نتایج جستجو برای: cyclic olefin polymer
تعداد نتایج: 192668 فیلتر نتایج به سال:
A valuable approach for creating synthetic polymers is the ring-opening metathesis polymerization (ROMP). Welldefined metal carbene catalysts have been devised that afford control over the polymer chain length and architecture. In addition, ruthenium carbene initiators have been developed with excellent air stability and functional group tolerance. These catalysts enable the synthesis of polyme...
The electrochemical behavior of the cation exchange polymer Nation containing tetrathiafulvalenium (TTF +) on a platinum sub strate is described. The polymer electrode shows cyclic voltammetric behavior similar to that of solid films of TTF on platinum. In 1.0M KBr the oxidized form of the electroactive molecules in the polymer (TTF § forms nonstoichiometric complexes with Br-. The peak potenti...
The development of a model system to study ruthenium-olefin complexes relevant to the mechanism of olefin metathesis is reported. Upon addition of 1,2-divinylbenzene to (H2IMes)(py2)(Cl)2Ru=CHPh (H2IMes = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene), two ruthenium-olefin adducts are formed. On the basis of 1H NMR spectroscopy experiments and X-ray crystallographic analysis, these complexes are ...
Dinuclear ruthenium complex, with a bridging carbide and a hydride ligand, and methyltricyclohexylphosphonium chloride result from thermal decomposition of olefin metathesis catalyst, (IMesH2)(PCy3)(Cl)2Ru=CH2. Involvement of dissociated phosphine in the decomposition is proposed. The dinuclear complex has catalytic olefin isomerization activity, which can be responsible for competing isomeriza...
A solid-phase synthesis of glycopeptoids was explored through olefin cross metathesis (CM). Peptoids and sugar derivatives with appropriate olefin moieties were coupled in the presence of an olefin metathesis catalyst to afford glycopeptoids in good yields. This systematic solid-phase CM study can provide facile access to the molecular sources of glycopeptidomimetics and postchemical modificati...
Cyclic polymer brush topology prevents gold nanoparticle sedimentation ensuring long-term colloidal stability in ethanol at −25 °C.
Cytochrome c (cyt c)-immobilized monolayers and multiple monolayers of a conducting polymer [poly(terthiophene-3-carboxylic acid) polymer (poly-TTCA)] were prepared, where the monolayer of monomer precursor was fabricated with the Langmuir-Blogett technique. Covalent immobilization of cyt c was achieved by the formation of an amide bond between the carboxylic groups of the conducting polymer an...
We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single molecule level. An electrostatic self-assembly and covalent fixation (ESA-CF) process is used for the synthesis of the cyclic poly(tetrahydrofuran) (poly(THF)). The diffusive motion of individual cyclic polymer chains in a melt state is visualized u...
Microorganisms can be engineered for the production of chemicals utilized in the polymer industry. However many such target compounds inhibit microbial growth and might correspondingly limit production levels. Here, we focus on compounds that are precursors to bioplastics, specifically styrene and representative alpha-olefins; 1-hexene, 1-octene, and 1-nonene. We evaluated the role of the Esche...
Dinuclear nickelphenoxyiminato olefin polymerization catalysts based on rigid p-terphenyl frameworks are reported. Permethylation of the central arene of the terphenyl unit and oxygen substitution of the peripheral rings ortho to the aryl-aryl linkages blocks rotation around these linkages allowing atropisomers of the ligand to be isolated. The corresponding syn and anti dinickel complexes (25-...
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