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Vinylidene Group
In chemistry, vinylidenes are compounds with the functional group C=CH2. An example is 1,1-dichloroethene (CCl2=CH2) commonly called ''vinylidene chloride''. It and vinylidene fluoride are precursors to commercially useful polymers. Monomers and polymers Vinylidene chloride and fluoride can be converted to linear polymers polyvinylidene chloride (PVDC) and polyvinylidene fluoride (PVDF). The polymerization reaction is: : ''n'' CH2=CX2 → (CH2−CX2)''n'' These vinylidene polymers are isomeric with those produced from vinylene monomers. Thus polyvinylene fluoride from vinylene fluoride (HFC=CHF). Vinylidene complexes Although vinylidenes are only transient species, they are found as ligands in organometallic chemistry. They typically arise by the protonation of metal acetylides or by the reaction of metal electrophiles with terminal alkynes. The complex chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium readily forms such complexes: :CpRu(PPh3)2Cl + RC2H + K ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry
Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during chemical reaction, reactions with other chemical substance, substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both Basic research, basic and Applied science, applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium
Chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium is the organoruthenium half-sandwich compound with formula RuCl(PPh3)2(C5H5). It as an air-stable orange crystalline solid that is used in a variety of organometallic synthetic and catalytic transformations. The compound has idealized Cs symmetry. It is soluble in chloroform, dichloromethane, and acetone. Preparation Chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium was first reported in 1969 when it was prepared by reacting dichlorotris(triphenylphosphine)ruthenium(II) with cyclopentadiene. : RuCl2(PPh3)3 + C5H6 → RuCl(PPh3)3(C5H5) + HCl It is prepared by heating a mixture of ruthenium(III) chloride, triphenylphosphine, and cyclopentadiene in ethanol. Reactions Chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium(II) undergoes a variety of reactions often by involving substitution of the chloride. With phenylacetylene it gives the phenyl vinylidene complex: : (C5H5)(PPh3)2RuCl + HC2Ph + NH4 F6 � ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinyl Group
In organic chemistry, a vinyl group (abbr. Vi; IUPAC name: ethenyl group) is a functional group with the formula . It is the ethylene (IUPAC name: ethene) molecule () with one fewer hydrogen atom. The name is also used for any compound containing that group, namely where R is any other group of atoms. An industrially important example is vinyl chloride, precursor to PVC, a plastic commonly known as ''vinyl''. Vinyl is one of the alkenyl functional groups. On a carbon skeleton, sp2-hybridized carbons or positions are often called vinylic. Allyls, acrylates and styrenics contain vinyl groups. (A styrenic crosslinker with two vinyl groups is called '' divinyl benzene''.) Vinyl polymers Vinyl groups can polymerize with the aid of a radical initiator or a catalyst, forming vinyl polymers. Vinyl polymers contain no vinyl groups. Instead they are saturated. The following table gives some examples of vinyl polymers. Synthesis and reactivity Vinyl derivatives are alke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylene Group
A methylene group is any part of a molecule that consists of two hydrogen atoms bound to a carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ... atom, which is connected to the remainder of the molecule by two single bonds. The group may be represented as or , where the '>' denotes the two bonds. This stands in contrast to a situation where the carbon atom is bound to the rest of the molecule by a double bond, which is preferably called a methylidene group, represented . Formerly the methylene name was used for both isomers. The name “ methylene bridge“ can be used for the single-bonded isomer, to emphatically exclude methylidene. The distinction is often important, because the double bond is chemically different from two single bonds. The methylene group should be d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinylene Group
In chemistry, vinylene (also or 1,2-ethenediyl) is a divalent functional group (a part of a molecule) with formula −CH=CH−; namely, two carbons, each connected to the other by a double bond, to an hydrogen atom by a single bond, and to the rest of the molecule by another single bond. This group can be viewed as a molecule of ethene (ethylene, H2C=CH2) with a hydrogen removed from each carbon; or a vinyl group −CH=CH2 with one hydrogen removed from the terminal carbon. It should not be confused with the vinylidene group =C=CH2 or >C=CH2. A vinylene unit attached to two distinct atoms other than hydrogen (namely R−CH=CH−R') is a source of cis-trans isomerism. The vinylene group is the repeating unit in polyacetylene and in polyenes. See also * Vinyl group, the monovalent group −CH=CH2 * Vinylidene group In chemistry, vinylidenes are compounds with the functional group C=CH2. An example is 1,1-dichloroethene (CCl2=CH2) commonly called ''vinylidene chloride''. It and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbene
In organic chemistry, a carbene is a molecule containing a neutral carbon atom with a Valence (chemistry), valence of two and two unshared valence electrons. The general formula is or where the R represents substituents or hydrogen atoms. The term "carbene" may also refer to the specific compound , also called methylene radical, methylene, the parent hydride from which all other carbene compounds are formally derived. There are two types of carbenes: singlet state, singlets or triplet state, triplets, depending upon their electronic structure. The different classes undergo different reactions. Most carbenes are extremely reactive and short-lived. A small number (the diHalogen, halocarbenes, carbon monoxide, and carbon monosulfide) can be isolated, and can stabilize as Coordination complex, metal ligands, but otherwise cannot be stored in bulk. A rare exception are the persistent carbenes, which have extensive application in modern organometallic chemistry. Generatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylidenecarbene
Methylidenecarbene (systematically named λ2-ethene and dihydrido-1κ2''H''-dicarbon(''C''—''C'')) is an organic compound with the chemical formula (also written [] or ). It is a metastability, metastable proton tautomer of acetylene, which only persists as an adduct. It is a colourless gas that phosphoresces in the far-infrared range. It is the simplest unsaturated carbene. Nomenclature The systematic names ''λ2-ethene'', and ''dihydrido-1κ2H-dicarbon(C—C)'', valid IUPAC names, are constructed according to the substitutive and additive nomenclatures, respectively. In appropriate contexts, methylidenecarbene can be viewed as ethene with two hydrogen atoms removed, or as ethane with four hydrogens removed; and as such, ''ethen-1-ylidene'' (or ''vinylidene'') or ''ethane-1-diylidene'', respectively, may be used as a context-specific systematic names, according to substitutive nomenclature. By default, these names pay no regard to the radicality of the methylidenecarbene m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valence (chemistry)
In chemistry, the valence (US spelling) or valency (British spelling) of an atom is a measure of its combining capacity with other atoms when it forms chemical compounds or molecules. Valence is generally understood to be the number of chemical bonds that each atom of a given chemical element typically forms. Double bonds are considered to be two bonds, triple bonds to be three, quadruple bonds to be four, quintuple bonds to be five and sextuple bonds to be six. In most compounds, the valence of hydrogen is 1, of oxygen is 2, of nitrogen is 3, and of carbon is 4. Valence is not to be confused with the related concepts of the coordination number, the oxidation state, or the number of valence electrons for a given atom. Description The valence is the combining capacity of an atom of a given element, determined by the number of hydrogen atoms that it combines with. In methane, carbon has a valence of 4; in ammonia, nitrogen has a valence of 3; in water, oxygen has a valence of 2; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylide
In chemistry, an acetylide is a compound that can be viewed as the result of replacing one or both hydrogen atoms of acetylene (ethyne) by metallic or other cations. Calcium carbide is an important industrial compound, which has long been used to produce acetylene for welding and illumination. It is also a major precursor to vinyl chloride. Other acetylides are reagents in organic synthesis. Nomenclature The term acetylide is used loosely. It apply to an acetylene , where R = H or a side chain that is usually organic. The nomenclature can be ambiguous with regards to the distinction between compounds of the type and . When both hydrogens of acetylene are replaced by metals, the compound can also be called carbide, e.g. calcium carbide , which is calcium acetylide. When only one hydrogen atom is replaced, the anion may be called hydrogen acetylide or the prefix ''mono''- may be attached to the metal, as in monosodium acetylide or sodium hydrogen acetylide, . An acetylide may b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Functional Group
In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest of the molecule's composition. This enables systematic prediction of chemical reactions and behavior of chemical compounds and the design of chemical synthesis. The Reactivity (chemistry), reactivity of a functional group can be modified by other functional groups nearby. Functional group interconversion can be used in retrosynthetic analysis to plan organic synthesis. A functional group is a group of atoms in a molecule with distinctive Chemical property, chemical properties, regardless of the other atoms in the molecule. The atoms in a functional group are linked to each other and to the rest of the molecule by covalent bonds. For repeating units of polymers, functional groups attach to their Chemical polarity, nonp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organometallic Chemistry
Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and selenium, as well. Aside from bonds to organyl fragments or molecules, bonds to 'inorganic' carbon, like carbon monoxide (Metal carbonyl, metal carbonyls), cyanide, or carbide, are generally considered to be organometallic as well. Some related compounds such as transition metal hydrides and metal phosphine complexes are often included in discussions of organometallic compounds, though strictly speaking, they are not necessarily organometallic. The related but distinct term "metalorganics, metalorganic compound" refers to metal-containing compounds lacking direct metal-carbon bonds but which contain organic ligands. Metal β-diketonates, alkoxides, dialkylamides, and metal p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
