|
Stannoxane
Stannoxane is a functional group in organotin chemistry with the connectivity SnIV-O-SnIV (IV indicates the oxidation state of tin). Aside from the oxide group, usually 3 or 4 other substituents are attached to tin. In aqueous or aquatic environments, most organotin compounds contain this group.Davies, Alwyn George. (2004) Organotin Chemistry, 2nd Edition Weinheim: Wiley-VCH. : Synthesis and formation Stannoxanes form upon hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis i ... of organotin halides. For example, hydrolysis of dibutyltin dichloride gives the tetratin compound { u2ClSnsub>2O}2. The hydrolysis appears to proceed via organotin hydroxides. For example, the commercially important (C6H11)3SnOH converts at 200 °C into the distannoxane: :2 (C6H11)3SnOH → ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organotin Chemistry
Organotin compounds or stannanes are chemical compounds based on tin with hydrocarbon substituents. Organotin chemistry is part of the wider field of organometallic chemistry. The first organotin compound was diethyltin diiodide (), discovered by Edward Frankland in 1849. The area grew rapidly in the 1900s, especially after the discovery of the Grignard reagents, which are useful for producing Sn–C bonds. The area remains rich with many applications in industry and continuing activity in the research laboratory. Structure Organotin compounds are generally classified according to their oxidation states. Tin(IV) compounds are much more common and more useful. Organic derivatives of tin(IV) The tetraorgano derivatives are invariably tetrahedral. Compounds of the type SnRR'R''R have been resolved into individual enantiomers. Organotin halides Organotin chlorides have the formula for values of ''n'' up to 3. Bromides, iodides, and fluorides are also known but less important. Thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organotin Compounds
Organotin compounds or stannanes are chemical compounds based on tin with hydrocarbon substituents. Organotin chemistry is part of the wider field of organometallic chemistry. The first organotin compound was diethyltin diiodide (), discovered by Edward Frankland in 1849. The area grew rapidly in the 1900s, especially after the discovery of the Grignard reagents, which are useful for producing Sn–C bonds. The area remains rich with many applications in industry and continuing activity in the research laboratory. Structure Organotin compounds are generally classified according to their oxidation states. Tin(IV) compounds are much more common and more useful. Organic derivatives of tin(IV) The tetraorgano derivatives are invariably tetrahedral. Compounds of the type SnRR'R''R have been resolved into individual enantiomers. Organotin halides Organotin chlorides have the formula for values of ''n'' up to 3. Bromides, iodides, and fluorides are also known but less important. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Functional Group
In organic chemistry, a functional group is a substituent or 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 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 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 nonpolar core of carbon atoms and thus add chemical character to carbon chains. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidation State
In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state may be positive, negative or zero. While fully ionic bonds are not found in nature, many bonds exhibit strong ionicity, making oxidation state a useful predictor of charge. The oxidation state of an atom does not represent the "real" formal charge on that atom, or any other actual atomic property. This is particularly true of high oxidation states, where the ionization energy required to produce a multiply positive ion is far greater than the energies available in chemical reactions. Additionally, the oxidation states of atoms in a given compound may vary depending on the choice of electronegativity scale used in their calculation. Thus, the oxidation state of an atom in a compound is purely a formalism. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis is the cleavage of biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts. When a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g., sucrose being broken down into glucose and fructose), this is recognized as saccharification. Hydrolysis reactions can be the reverse of a condensation reaction in which two molecules join into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water. Types Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both the substance and water molecule to split into two parts. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Associative Mechanism
Associative substitution describes a pathway by which compounds interchange ligands. The terminology is typically applied to organometallic and coordination complexes, but resembles the Sn2 mechanism in organic chemistry. The opposite pathway is dissociative substitution, being analogous to the Sn1 pathway. Intermediate pathways exist between the pure associative and pure dissociative pathways, these are called interchange mechanisms. Associative pathways are characterized by binding of the attacking nucleophile to give a discrete, detectable intermediate followed by loss of another ligand. Complexes that undergo associative substitution are either coordinatively unsaturated or contain a ligand that can change its bonding to the metal, e.g. change in hapticity or bending of a nitrogen oxide ligand (NO). In homogeneous catalysis, the associative pathway is desirable because the binding event, and hence the selectivity of the reaction, depends not only on the nature of the m ... [...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 st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
