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Dithiocarbamate Fungicide
In organic chemistry, a dithiocarbamate is a functional group with the general formula and structure . It is the analog of a carbamate in which both oxygen atoms are replaced by sulfur atoms (when only 1 oxygen is replaced the result is thiocarbamate). A common example is sodium diethyldithiocarbamate. Dithiocarbamates and their derivatives are widely used in the vulcanization of rubber. Formation Many primary and secondary amines react with carbon disulfide and sodium hydroxide to form dithiocarbamate salts: :R2NH + CS2 + NaOH → R2NCS2−Na+ + H2O Ammonia reacts with CS2 similarly: :2 NH3 + CS2 → H2NCS2−NH4+ Dithiocarbamate salts are pale colored solids that are soluble in water and polar organic solvents. Reactions Dithiocarbamates are readily S-alkylated. Thus, methyl dimethyldithiocarbamate can be prepared by methylation of the dithiocarbamate: :(CH3)2NCS2Na + (CH3O)2SO2 → (CH3)2NC(S)SCH3 + Na H3OSO3 Oxidation of dithiocarbamates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dithiocarbamate
In organic chemistry, a dithiocarbamate is a functional group with the general formula and structure . It is the analog of a carbamate in which both oxygen atoms are replaced by sulfur atoms (when only 1 oxygen is replaced the result is thiocarbamate). A common example is sodium diethyldithiocarbamate. Dithiocarbamates and their derivatives are widely used in the vulcanization of rubber. Formation Many primary and secondary amines react with carbon disulfide and sodium hydroxide to form dithiocarbamate salts: :R2NH + CS2 + NaOH → R2NCS2−Na+ + H2O Ammonia reacts with CS2 similarly: :2 NH3 + CS2 → H2NCS2−NH4+ Dithiocarbamate salts are pale colored solids that are soluble in water and polar organic solvents. Reactions Dithiocarbamates are readily S-alkylated. Thus, methyl dimethyldithiocarbamate can be prepared by methylation of the dithiocarbamate: :(CH3)2NCS2Na + (CH3O)2SO2 → (CH3)2NC(S)SCH3 + Na H3OSO3 Oxidation of dithiocarbamates gives th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition Metal Dithiocarbamate Complexes
133px, Tris(dithiocarbamate) complexes have idealized D3 symmetry. Transition metal dithiocarbamate complexes are coordination complexes containing one or more dithiocarbamate ligand, which are typically abbreviated R2dtc−. Many complexes are known. Several homoleptic derivatives have the formula M(R2dtc)n where n = 2 and 3. Ligand characteristics Dithiocarbamates are anions. Because of the pi-donor properties of the amino substituent, the two sulfur centers show enhanced basicity. This situation is represented by the zwitterionic resonance structure that depicts a positive charge on N and negative charges on both sulfurs. This N to C pi-bonding results in partial double bond character. Consequently, barriers to rotational about this bond are elevated. Another consequence of their high basicity, dithiocarbamates often stabilize complexes in uncharacteristically high oxidation state (e.g., Fe(IV), Co(IV), Ni(III), Cu(III)). Dithiocarbamate salts are easily synthesized. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mancozeb
Mancozeb is a dithiocarbamate non-systemic agricultural fungicide with multi-site, protective action on contact. It is a combination of two other dithiocarbamates: maneb and zineb. The mixture controls many fungal diseases in a wide range of field crops, fruits, nuts, vegetables, and ornamentals. It is marketed as Penncozeb, Trimanoc, Vondozeb, Dithane, Manzeb, Nemispot, and Manzane. In Canada, a mixture of zoxamide and mancozeb was registered for control of the mildew named Gavel as early as 2008. Mechanism Mancozeb reacts with, and inactivates, the sulfhydryl groups of amino acids and enzymes within fungal cells, resulting in disruption of lipid metabolism, respiration, and production of adenosine triphosphate. Mancozeb is listed under FRAC code M:03 The "M:" refers to Chemicals with Multi-Site Activity. "M:" FRAC groups are defined as generally considered as a low risk group without any signs of resistance developing to the fungicides. Toxicology A major toxicological conc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zineb
Zineb is the chemical compound with the formula n. Structurally, it is classified as a coordination polymer and a dithiocarbamate complex. This pale yellow solid is used as fungicide. Production and applications It is produced by treating ethylene bis(dithiocarbamate) sodium salt, "nabam", with zinc sulfate. This procedure can be carried out by mixing nabam and zinc sulfate in a spray tank.Michael A. Kamrin, (1997) Pesticide Profiles: Toxicity, Environmental Impact, and Fate, CRC Press, Its uses include control of downy mildews, rusts, and redfire disease. In the US it was once registered as a "General Use Pesticide", however all registrations were voluntarily cancelled following an EPA special review. It continues to be used in many other countries. Structure Zineb is a polymeric complex of zinc with a dithiocarbamate. The polymer is composed of Zn(dithiocarbamate)2 subunits linked by an ethylene (-CH2CH2-) backbone. A reference compound is n(S2CNEt2)2sub>2, which features ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size.The elements are from different metal groups. See periodic table. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity ( electrowinning). Zinc is an essential trace element for humans, animals, plants and for microorganisms and is necessary for prenatal and postnatal development. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maneb
Maneb is a fungicide and a polymeric complex of manganese with the ethylene bis(dithiocarbamate) anionic ligand.Arno H. Reidies "Manganese Compounds" Ullmann's Encyclopedia of Chemical Technology 2007; Wiley-VCH, Weinheim. Applications It can be also used to create a toxin-based animal model of Parkinson's disease, usually in primates. Regulation It was included in a pesticide ban proposed by the Swedish Chemicals Agency and approved by the European Parliament on January 13, 2009. See also *Metam sodium - A related dithiocarbamate salt which is also used as a fungicide. *Zineb - ethylene bis(dithiocarbamate) with zinc instead of manganese. *Mancozeb Mancozeb is a dithiocarbamate non-systemic agricultural fungicide with multi-site, protective action on contact. It is a combination of two other dithiocarbamates: maneb and zineb. The mixture controls many fungal diseases in a wide range of field ... - A common fungicide containing Zineb and Maneb. References External links * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manganese
Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy uses, particularly in stainless steels. It improves strength, workability, and resistance to wear. Manganese oxide is used as an oxidising agent; as a rubber additive; and in glass making, fertilisers, and ceramics. Manganese sulfate can be used as a fungicide. Manganese is also an essential human dietary element, important in macronutrient metabolism, bone formation, and free radical defense systems. It is a critical component in dozens of proteins and enzymes. It is found mostly in the bones, but also the liver, kidneys, and brain. In the human brain, the manganese is bound to manganese metalloproteins, most notably glutamine synthetase in astrocytes. Manganese was first isolated in 1774. It is familiar in the laboratory in the form of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyolefin
A polyolefin is a type of polymer with the general formula (CH2CHR)n where R is an alkyl group. They are usually derived from a small set of simple olefins (alkenes). Dominant in a commercial sense are polyethylene and polypropylene. More specialized polyolefins include polyisobutylene and polymethylpentene. They are all colorless or white oils or solids. Many copolymers are known, such as polybutene, which derives from a mixture of different butene isomers. The name of each polyolefin indicates the olefin from which it is prepared; for example, polyethylene is derived from ethylene, and polymethylpentene is derived from 4-methyl-1-pentene. Polyolefins are not olefins themselves because the double bond of each olefin monomer is opened in order to form the polymer. Monomers having more than one double bond such as butadiene and isoprene yield polymers that contain double bonds ( polybutadiene and polyisoprene) and are usually not considered polyolefins. Polyolefins are the foundat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crosslink
In chemistry and biology a cross-link is a bond or a short sequence of bonds that links one polymer chain to another. These links may take the form of covalent bonds or ionic bonds and the polymers can be either synthetic polymers or natural polymers (such as proteins). In polymer chemistry "cross-linking" usually refers to the use of cross-links to promote a change in the polymers' physical properties. When "crosslinking" is used in the biological field, it refers to the use of a probe to link proteins together to check for protein–protein interactions, as well as other creative cross-linking methodologies. Although the term is used to refer to the "linking of polymer chains" for both sciences, the extent of crosslinking and specificities of the crosslinking agents vary greatly. As with all science, there are overlaps, and the following delineations are a starting point to understanding the subtleties. Polymer chemistry Crosslinking is the general term for the process of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
