules, presenting multiple copies of a specific ligand, represents a promising strategy to inhibit pathogens and toxins. The ability to control independently the valency and the spacing between ligands would be valuable for elucidating structure–activity relationships and for designing potent polyvalent molecules. To that end, we designed monodisperse polypeptide‐based polyvalent inhibitors of anthrax toxin in which multiple copies of an inhibitory toxin‐binding peptide were separated by flexible peptide linkers. By tuning the valency and linker length, we designed polyvalent inhibitors that were over four orders of magnitude more potent than the corresponding monovalent ligands. This strategy for the rational design of monodisperse polyvalent molecules may not only be broadly applicable for the inhibition of toxins and pathogens, but also for controlling the nanoscale organization of cellular receptors to regulate signaling and the fate of stem cells. 相似文献
6.
Zhao Li Soumil Y. Joshi Yin Wang Prof. Sanket A. Deshmukh Prof. John B. Matson 《Angewandte Chemie (International ed. in English)》2023,62(26):e202303755
We report three constitutionally isomeric tetrapeptides, each comprising one glutamic acid (E) residue, one histidine (H) residue, and two lysine (KS) residues functionalized with side-chain hydrophobic S-aroylthiooxime (SATO) groups. Depending on the order of amino acids, these amphiphilic peptides self-assembled in aqueous solution into different nanostructures:nanoribbons, a mixture of nanotoroids and nanoribbons, or nanocoils. Each nanostructure catalyzed hydrolysis of a model substrate, with the nanocoils exhibiting the greatest rate enhancement and the highest enzymatic efficiency. Coarse-grained molecular dynamics simulations, analyzed with unsupervised machine learning, revealed clusters of H residues in hydrophobic pockets along the outer edge of the nanocoils, providing insight for the observed catalytic rate enhancement. Finally, all three supramolecular nanostructures catalyzed hydrolysis of the l -substrate only when a pair of enantiomeric Boc-l /d -Phe-ONp substrates were tested. This study highlights how subtle molecular-level changes can influence supramolecular nanostructures, and ultimately affect catalytic efficiency. 相似文献
7.
Miniaturized electrochemiluminescence (ECL) systems are widely recognized as a highly detection, user-friendly, and turnkey strategy to develop point-of-care-testing devices. The ECL sensing approach provides numerous advantages over other methods, including high signal-to-noise ratio and measurement with minimal or no background signal. The ECL signal can be easily controlled by a small external potential while providing high sensitivity and decreased electrode fouling, resulting in the use of ECL-based miniaturized systems for detection and monitoring of different analytes, including DNA and bacteria. In this work, different types of miniaturized ECL systems with various fabrication techniques are reviewed and their application in point-of-care-testing is thoroughly discussed. Furthermore, such ECL platforms have been summarized based on the type of the ECL mechanism, electrodes, range of detection, and limit of detection. Finally, some of the upcoming technological interventions to make such a miniaturized ECL platform amenable for portable and on-field analysis have been discussed. 相似文献
8.
Srikanth Sangam Raut Sushil Dubey Satish Kumar Ishii Idaku Javed Arshad Goel Sanket 《The European physical journal. E, Soft matter》2021,44(8):1-19
The European Physical Journal E - Interaction of cytoskeletal filaments, motor proteins, and crosslinking proteins drives important cellular processes such as cell division and cell movement.... 相似文献
9.
Basak A Roy SK Das S Hazra AB Ghosh SC Jha S 《Chemical communications (Cambridge, England)》2007,(6):622-624
The spontaneous activation of a nonaromatic enediynyl azide under ambient conditions has been demonstrated. The aromatic enediyne followed the expected cycloaddition with the alkene in the neighbouring arm to form a stable bridged bicyclic enediyne. 相似文献
10.
A new class of C2-symmetric bis-indole derivatives with 2,2′-linkage has been synthesized from bis-propargyl sulfones. The method involves treatment of the sulfones with catalytic amount of triethylamine to form the indole derivatives presumably via the intramolecular Michael addition to the intermediate bis-allenic sulfones. Interestingly, the expected Garratt-Braverman pathway was not followed. 相似文献