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1,2-bis(diphenylphosphino)ethane
1,2-Bis(diphenylphosphino)ethane (dppe) is an organophosphorus compound with the formula (PhPCH) (Ph = phenyl). It is a commonly used bidentate ligand in coordination chemistry. It is a white solid that is soluble in organic solvents. Preparation The preparation of dppe is by the alkylation of NaPPh: :P(CH) + 2 Na → NaP(CH) + NaCH NaP(CH), which is readily air-oxidized, is treated with 1,2-dichloroethane (ClCHCHCl) to give dppe: :2 NaP(CH) + ClCHCHCl → (CH)PCHCHP(CH) + 2 NaCl Reactions The reduction of dppe by lithium to give PhHP(CH)PHPh has been reported. :PhP(CH)PPh + 4 Li → PhLiP(CH)PLiPh + 2 PhLi Hydrolysis gives the bis(secondary phosphine): :PhLiP(CH)PLiPh + 2 PhLi + 4HO → PhHP(CH)PHPh + 4 LiOH + 2 CH : Treatment of dppe with conventional oxidants such as hydrogen peroxide (HO), aqueous bromine (Br), etc., produces dppeO in low yield (e.g., 13%) as a result of non-selective oxidation.Encyclopedia of Reagents for Organic Synthesis 2001 John Wiley & Sons, Ltd Sel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organophosphorus Compound
Organophosphorus compounds are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective insecticides, although some are extremely toxic to humans, including sarin and VX nerve agents. Organophosphorus chemistry is the corresponding science of the properties and reactivity of organophosphorus compounds. Phosphorus, like nitrogen, is in group 15 of the periodic table, and thus phosphorus compounds and nitrogen compounds have many similar properties. The definition of organophosphorus compounds is variable, which can lead to confusion. In industrial and environmental chemistry, an organophosphorus compound need contain only an organic substituent, but need not have a direct phosphorus-carbon (P-C) bond. Thus a large proportion of pesticides (e.g., malathion), are often included in this class of compounds. Phosphorus can adopt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromine
Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table ( halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob Löwig (in 1825) and Antoine Jérôme Balard (in 1826), its name was derived from the Ancient Greek (bromos) meaning "stench", referring to its sharp and pungent smell. Elemental bromine is very reactive and thus does not occur as a native element in nature but it occurs in colourless soluble crystalline mineral halide salts, analogous to table salt. In fact, bromine and all the halogens are so reactive that they form bonds in pairs—never in single atoms. While it is rather rare in the Earth's crust, the high solubility of the bromide ion (Br) has caused its accumulation in the oceans. Comme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphosphines
Diphosphines, sometimes called bisphosphanes, are organophosphorus compounds most commonly used as bidentate phosphine ligands in inorganic and organometallic chemistry. They are identified by the presence of two phosphino groups linked by a backbone, and are usually chelating. A wide variety of diphosphines have been synthesized with different linkers and R-groups. Alteration of the linker and R-groups alters the electronic and steric properties of the ligands which can result in different coordination geometries and catalytic behavior in homogeneous catalysts. Synthesis 222px, Chlorodiisopropylphosphine is a popular building block for the preparation of diphosphines. From phosphide building blocks Many widely used diphosphine ligands have the general formula Ar2P(CH2)nPAr2. These compounds can be prepared from the reaction of X(CH2)nX (X=halogen) and MPPh2 (M = alkali metal): :Cl(CH2)nCl + 2 NaPPh2 → Ph2P(CH2)nPPh2 + 2 NaCl Diphosphine ligands can also be prepa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chelating Agents
Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are called chelants, chelators, chelating agents, or sequestering agents. They are usually organic compounds, but this is not a necessity, as in the case of zinc and its use as a maintenance therapy to prevent the absorption of copper in people with Wilson's disease. Chelation is useful in applications such as providing nutritional supplements, in chelation therapy to remove toxic metals from the body, as contrast agents in MRI scanning, in manufacturing using homogeneous catalysts, in chemical water treatment to assist in the removal of metals, and in fertilizers. Chelate effect The chelate effect is the greater affinity of chelating ligands for a metal ion than that of similar nonchelating (monodentate) ligands for the same met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bis(diphenylphosphino)methane
1,1-Bis(diphenylphosphino)methane (dppm), is an organophosphorus compound with the formula CH2(PPh2)2. Dppm, a white, crystalline powder, is used in inorganic and organometallic chemistry as a ligand. It is more specifically a chelating ligand because it is a ligand that can bond to metals with two phosphorus donor atoms. The natural bite angle is 73°. Synthesis and reactivity 1,1-Bis(diphenylphosphino)methane was first prepared by the reaction of sodium diphenylphosphide (Ph2PNa) with dichloromethane: :Ph3P + 2 Na → Ph2PNa + NaPh :2NaPPh2 + CH2Cl2 → Ph2PCH2PPh2 + 2 NaCl The methylene group (CH2) in dppm (and especially its complexes) is mildly acidic. The ligand can be oxidized to give the corresponding oxides and sulfides CH2 (E)Ph2sub>2 (E = O, S). The methylene group is even more acidic in these derivatives. Coordination chemistry As a chelating ligand, 1,1-bis(diphenylphosphino)methane forms a four-membered ring with the constituents MP2C. The ligand promotes the forma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,2-Bis(dimethylphosphino)ethane
1,2-Bis(dimethylphosphino)ethane (dmpe) is a diphosphine ligand in coordination chemistry. It is a colorless, air-sensitive liquid that is soluble in organic solvents. With the formula (CHPMe), dmpe is used as a compact strongly basic spectator ligand (Me = methyl), Representative complexes include V(dmpe)(BH), Mn(dmpe)(AlH), Tc(dmpe)(CO)Cl, and Ni(dmpe)Cl. Synthesis It is synthesised by the reaction of methylmagnesium iodide with 1,2-bis(dichlorophosphino)ethane: :ClPCHCHPCl + 4 MeMgI → MePCHCHPMe + 4 MgICl Alternatively it can be generated by alkylation of sodium dimethylphosphide. The synthesis of dmpe from thiophosphoryl chloride has led to serious accidents and has been abandoned.} Related ligands * Bis(dicyclohexylphosphino)ethane, a bulkier analogue, which is also a solid. * 1,2-Bis(diphenylphosphino)ethane 1,2-Bis(diphenylphosphino)ethane (dppe) is an organophosphorus compound with the formula (PhPCH) (Ph = phenyl). It is a commonly used bidentate li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bite Angle
In coordination chemistry the bite angle is the ligand–metal–ligand bond angle of coordination complex containing a bidentate ligand. This geometric parameter is used to classify chelating ligands, including those in organometallic complexes. It is most often discussed in terms of catalysis, as changes in bite angle can affect not just the activity and selectivity of a catalytic reaction but even allow alternative reaction pathways to become accessible. Although the parameter can be applied generally to any chelating ligand, it is commonly applied to describe diphosphine ligands, as they can adopt a wide range of bite angles. Diamines Diamines form a wide range of coordination complexes. They typically form 5- and 6-membered chelate rings. Examples of the former include ethylenediamine and 2,2′-bipyridine. Six-membered chelate rings are formed by 1,3-diaminopropane. The bite angle in such complexes is usually near 90°. Longer chain diamines, which are "floppy", tend not t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chelation
Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are called chelants, chelators, chelating agents, or sequestering agents. They are usually organic compounds, but this is not a necessity, as in the case of zinc and its use as a maintenance therapy to prevent the absorption of copper in people with Wilson's disease. Chelation is useful in applications such as providing nutritional supplements, in chelation therapy to remove toxic metals from the body, as contrast agents in MRI scanning, in manufacturing using homogeneous catalysts, in chemical water treatment to assist in the removal of metals, and in fertilizers. Chelate effect The chelate effect is the greater affinity of chelating ligands for a metal ion than that of similar nonchelating (monodentate) ligands for the same metal. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bis(dicyclohexylphosphino)ethane
Bis(dicyclohexylphosphino)ethane, abbreviated dcpe, is an organophosphorus compound with the formula (C6H11)2PCH2CH2P(C6H11)2. It is a white solid that is soluble in nonpolar organic solvents. The compound is used as a bulky and highly basic diphosphine ligand in coordination chemistry A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Man ....Sowa, J. R., Jr., Zanotti, V., Facchin, G., Angelici, R. J., "Calorimetric studies of the heats of protonation of the metal in Fe(CO)3(bidentate phosphine, arsine) complexes: effects of chelate ligands on metal basicity", J. Am. Chem. Soc. 1992, 114, 160. References {{DEFAULTSORT:Bis(dicyclohexylphosphino)ethane, 1,2- Chelating agents Diphosphines 1,2-Ethanediyl compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use, and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or " high-test peroxide", decomposes explosively when heated and has been used as a propellant in rocketry. Hydrogen peroxide is a reactive oxygen species and the simplest peroxide, a compound having an oxygen–oxygen single bond. It decomposes slowly when exposed to light, and rapidly in the presence of organic or reactive compounds. It is typically stored with a stabilizer in a weakly acidic solution in a dark bottle to block light. Hydrogen peroxide is found in biological systems including the human body. Enzymes that use or decompose hydrogen peroxide are classified as peroxidases. Properties The boiling p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenyl
In organic chemistry, the phenyl group, or phenyl ring, is a cyclic group of atoms with the formula C6 H5, and is often represented by the symbol Ph. Phenyl group is closely related to benzene and can be viewed as a benzene ring, minus a hydrogen, which may be replaced by some other element or compound to serve as a functional group. Phenyl group has six carbon atoms bonded together in a hexagonal planar ring, five of which are bonded to individual hydrogen atoms, with the remaining carbon bonded to a substituent. Phenyl groups are commonplace in organic chemistry. Although often depicted with alternating double and single bonds, phenyl group is chemically aromatic and has equal bond lengths between carbon atoms in the ring. Nomenclature Usually, a "phenyl group" is synonymous with C6H5− and is represented by the symbol Ph or, archaically, Φ. Benzene is sometimes denoted as PhH. Phenyl groups are generally attached to other atoms or groups. For example, triphenylmethane (Ph3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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