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Kläui Ligand
The Kläui ligand is the anion −. The ligand, popularized by Wolfgang Kläui, binds metals and metalloids via a facial O3 donor set. Related tridentate and tripodal anionic ligands include trispyrazolylborates. : 160px, General structure of a metal center coordinated to a κ3-Kläui ligand. The ligand is derived from the cationic complex of trimethylphosphite 2+ via an Arbuzov reaction. Using other phosphites and other cyclopentadienyl ligands, a large variety of derivatives are possible. The parent acid H is highly soluble in water (270 g/100 mL). Its p''K''a is about 2. Many complexes have been described, including bis(chelate 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 ...) complexes of the type {M 3}2.html" ;"title="CH3O)2PO.html" ;"title="(C5H5)Co[(CH3O)2PO">(C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligand
In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs, often through Lewis bases. The nature of metal–ligand bonding can range from covalent to ionic. Furthermore, the metal–ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acidic "ligands". Metals and metalloids are bound to ligands in almost all circumstances, although gaseous "naked" metal ions can be generated in a high vacuum. Ligands in a complex dictate the reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection requires critical consideration in many practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environmental chemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolfgang Kläui
Wolfgang is a German male given name traditionally popular in Germany, Austria and Switzerland. The name is a combination of the Old High German words ''wolf The wolf (''Canis lupus''; : wolves), also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. More than thirty subspecies of ''Canis lupus'' have been recognized, and gray wolves, as popularly u ...'', meaning "wolf", and ''wikt:gang#Old High German, gang'', meaning "path", "journey", "travel". Besides the regular "wolf", the first element also occurs in Old High German as the combining form "-olf". The earliest reference of the name being used was in the 8th century. The name was also attested as "Vulfgang" in the Reichenauer Verbrüderungsbuch in the 9th century. The earliest recorded famous bearer of the name was a tenth-century Wolfgang of Regensburg , Saint Wolfgang of Regensburg. Due to the lack of conflict with the pagan reference in the name with Catholicism, it i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metalloid
A metalloid is a type of chemical element which has a preponderance of material property, properties in between, or that are a mixture of, those of metals and nonmetals. There is no standard definition of a metalloid and no complete agreement on which elements are metalloids. Despite the lack of specificity, the term remains in use in the literature of chemistry. The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Five elements are less frequently so classified: carbon, aluminium, selenium, polonium, and astatine. On a standard periodic table, all eleven elements are in a diagonal region of the p-block extending from boron at the upper left to astatine at lower right. Some periodic tables include a dividing line between metals and nonmetals, and the metalloids may be found close to this line. Typical metalloids have a metallic appearance, but they are brittle and only fair electrical conductor, conductors of electricity. Chemica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tripodal Ligand
Tripodal ligands are tri- and tetradentate ligands. They are popular in research in the areas of coordination chemistry and homogeneous catalysis. Because the ligands are polydentate, they do not readily dissociate from the metal centre. Many tripodal ligands have C3 symmetry. Coordination chemistry In their coordination complexes with an octahedral molecular geometry the tridentate tripod ligands occupy one face, leading to a fixed facial (or ''fac'') geometry. The tetradentate tripodal ligands occupy four contiguous sites, leaving two ''cis'' positions available on the octahedral metal center. When bound to four- and five-coordinate metal centres, these ligands impose C3 symmetry, which can lead to uncommon ligand field splitting patterns. Tripodal ligands are often able to coordinately saturate metal ions with lower coordination numbers. One tripodal ligand of commercial significance is nitrilotriacetate, N(CH2CO2−)3 because it is cheaply produced and has a high affinity f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trispyrazolylborate
In inorganic chemistry, the trispyrazolylborate ligand, abbreviated Tp−, is an anionic tridentate and tripodal ligand. Trispyrazolylborate refers specifically to the anion B(C3N2H3)3sup>−, but the term trispyrazolylborate refers to derivatives substituted at on the pyrazolyl rings. This family of compounds are sometimes called scorpionate ligands. Tp ligands As suggested by the resonance structures, the nitrogen centers that are not bonded to boron are basic. These centers bind to three adjacent sites of a metal such that the simple adducts have C3v symmetry. The facial bonding mode is reminiscent of cyclopentadienyl ligands, although the ligand field stabilization energy of Tp− is weaker as indicated by the fact that Fe(Tp)2 is a spin-crossover complex whereas ferrocene is low-spin. The Tp ligands are usually prepared from the reaction of pyrazole with potassium borohydride: :KBH4 + 3 C3H3N2H → K B(C3N2H3)3 + 3H2 Intermediates include the monopyrazolylborate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimethylphosphite
Trimethyl phosphite is an organophosphorus compound with the formula P(OCH3)3, often abbreviated P(OMe)3. It is a colorless liquid with a highly pungent odor. It is the simplest phosphite ester and finds used as a ligand in organometallic chemistry and as a reagent in organic synthesis. The molecule features a pyramidal phosphorus(III) center bound to three methoxy groups. Synthesis Trimethyl phosphite is in principle obtainable by methanolysis of phosphorus trichloride, say in the presence of a proton accepting base. This method suffers from numerous side reactions however. The use of sodium methoxide is superior: : Reactions Trimethyl phosphite is susceptible to oxidation to trimethyl phosphate: : It reacts with a catalytic amount of methyl iodide in the Arbuzov reaction to give dimethyl methylphosphonate: :P(OCH3)3 → CH3P(O)(OCH3)2 As a ligand, trimethyl phosphite has a smaller cone angle and better acceptor properties relative to trimethylphosphine. A representati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arbuzov Reaction
Arbuzov (masculine, russian: Арбузов) or Arbuzova (feminine, russian: Арбузовa) is a Russian surname, derived from the word арбуз (''arbooz'', meaning "watermelon"). It may refer to: * Aleksandr Arbuzov (1877–1968), Russian and Soviet chemist * Aleksei Arbuzov (1908–1986), Soviet playwright * Boris Arbuzov (1903–1991), Russian and Soviet chemist * Boris Arbuzov (b. 1938), Russian and Soviet physicist * Serhiy Arbuzov Serhiy Hennadiyovych Arbuzov ( uk, Сергій Геннадійович Арбузов, russian: Сергей Геннадьевич Арбузов, translit=Sergey Gennadyevich Arbuzov; born 24 March 1976) is a Ukrainian former banker and polit ... (b. 1976), former bank director and former Vice Prime Minister of Ukraine in 2014 {{surname, Arbuzov Russian-language surnames ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphite
The general structure of a phosphite ester showing the lone pairs on the P In organic chemistry, a phosphite ester or organophosphite usually refers to an organophosphorous compound with the formula P(OR)3. They can be considered as esters of an unobserved tautomer phosphorous acid, H3PO3, with the simplest example being trimethylphosphite, P(OCH3)3. Some phosphites can be considered esters of the dominant tautomer of phosphorous acid (HP(O)(OH)2). The simplest representative is dimethylphosphite with the formula HP(O)(OCH3)2. Both classes of phosphites are usually colorless liquids. Synthesis ;From PCl3 Phosphite esters are typically prepared by treating phosphorus trichloride with an alcohol. Depending on the synthetic details, this alcoholysis can give the diorganophosphites: :PCl3 + 3 C2H5OH → (C2H5O)2P(O)H + 2 HCl + C2H5Cl Alternatively, when the alcoholysis is conducted in the presence of proton acceptors, one obtains the C3-symmetric trialkoxy derivatives ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclopentadienyl
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Cyclopentadienyl can refer to *Cyclopentadienyl anion, or cyclopentadienide, **Cyclopentadienyl ligand *Cyclopentadienyl radical, • *Cyclopentadienyl cation, See also *Pentadienyl In organic chemistry, pentadienyl refers to the organic radical, anion, or cation with the formula , where ''z'' = 0, −1, +1, respectively. Organometallic chemistry In organometallic chemistry, the pentadienyl anion is a ligand, the acyclic ana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chelate
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] |
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