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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] |
Maneb
Maneb (manganese ethylene-bis-dithiocarbamate) is a fungicide and a polymeric complex of manganese with the ethylene bis (dithiocarbamate) anionic ligand. Health effects Exposure to maneb can occur when breathed in; it can irritate the eyes, nose, and throat as well as cause headache, fatigue, nervousness, dizziness, seizures and even unconsciousness. Prolonged or long-term exposure may interfere with the function of the thyroid. Exposure to maneb is also shown to induce a Parkinson's disease like neurotoxicity in mice. It is still challenged whether maneb, along with Paraquat, is an environmental risk factor for Parkinson's disease. Production Manganese(II) ethylenebis(dithiocarbamate) of low ethylenethiourea (ETU) content is prepared by mixing disodium ethylenebis (dithiocarbamate) with formaldehyde in aqueous medium then mixing a water-soluble manganese(II) salt to precipitate the maneb. The product can be further formulated with a metal salt and also with paraforma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metam Sodium
Metam sodium is an organosulfur compound with the formula . The compound is a sodium salt of a dithiocarbamate. The compound exists as a colorless dihydrate, but most commonly it is encountered as an aqueous solution. It is used as a soil fumigant, pesticide, herbicide, and fungicide. It is one of the most widely used pesticides in the United States, with approximately 60 million pounds used in 2001. Metam-sodium belongs to two HRAC groups, so it is designated Group A/C (Aus), Group A/C1 (global) and Group 1/5 (numeric). Preparation and properties Metam sodium is prepared by combining methylamine, carbon disulfide, and sodium hydroxide: : It also arises from the reaction of methyl isothiocyanate and sodium thiolate. Upon exposure to the environment, metam sodium decomposes to methyl isothiocyanate and other sulfur compounds. Safety and environmental considerations Metam sodium is nonpersistent in the environment since it decomposes rather quickly to toxic methyl isothio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc
Zinc is a chemical element; it has symbol Zn and atomic number 30. It 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. 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 is the second most abundant trace metal in humans after iron, an import ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dithiocarbamate Complex
image:Fe(Et2NCS2)3.svg, 193px, Structure of iron tris(diethyldithiocarbamate). 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 Dithiocarbamate anions are bidentate ligands that are classified as L-X ligand in the Covalent bond classification method. In the 18-electron rule, usual electron counting method, they are three-electron ligands. With respect to HSAB theory, they are classified as soft. Because of the pi-donor properties of the amino substituent, the two sulfur centers show enhanced basicity relative to dithiocarboxylates. 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 for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordination Polymer
Coordination may refer to: * Coordination (linguistics), a compound grammatical construction * Coordination complex, consisting of a central atom or ion and a surrounding array of bound molecules or ions ** A chemical reaction to form a coordination complex * Coordination number or ligancy of a central atom in a molecule or crystal is the number of atoms, molecules or ions bonded to it * Language coordination, the tendency of people to mimic the language of others * Coordination (political culture), a Utopian form of political regime * Motor coordination In physiology, motor coordination is the orchestrated movement of multiple body parts as required to accomplish intended actions, like walking. This coordination is achieved by adjusting kinematic and kinetic parameters associated with each bo ..., in animal motion * '' Gleichschaltung'' the process of Nazification in Germany after 1933, often translated as "coordination" See also * Coordinate (other) * Coordin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc Compounds
Zinc compounds are chemical compounds containing the element zinc which is a member of the group 12 element, group 12 of the periodic table. The oxidation state of zinc in most compounds is the group oxidation state of +2. Zinc may be classified as a post-transition main group element with zinc(II). Zinc compounds are noteworthy for their nondescript appearance and behavior: they are generally colorless (unlike compounds of other elements with oxidation number +2, which are colored), do not readily engage in redox reactions, and generally adopt symmetrical structures. General characteristics In its compounds, Zn2+ ions have an electronic configuration [Ar] 3d10. As such, Zn2+ tends to have a symmetrical coordination geometry in both its complexes and compounds. In both ZnO and ZnS, (zincblende) zinc is bound tetrahedrally bound to four ligands (oxide and sulfide, respectively). Many coordination complex, complexes, such as ZnCl42−, are tetrahedral. Tetrahedrally coordinated zin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocrine Disruptors
Endocrine disruptors, sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds are chemicals that can interfere with endocrine (or hormonal) systems. These disruptions can cause numerous adverse human health outcomes, including alterations in sperm quality and fertility; abnormalities in sex organs‚ endometriosis‚ early puberty‚ altered nervous system or immune function; certain cancers; respiratory problems; metabolic issues; diabetes, obesity, or cardiovascular problems; growth, neurological and learning disabilities, and more. Found in many household and industrial products, endocrine disruptors "interfere with the synthesis, secretion, transport, binding, action, or elimination of natural hormones in the body that are responsible for development, behavior, fertility, and maintenance of homeostasis (normal cell metabolism)." Any system in the body controlled by hormones can be derailed by hormone disrupto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungicides
Fungicides are pesticides used to kill parasitic fungi or their spores. Fungi can cause serious damage in agriculture, resulting in losses of yield and quality. Fungicides are used both in agriculture and to fight fungal infections in animals, including humans. Fungicides are also used to control oomycetes, which are not taxonomically/genetically fungi, although sharing similar methods of infecting plants. Fungicides can either be contact, translaminar or systemic. Contact fungicides are not taken up into the plant tissue and protect only the plant where the spray is deposited. Translaminar fungicides redistribute the fungicide from the upper, sprayed leaf surface to the lower, unsprayed surface. Systemic fungicides are taken up and redistributed through the xylem vessels. Few fungicides move to all parts of a plant. Some are locally systemic, and some move upward. Most fungicides that can be bought retail are sold in liquid form, the active ingredient being present at 0.08% i ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manganese
Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It 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 is commonly found in labo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dithiocarbamate
In organic chemistry, a dithiocarbamate is a chemical compound with the general formula . It contains the functional group with the Chemical structure, structure . It is the analog of a carbamate in which both oxygen atoms are replaced by sulfur atoms (when only one oxygen is replaced the result is thiocarbamate). Dithiocarbamate also refers to the dithiocarbamate ion and its salts. A common example is sodium diethyldithiocarbamate . Dithiocarbamates and their derivatives are widely used in the vulcanization of rubber. Formation Many secondary amines react with carbon disulfide and sodium hydroxide to form dithiocarbamate salts: : Ammonia reacts with carbon disulfide, similarly, to give ammonium dithiocarbamate: : Dithiocarbamate salts are pale colored solids that are soluble in water and Solvent, polar organic solvents. Dithiocarbamic acid A primary amine and carbon disulfide react to give a dithiocarbamic acid: : In the presence of diimides or pyridine, these acids convert t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridging Ligand
In coordination chemistry, a bridging ligand is a ligand that connects two or more atoms, usually metal ions. The ligand may be atomic or polyatomic. Virtually all complex organic compounds can serve as bridging ligands, so the term is usually restricted to small ligands such as pseudohalides or to ligands that are specifically designed to link two metals. In naming a complex wherein a single atom bridges two metals, the bridging ligand is preceded by the Greek letter mu, μ, with a subscript number denoting the number of metals bound to the bridging ligand. μ2 is often denoted simply as μ. When describing coordination complexes care should be taken not to confuse μ with η ('eta'), which relates to hapticity. Ligands that are not bridging are called terminal ligands. List of bridging ligands Virtually all ligands are known to bridge, with the exception of amines and ammonia. Common bridging ligands include most of the common anions. Many simple organic ligands form s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
