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Copper(0)-mediated Reversible-deactivation Radical Polymerization
Copper(0)-mediated reversible-deactivation radical polymerization (Cu(0)-mediated RDRP) is a member of the class of reversible-deactivation radical polymerization. As the name implies, metallic copper is employed as the transition-metal catalyst for reversible activation/deactivation of the propagating chains responsible for uniform polymer chain growth. History of Copper-mediated RDRP Although copper complexes (in combination with relevant ligands) have long been used as catalysts for organic reactions such as atom transfer radical addition (ATRA) and copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC), copper complex catalyzed RDRP was not reported until 1995 when Jin-Shan Wang and Krzysztof Matyjaszewski introduced it as atom transfer radical polymerization (ATRP). ATRP with copper as catalyst quickly became one of the most robust and commonly used RDRP techniques for designing and synthesizing polymers with well-defined composition, functionalities, and architecture. Due ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reversible-deactivation Radical Polymerization
Reversible deactivation radical polymerizations (RDRPs) are members of the class of reversible deactivation polymerizations which exhibit much of the character of living polymerizations, but cannot be categorized as such as they are not without chain transfer or chain termination reactions. Several different names have been used in literature, which are: *Living radical polymerization *Living free radical polymerization *Controlled/"living" radical polymerization *Controlled radical polymerization *Reversible deactivation radical polymerization Though the term "living" radical polymerization was used in early days, it has been discouraged by IUPAC, because radical polymerization cannot be a truly living process due to unavoidable termination reactions between two radicals. The commonly used term controlled radical polymerization is permitted, but reversible-deactivation radical polymerization or controlled reversible-deactivation radical polymerization (RDRP) is recommended. Histor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement. Copper is one of the few metals that can occur in nature in a directly usable metallic form (native metals). This led to very early human use in several regions, from circa 8000 BC. Thousands of years later, it was the first metal to be smelted from sulfide ores, circa 5000 BC; the first metal to be cast into a shape in a mold, c. 4000 BC; and the first metal to be purposely alloyed with another metal, tin, to create br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition-metal Catalyst
In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. They are the elements that can use d orbitals as valence orbitals to form chemical bonds. The lanthanide and actinide elements (the f-block) are called inner transition metals and are sometimes considered to be transition metals as well. Since they are metals, they are lustrous and have good electrical and thermal conductivity. Most (with the exception of group 11 and group 12) are hard and strong, and have high melting and boiling temperatures. They form compounds in any of two or more different oxidation states and bind to a variety of ligands to form coordination complexes that are often coloured. They form many useful alloys and are often employed as catalysts in elemental form or in compounds such as coordination complexes and oxides. Most are strongly paramagn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propagating Chain
Chain propagation (sometimes referred to as propagation) is a process in which a reactive intermediate is continuously regenerated during the course of a chemical chain reaction. For example, in the chlorination of methane, there is a two-step propagation cycle involving as chain carriers a chlorine atom and a methyl radical IUPAC Gold Book which are regenerated alternately: :•Cl + CH4 → HCl + •CH3 :•CH3 + Cl2 → CH3Cl + •Cl The two steps add to give the equation for the overall chain reaction: :CH4 + Cl2 → CH3Cl + HCl. Polymerization In a |
Jin-Shan Wang
Jin-Shan Wang (; born July 6, 1962), is a Chinese-American organic chemist and entrepreneur. Biography Wang was born in Jiangyan, Jiangsu, China in 1962. Wang obtained his bachelor's (in 1982) and master's (in 1985) degrees both in polymer science from the East China University of Science and Technology. In 1989, Wang went to study in Belgium with Prof. Philippe Teyssié and obtained his doctorate degree with highest possible rank (avec la plus grande distinction et les felicitations du jury) from the University of Liège, Belgium, in 1993. Wang published more than 20 papers, mostly in Macromolecules, and obtained 12 issued US and European patents in the area of living polymerization from his four-years doctoral research work. Months before his departure to the United States to continue his research at the Carnegie Mellon University with Krzysztof Matyjaszewski in 1994, he started conceptualizing free-radical catalyzed living radical polymerization, after studying a seri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Krzysztof Matyjaszewski
Krzysztof "Kris" Matyjaszewski (; born April 8, 1950) is a Polish-American chemist. He is the J.C. Warner Professor of the Natural Sciences at the Carnegie Mellon University Matyjaszewski is best known for the discovery of atom transfer radical polymerization (ATRP), a novel method of polymer synthesis that has revolutionized the way macromolecules are made. Matyjaszewski was elected a member of the National Academy of Engineering in 2006 and the National Academy of Sciences in 2019 for expanding the capabilities of controlled/living polymerizations and developing ATRP, a robust catalytic process for the radical polymerization of monomers. He received the prestigious Wolf Prize in Chemistry in 2011, the Dreyfus Prize in the Chemical Sciences in 2015, and the Grand Prix de la Fondation de la Maison de la Chimie, France in 2020. Education and career Matyjaszewski began studying chemistry at Lodz University of Technology in late 1960s and later graduated from the Petrochemical Un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Persistent Radical Effect
The persistent radical effect (PRE) in chemistry describes and explains the selective product formation found in certain free-radical cross-reactions. In these type of reactions, different radicals compete in secondary reactions. The so-called persistent (long-lived) radicals do not self-terminate and only react in cross-couplings. In this way, the cross-coupling products in the product distribution are more prominent. The effect was first described in 1936 by Bachmann & Wiselogle. They heated pentaphenylethane and observed that the main reaction product was the starting product (87%) with only 2% of tetraphenylethane formed. They concluded that the dissociation of pentaphenylethane into triphenylmethyl and diphenylmethyl radicals was reversible and that persistent triphenylmethyl did not self terminate and transient diphenylmethyl did to a certain extent. In 1964, Perkins performed a similar reaction with phenylazotriphenylmethane in benzene. Again, the dimerization product of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virgil Percec
Virgil Percec (born December 8, 1946) is a Romanian-American chemist and P. Roy Vagelos Chair and Professor of Chemistry at the University of Pennsylvania. Expert in organic, macromolecular and supramolecular chemistry including self-assembly, biological membrane mimics, complex chiral systems, and catalysis. Pioneered the fields of liquid crystals with complex architecture, supramolecular dendrimers, Janus dendrimers and glycodendrimers, organic Frank-Kasper phases and quasicrystals, supramolecular polymers, helical chirality, Ni-catalyzed cross-coupling and multiple living and self-interrupted polymerizations. Most of these concepts were inspired by Nature and biological principles. Life Early life Percec was born in December 1946 in Siret, Romania. His father, Traian, was a schoolteacher and painter; his mother was named Virginia. Virgil attended Eudoxiu Hurmuzachi High School in Rădăuți. Education Percec received his BS in Organic and Macromolecular Chemistry a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reversible-deactivation Radical Polymerization
Reversible deactivation radical polymerizations (RDRPs) are members of the class of reversible deactivation polymerizations which exhibit much of the character of living polymerizations, but cannot be categorized as such as they are not without chain transfer or chain termination reactions. Several different names have been used in literature, which are: *Living radical polymerization *Living free radical polymerization *Controlled/"living" radical polymerization *Controlled radical polymerization *Reversible deactivation radical polymerization Though the term "living" radical polymerization was used in early days, it has been discouraged by IUPAC, because radical polymerization cannot be a truly living process due to unavoidable termination reactions between two radicals. The commonly used term controlled radical polymerization is permitted, but reversible-deactivation radical polymerization or controlled reversible-deactivation radical polymerization (RDRP) is recommended. Histor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atom-transfer Radical-polymerization
Atom transfer radical polymerization (ATRP) is an example of a reversible-deactivation radical polymerization. Like its counterpart, ATRA, or atom transfer radical addition, ATRP is a means of forming a carbon-carbon bond with a transition metal catalyst. Polymerization from this method is called atom transfer radical addition polymerization (ATRAP). As the name implies, the atom transfer step is crucial in the reaction responsible for uniform polymer chain growth. ATRP (or transition metal-mediated living radical polymerization) was independently discovered by Mitsuo Sawamoto and by Krzysztof Matyjaszewski and Jin-Shan Wang in 1995. ::The following scheme presents a typical ATRP reaction: Overview of ATRP ATRP usually employs a transition metal complex as the catalyst with an alkyl halide as the initiator (R-X). Various transition metal complexes, namely those of Cu, Fe, Ru, Ni, and Os, have been employed as catalysts for ATRP. In an ATRP process, the dormant species is activat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
