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Bis(triphenylphosphine)platinum Chloride
Bis(triphenylphosphine)platinum chloride is a metal phosphine complex with the formula PtCl2 (C6H5)3sub>2. Cis- and trans isomers are known. The cis isomer is a white crystalline powder, while the trans isomer is yellow. Both isomers are square planar about the central platinum atom. The cis isomer is used primarily as a reagent for the synthesis of other platinum compounds. Preparation The cis isomer is the prepared by heating solutions of platinum(II) chlorides with triphenylphosphine. For example, starting from potassium tetrachloroplatinate: :K2PtCl4 + 2 PPh3 → ''cis''-Pt(PPh3)2Cl2 + 2 KCl The trans isomer is the prepared by treating potassium trichloro(ethylene)platinate(II) (Zeise's salt) with triphenylphosphine: :KPt(C2H4)Cl3 + 2 PPh3 → ''trans''-Pt(PPh3)2Cl2 + KCl + C2H4 With heating or in the presence of excess PPh3, the trans isomer converts to the cis complex. The latter complex is the thermodynamic product due to triphenylphosphine being a strong trans effect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal Phosphine Complex
A metal-phosphine complex is a In coordination complex containing one or more phosphine ligands. Almost always, the phosphine is an organophosphine of the type R3P (R = alkyl, aryl). Metal phosphine complexes are useful in homogeneous catalysis. Prominent examples of metal phosphine complexes include Wilkinson's catalyst (Rh(PPh3)3Cl), Grubbs' catalyst, and tetrakis(triphenylphosphine)palladium(0). Preparation Many metal phosphine complexes are prepared by reactions of metal halides with preformed phosphines. For example, treatment of a suspension of palladium chloride in ethanol with triphenylphosphine yields monomeric bis(triphenylphosphine)palladium(II) chloride units. :[PdCl2]n + 2PPh3 → PdCl2(PPh3)2 The first reported phosphine complexes were ''cis''- and ''trans''-PtCl2(PEt3)2 reported by Cahours and Gal in 1870. Often the phosphine serves both as a ligand and as a reductant. This property is illustrated by the synthesis of many platinum-metal complexes of triphenylphos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Square Planar
The square planar molecular geometry in chemistry describes the stereochemistry (spatial arrangement of atoms) that is adopted by certain chemical compounds. As the name suggests, molecules of this geometry have their atoms positioned at the corners. Examples Numerous compounds adopt this geometry, examples being especially numerous for transition metal complexes. The noble gas compound XeF4 adopts this structure as predicted by VSEPR theory. The geometry is prevalent for transition metal complexes with d8 configuration, which includes Rh(I), Ir(I), Pd(II), Pt(II), and Au(III). Notable examples include the anticancer drugs cisplatin tCl2(NH3)2and carboplatin. Many homogeneous catalysts are square planar in their resting state, such as Wilkinson's catalyst and Crabtree's catalyst. Other examples include Vaska's complex and Zeise's salt. Certain ligands (such as porphyrins) stabilize this geometry. Splitting of d-orbitals A general d-orbital splitting diagram for square planar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triphenylphosphine
Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to P Ph3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists as relatively air stable, colorless crystals at room temperature. It dissolves in non-polar organic solvents such as benzene and diethyl ether. Preparation and structure Triphenylphosphine can be prepared in the laboratory by treatment of phosphorus trichloride with phenylmagnesium bromide or phenyllithium. The industrial synthesis involves the reaction between phosphorus trichloride, chlorobenzene, and sodium: :PCl3 + 3 PhCl + 6 Na → PPh3 + 6 NaCl Triphenylphosphine crystallizes in triclinic and monoclinic modification. In both cases, the molecule adopts a pyramidal structure with propeller-like arrangement of the three phenyl groups. Principal reactions with chalcogens, halogens, and acids Oxidation Triphenylphosphine undergoes slow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Tetrachloroplatinate
Potassium tetrachloroplatinate(II) is the chemical compound with the formula K2PtCl4. This reddish orange salt is an important reagent for the preparation of other coordination complexes of platinum. It consists of potassium cations and the square planar dianion PtCl42−. Related salts are also known including Na2PtCl4, which is brown-colored and soluble in alcohols, and quaternary ammonium salts, which are soluble in a broader range of organic solvents. Preparation Potassium tetrachloroplatinate is prepared by reduction of the corresponding hexachloroplatinate salt with sulfur dioxide. K2PtCl4 is one of the salts that is most easily obtained from platinum ores. The complex is appreciably soluble only in water. Treatment with alcohols, especially in the presence of base, causes reduction to platinum metal. Organic tetrachloroplatinate salts, such as PPN.html" ;"title="/nowiki>PPN">/nowiki>PPN/nowiki>2PtCl4 are soluble in chlorocarbons. Reactions The chloride ligands on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeise's Salt
Zeise's salt, potassium trichloro(ethylene)platinate(II), is the chemical compound with the formula K platinum">PtCl3(C2H4).html" ;"title="platinum.html" ;"title="/nowiki>PtCl3(C2H4)">platinum.html"_;"title="/nowiki>platinum">PtCl3(C2H4)·H2O.__The_anion_of_this_air-stable,_yellow,_ PtCl3(C2H4)">platinum.html"_;"title="/nowiki>platinum">PtCl3(C2H4)·H2O.__The_anion_of_this_air-stable,_yellow,_Complex_(chemistry)">coordination_complex_contains_an_hapticity.html" ;"title="Complex_(chemistry).html" "title="platinum">PtCl3(C2H4)">platinum.html" ;"title="/nowiki>platinum">PtCl3(C2H4)·H2O. The anion of this air-stable, yellow, Complex (chemistry)">coordination complex contains an hapticity">''η''2-ethylene ligand. The anion features a platinum atom with a square planar geometry. The salt is of historical importance in the area of organometallic chemistry as one of the first examples of a transition metal alkene complex and is named for its discoverer, William Christopher Zeise. Prepa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trans Effect
In inorganic chemistry, the trans effect is the increased lability of ligands that are trans to certain other ligands, which can thus be regarded as trans-directing ligands. It is attributed to electronic effects and it is most notable in square planar complexes, although it can also be observed for octahedral complexes.Coe, B. J.; Glenwright, S. J. Trans-effects in octahedral transition metal complexes. ''Coordination Chemistry Reviews'' 2000, ''203'', 5-80. The analogous cis effect is most often observed in octahedral transition metal complexes. In addition to this ''kinetic trans effect'', trans ligands also have an influence on the ground state of the molecule, the most notable ones being bond lengths and stability. Some authors prefer the term trans influence to distinguish it from the kinetic effect, while others use more specific terms such as structural trans effect or thermodynamic trans effect. The discovery of the trans effect is attributed to Ilya Ilich Chernyaev, who ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoisomerization
In chemistry, photoisomerization is a form of isomerization induced by photoexcitation. Both reversible and irreversible photoisomerizations are known for photoswitchable compounds. The term "photoisomerization" usually, however, refers to a reversible process. Applications Photoisomerization of the compound retinal in the eye allows for vision. Photoisomerizable substrates have been put to practical use, for instance, in pigments for rewritable CDs, DVDs, and 3D optical data storage solutions. In addition, interest in photoisomerizable molecules has been aimed at molecular devices, such as molecular switches, molecular motors, and molecular electronics. Another class of device that uses the photoisomerization process is as an additive in liquid crystals to change their linear and nonlinear properties. Due to the photoisomerization is possible to induce a molecular reorientation in the liquid crystal bulk, which is used in holography, as spatial filter or optical switching. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bis(triphenylphosphine)palladium(II) Chloride
Bis(triphenylphosphine)palladium chloride is a coordination compound of palladium containing two triphenylphosphine and two chloride ligands. It is a yellow solid that is soluble in some organic solvents. It is used for palladium-catalyzed coupling reactions, e.g. the Sonogashira–Hagihara reaction. The complex is Square planar molecular geometry, square planar. Many analogous complexes are known with different phosphine ligands. Preparation and reactions This compound may be prepared by treating palladium(II) chloride with triphenylphosphine: :PdCl2 + 2 PPh3 → PdCl2(PPh3)2 Upon reduction with hydrazine in the presence of excess triphenylphosphine, the complex is a precursor to tetrakis(triphenylphosphine)palladium, Pd(PPh3)4: :2 PdCl2(PPh3)2 + 4 PPh3 + 5 N2H4 → 2 Pd(PPh3)4 + N2 + 4 N2H5+Cl− Structure Several crystal structures containing PdCl2(PPh3)2 have been reported. In all of the structures, PdCl2(PPh3)2 adopts a Square planar molecular geometry, square ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichlorobis(triphenylphosphine)nickel(II)
Dichlorobis(triphenylphosphine)nickel(II) refers to a pair of metal phosphine complexes with the formula NiCl2 (C6H5)3sub>2. The compound exists as two isomers, a paramagnetic dark blue solid and a diamagnetic red solid. These complexes function as catalysts for organic synthesis.Montgomery, J. Science of Synthesis Georg Thiene Verlag KG, Vol. 1, p 11, CODEN: SSCYJ9 Synthesis and structure The blue isomer is prepared by treating hydrated nickel chloride with triphenylphosphine in alcohols or glacial acetic acid: :NiCl2•6H2O + 2 PPh3 → NiCl2(PPh3)2 + 6 H2O When allowed to crystallise from chlorinated solvents, the tetrahedral isomer converts to the square planar isomer. The square planar form is red and diamagnetic. The phosphine ligands are trans with respective Ni-P and Ni-Cl distances of 2.24 and 2.17 Å. The blue form is paramagnetic and features tetrahedral Ni(II) centers. In this isomer, the Ni-P and Ni-Cl distances are elongated at 2.32 and 2.21 Å. As illustrated by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platinum(II) Compounds
Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish , a diminutive of "silver". Platinum is a member of the platinum group of elements and group 10 of the periodic table of elements. It has six naturally occurring isotopes. It is one of the rarer elements in Earth's crust, with an average abundance of approximately 5 μg/kg. It occurs in some nickel and copper ores along with some native deposits, mostly in South Africa, which accounts for ~80% of the world production. Because of its scarcity in Earth's crust, only a few hundred tonnes are produced annually, and given its important uses, it is highly valuable and is a major precious metal commodity. Platinum is one of the least reactive metals. It has remarkable resistance to corrosion, even at high temperatures, and is therefore considered a noble metal. Consequentl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homogeneous Catalysis
In chemistry, homogeneous catalysis is catalysis by a soluble catalyst in a solution. Homogeneous catalysis refers to reactions where the catalyst is in the same phase as the reactants, principally in solution. In contrast, heterogeneous catalysis describes processes where the catalysts and substrate are in distinct phases, typically solid-gas, respectively. The term is used almost exclusively to describe solutions and implies catalysis by organometallic compounds. Homogeneous catalysis is an established technology that continues to evolve. An illustrative major application is the production of acetic acid. Enzymes are examples of homogeneous catalysts. Examples Acid catalysis The proton is a pervasive homogeneous catalyst because water is the most common solvent. Water forms protons by the process of self-ionization of water. In an illustrative case, acids accelerate (catalyze) the hydrolysis of esters: :CH3CO2CH3 + H2O CH3CO2H + CH3OH At neutral pH, aqueous solutions of most e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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