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Thiol-yne Reaction
In organic chemistry, the thiol-yne reaction (also known as alkyne hydrothiolation) is an organic reaction between a thiol () and an alkyne (). The reaction product is an alkenyl sulfide (). The reaction was first reported in 1949 with thioacetic acid as reagent and rediscovered in 2009. It is used in click chemistry and in polymerization, especially with dendrimers. This addition reaction is typically facilitated by a radical initiator or UV irradiation and proceeds through a sulfanyl radical species. With monoaddition a mixture of (''E''/''Z'')-alkenes form. The mode of addition is anti-Markovnikov. The radical intermediate can engage in secondary reactions such as cyclisation. With diaddition the 1,2-disulfide or the 1,1- dithioacetal forms. Reported catalysts for radical additions are triethylborane, indium(III) bromide and AIBN. The reaction is also reported to be catalysed by cationic rhodium and iridium complexes, by thorium and uranium complexes, by rhodium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Chemistry
Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Study of structure determines their structural formula. Study of properties includes Physical property, physical and Chemical property, chemical properties, and evaluation of Reactivity (chemistry), chemical reactivity to understand their behavior. The study of organic reactions includes the organic synthesis, chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical (in silico) study. The range of chemicals studied chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azobisisobutyronitrile
Azobisisobutyronitrile (abbreviated AIBN) is an organic compound with the formula . This white powder is soluble in alcohols and common organic solvents but is insoluble in water. It is often used as a foamer in plastics and rubber and as a radical initiator. As an azo initiator, radicals resulting from AIBN have multiple benefits over common organic peroxides. For example, they do not have oxygenated byproducts or much yellow discoloration. Additionally, they do not cause too much grafting and therefore are often used when making adhesives, acrylic fibers, detergents, etc. Mechanism of decomposition In its most characteristic reaction, AIBN decomposes, eliminating a molecule of nitrogen gas to form two 2-cyanoprop-2-yl radicals: Because azobisisobutyronitrile readily gives off free radicals, it is often used as a radical initiator. This happens at temperatures above 40 °C, but in experiments is more commonly done at temperatures between 66 °C and 72 °C.Cla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Block Copolymer
In polymer chemistry, a copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained from the copolymerization of two monomer species are sometimes called ''bipolymers''. Those obtained from three and four monomers are called ''terpolymers'' and ''quaterpolymers'', respectively. Copolymers can be characterized by a variety of techniques such as Nuclear magnetic resonance spectroscopy, NMR spectroscopy and size-exclusion chromatography to determine the molecular size, weight, properties, and composition of the material. Commercial copolymers include acrylonitrile butadiene styrene (ABS), styrene/butadiene co-polymer (SBR), nitrile rubber, styrene-acrylonitrile, styrene-isoprene-styrene (SIS) and ethylene-vinyl acetate, all of which are formed by chain-growth polymerization. Another production mechanism is step-growth polymerization, which is used to produce the nylon-12/6/66 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star Polymer
In polymer science, star-shaped polymers are the simplest class of branched polymers with a general structure consisting of several (at least three) linear chains connected to a central core. The core, or the center, of the polymer can be an atom, molecule, or macromolecule; the chains, or "arms", consist of variable-length organic chains. Star-shaped polymers in which the arms are all equivalent in length and structure are considered homogeneous, and ones with variable lengths and structures are considered heterogeneous. Star-shaped polymers' unique shape and associated properties, such as their compact structure, high arm density, efficient synthetic routes, and unique rheological properties make them promising tools for use in drug delivery, other biomedical applications, thermoplastics, and nanoelectronicsDrew C. Forman; Florian Wieberger; Andre Gröschel; Axel H. E. Müller; Hans-Werner Schmidt; Christopher K. Ober; Comparison of star and linear ArF resists. Proc. SPIE 7 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Addition Polymerization
Chain-growth polymerization ( AE) or chain-growth polymerisation ( BE) is a polymerization technique where monomer molecules add onto the active site on a growing polymer chain one at a time. There are a limited number of these active sites at any moment during the polymerization which gives this method its key characteristics. Chain-growth polymerization involves 3 types of reactions : # Initiation: An active species I* is formed by some decomposition of an initiator molecule I # Propagation: The initiator fragment reacts with a monomer M to begin the conversion to the polymer; the center of activity is retained in the adduct. Monomers continue to add in the same way until polymers Pi* are formed with the degree of polymerization i # Termination: By some reaction generally involving two polymers containing active centers, the growth center is deactivated, resulting in dead polymer Introduction In 1953, Paul Flory first classified polymerization as " step-growth polymeriza ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer Chemistry
Polymer chemistry is a sub-discipline of chemistry that focuses on the structures, chemical synthesis, and chemical and physical properties of polymers and macromolecules. The principles and methods used within polymer chemistry are also applicable through a wide range of other chemistry sub-disciplines like organic chemistry, analytical chemistry, and physical chemistry. Many materials have polymeric structures, from fully inorganic metals and ceramics to DNA and other biological molecules. However, polymer chemistry is typically related to synthetic and organic compositions. Synthetic polymers are ubiquitous in commercial materials and products in everyday use, such as plastics, and rubbers, and are major components of composite materials. Polymer chemistry can also be included in the broader fields of polymer science or even nanotechnology, both of which can be described as encompassing polymer physics and polymer engineering.Hans-Heinrich Moretto, Manfred Schulz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphenyl Disulfide
Diphenyl disulfide is the chemical compound with the formula (C6H5S)2. This colorless crystalline material is often abbreviated Ph2S2. It is one of the more commonly encountered organic disulfides in organic synthesis. Minor contamination by thiophenol is responsible for the disagreeable odour associated with this compound. Preparation and structure Diphenyl disulfide is usually prepared by the oxidation of thiophenol: : 2 PhSH + iodine, I2 → Ph2S2 + 2 HI Hydrogen peroxide can also be used as the oxidant. Ph2S2 is rarely prepared in the laboratory because it is inexpensive, and the precursor has a disagreeable odour. Like most organic disulfides, the C–S–S–C core of Ph2S2 is non-planar with a dihedral angle approaching 85°. Reactions Ph2S2 is mainly used in organic synthesis as a source of the PhS substituent. A typical reaction entails the formation of PhS-substituted carbonyl compounds via the enolate: :RC(O)CHLiR' + Ph2S2 → RC(O)CH(SPh)R' + LiSPh Reduction Ph2S2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichinose Thiol-yne 1987
Ichinose (written: 市瀬 ''or'' 市ノ瀬 ''or'' 一之瀬 ''or'' 一ノ瀬 ''or'' 一の瀬) is a Japanese surname. Notable people with the surname include: *, Japanese voice actor *, Japanese voice actress *, Japanese war photographer Fictional characters *, a character in the manga series ''Rent-A-Girlfriend'' *, a character in the manga series ''Seiyu's Life!'' *, a character in the manga series ''Seraph of the End'' *, the protagonist of the anime series ''Gatchaman Crowds'' *, a character in the manga series '' Maison Ikkoku'' *, a character in the manga series ''Riddle Story of Devil'' *, a character in the light novel and anime series ''Classroom of the Elite'' *, a character in the TV series '' Kamen Rider Gotchard'' *, a character in the anime series ''Aikatsu!'' *, a character in the manga series '' Maison Ikkoku'' *, a character in the visual novel ''Clannad'' *, a character in the manga series '' Ore Monogatari'' *, a character in the video game ''Persona 5 Strikers'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold
Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal, a group 11 element, and one of the noble metals. It is one of the least reactivity (chemistry), reactive chemical elements, being the second-lowest in the reactivity series. It is solid under standard temperature and pressure, standard conditions. Gold often occurs in free elemental (native state (metallurgy), native state), as gold nugget, nuggets or grains, in rock (geology), rocks, vein (geology), veins, and alluvial deposits. It occurs in a solid solution series with the native element silver (as in electrum), naturally alloyed with other metals like copper and palladium, and mineral inclusions such as within pyrite. Less commonly, it occurs in minerals as gold compounds, often with tellurium (gold tellurides). Gold is resistant to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caesium Carbonate
Caesium carbonate or cesium carbonate is a chemical compound with the chemical formula . It is white crystalline solid. Caesium carbonate has a high solubility in polar solvents such as water, ethanol and DMF. Its solubility is higher in organic solvents compared to other carbonates like potassium carbonate and sodium carbonate, although it remains quite insoluble in other organic solvents such as toluene, ''p''-xylene, and chlorobenzene. This compound is used in organic synthesis as a base. It also appears to have applications in energy conversion. Preparation Caesium carbonate can be prepared by thermal decomposition of caesium oxalate. Upon heating, caesium oxalate is converted to caesium carbonate with emission of carbon monoxide. : It can also be synthesized by reacting caesium hydroxide with carbon dioxide. : Chemical reactions Caesium carbonate facilitates the ''N''-alkylation of compounds such as sulfonamides, amines, β-lactams, indoles, heterocyclic compou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium
Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium radioactive decay, radioactively decays, usually by emitting an alpha particle. The half-life of this decay varies between 159,200 and 4.5 billion years for different isotopes of uranium, isotopes, making them useful for dating the age of the Earth. The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99% of uranium on Earth) and uranium-235 (which has 143 neutrons). Uranium has the highest atomic weight of the primordial nuclide, primordially occurring elements. Its density is about 70% higher than that of lead and slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few Parts-per notation#Parts-per expressions, parts per million in soil, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
