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Cyclopentadienylmolybdenumtricarbonyl Dimer
Cyclopentadienylmolybdenum tricarbonyl dimer is the chemical compound with the formula Cp2Mo2(CO)6, where Cp is C5H5. A dark red solid, it has been the subject of much research although it has no practical uses. Structure and synthesis The molecule exists in two rotamers, gauche and anti. The six CO ligands are terminal and the Mo-Mo bond distance is 3.2325 Å. The compound is prepared by treatment of molybdenum hexacarbonyl with sodium cyclopentadienide followed by oxidation of the resulting NaMo(CO)3(C5H5). Other methods have been developed starting with Mo(CO)3(CH3CN)3 instead of Mo(CO)6. Reactions Thermolysis of this compound in hot solution of diglyme Diglyme, or bis(2-methoxyethyl) ether, is a solvent with a high boiling point. It is an organic compound which is the dimethyl ether of diethylene glycol. (The name ''diglyme'' is a portmanteau of ''diglycol methyl ether''.) It is a colorless li ... (bis(2-methoxyethyl)ether) results in decarbonylation, giving the tetracarb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Debye
The debye (symbol: D) (; ) is a CGS unit (a non- SI metric unit) of electric dipole momentTwo equal and opposite charges separated by some distance constitute an electric dipole. This dipole possesses an electric dipole moment whose value is given as charge times length of separation, it is a vector whose direction is in the direction of the unit vector of the position vector of the positive charge w.r.t negative charge: :p = ''q''r. named in honour of the physicist Peter J. W. Debye. It is defined as statcoulomb-centimeters.The statcoulomb is also known as the franklin or electrostatic unit of charge. :1 statC = 1 Fr = 1 esu = 1 cm3/2⋅g1/2⋅s−1. Historically the debye was defined as the dipole moment resulting from two charges of opposite sign but an equal magnitude of 10−10 statcoulomb10−10 statcoulomb corresponds to approximately 0.2083 units of elementary charge. (generally called e.s.u. (electrostatic unit) in older scienti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diglyme
Diglyme, or bis(2-methoxyethyl) ether, is a solvent with a high boiling point. It is an organic compound which is the dimethyl ether of diethylene glycol. (The name ''diglyme'' is a portmanteau of ''diglycol methyl ether''.) It is a colorless liquid with a slight ether-like odor. It is miscible with water as well as organic solvents. It is prepared by a reaction of dimethyl ether and ethylene oxide over an acid catalyst. Solvent Because of its resistance to strong bases, diglyme is favored as a solvent for reactions of alkali metal reagents even at high temperatures. Rate enhancements in reactions involving organometallic reagents, such as Grignard reactions or metal hydride reductions, have been observed when using diglyme as a solvent. Diglyme is also used as a solvent in hydroboration reactions with diborane. It serves as a chelate for alkali metal cations, leaving anions more active Active may refer to: Music * ''Active'' (album), a 1992 album by Casiopea * A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Half Sandwich Compounds
One half ( : halves) is the irreducible fraction resulting from dividing one by two or the fraction resulting from dividing any number by its double. Multiplication by one half is equivalent to division by two, or "halving"; conversely, division by one half is equivalent to multiplication by two, or "doubling". One half often appears in mathematical equations, recipes, measurements, etc. Half can also be said to be one part of something divided into two equal parts. For instance, the area ''S'' of a triangle is computed. :''S'' = × perpendicular height. One half also figures in the formula for calculating figurate numbers, such as triangular numbers and pentagonal numbers: : \frac and in the formula for computing magic constants for magic squares : M_2(n) = \frac \left(n^ + 1\right) The Riemann hypothesis states that every nontrivial complex root of the Riemann zeta function has a real part equal to . One half has two different decimal expansion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimers (chemistry) , sometimes called dimerization
{{Disambiguation, surname ...
Dimer may refer to: * Dimer (chemistry), a chemical structure formed from two similar sub-units ** Protein dimer, a protein quaternary structure ** d-dimer * Dimer model, an item in statistical mechanics, based on ''domino tiling'' * Julius Dimer (1871–1945), German chess master See also * Dimery (botany), having two parts in a distinct whorl of a plant structure * Di (other), a prefix * Dymer (other) * -mer, a suffix * Oligomer * Peierls transition A Peierls transition or Peierls distortion is a distortion of the periodic lattice of a one-dimensional crystal. Atomic positions oscillate, so that the perfect order of the 1-D crystal is broken. Peierls’ theorem Peierls' theorem states that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonyl Complexes
In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups. A compound containing a carbonyl group is often referred to as a carbonyl compound. The term carbonyl can also refer to carbon monoxide as a ligand in an inorganic or organometallic complex (a metal carbonyl, e.g. nickel carbonyl). The remainder of this article concerns itself with the organic chemistry definition of carbonyl, where carbon and oxygen share a double bond. Carbonyl compounds In organic chemistry, a carbonyl group characterizes the following types of compounds: Other organic carbonyls are urea and the carbamates, the derivatives of acyl chlorides chloroformates and phosgene, carbonate esters, thioesters, lactones, lactams, hydroxamates, and isocyanates. Examples of inorganic carbonyl compounds are carbon dioxide and carbonyl sulfide. A s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organomolybdenum Compounds
Organomolybdenum chemistry is the chemistry of chemical compounds with Mo-C bonds. The heavier group 6 elements molybdenum and tungsten form organometallic compounds similar to those in organochromium chemistry but higher oxidation states tend to be more common. Mo(0) and more reduced states Molybdenum hexacarbonyl is the precursor to many substituted derivatives. It reacts with organolithium reagents to give anionic acyls which can be O-alkylated to give Fischer carbenes. 144px, Structure of (mesitylene)molybdenum tricarbonyl. Mo(CO)6 reacts with arenes to give piano-stool complexes such as (mesitylene)molybdenum tricarbonyl. Cycloheptatrienemolybdenum tricarbonyl, which is related to (arene)Mo(CO)3, reacts with trityl salts to give the cycloheptatrienyl complex: :(C7H8)Mo(CO)3 + (C6H5)3C+ → C7H7)Mo(CO)3sup>+ + (C6H5)3CH file:CHTMo(CO)3.png, 144px, Structure of Cycloheptatrienemolybdenum tricarbonyl. Reduction of Mo(CO)6 gives [Mo(CO)5]2− which is formally M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclopentadienylchromium Tricarbonyl Dimer
Cyclopentadienylchromium tricarbonyl dimer is the organochromium compound with the formula Cp2Cr2(CO)6, where Cp is C5H5. A dark green crystalline solid. It is the subject of research it exists in measureable equilibrium quantities with the monometallic radical CpCr(CO)3. Structure and synthesis The six CO ligands are terminal, and the Cr-Cr bond distance is 3.281 Å, 0.06 Å longer than the related dimolybdenum compound. The compound is prepared by treatment of chromium hexacarbonyl with sodium cyclopentadienide Sodium cyclopentadienide is an organosodium compound with the formula C5H5Na. The compound is often abbreviated as NaCp, where Cp− is the cyclopentadienide anion. Sodium cyclopentadienide is a colorless solid, although samples often are p ... followed by oxidation of the resulting NaCr(CO)3(C5H5). Related compounds * Cyclopentadienylmolybdenum tricarbonyl dimer * Cyclopentadienyltungsten tricarbonyl dimer References {{chromium compounds Organochromium c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclopentadienyltungsten Tricarbonyl Dimer
Cyclopentadienyltungsten tricarbonyl dimer is the organotungsten compound with the formula Cp2W2(CO)6, where Cp is C5H5. A dark red crystalline solid, it is the subject of research, although it has no or few practical uses. Structure and synthesis The molecule exists in two rotamers, gauche and anti. The six CO ligands are terminal, and the W-W bond distance is 3.222 Å. The compound is prepared by treatment of tungsten hexacarbonyl with sodium cyclopentadienide followed by oxidation of the resulting NaW(CO)3(C5H5). Related compounds * Cyclopentadienylmolybdenum tricarbonyl dimer * Cyclopentadienylchromium tricarbonyl dimer Cyclopentadienylchromium tricarbonyl dimer is the organochromium compound with the formula Cp2Cr2(CO)6, where Cp is C5H5. A dark green crystalline solid. It is the subject of research it exists in measureable equilibrium quantities with the mono ... References {{tungsten compounds Organotungsten compounds Carbonyl complexes Dimers (chemistry) Half ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Decomposition
Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition. If decomposition is sufficiently exothermic, a positive feedback loop is created producing thermal runaway and possibly an explosion or other chemical reaction. Decomposition temperature definition A simple substance (like water) may exist in equilibrium with its thermal decomposition products, effectively halting the decomposition. The equilibrium fraction of decomposed molecules increases with the temperature. Examples * Calcium carbonate (limestone or chalk) decomposes into calcium oxide and carbon dioxide when heated. The chemical reaction is as follows: ::CaCO3 → CaO + CO2 :The reaction is used to make quick lime, which is an industrially important product. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element is therefore not a compound. A compound can be transformed into a different substance by a chemical reaction, which may involve interactions with other substances. In this process, bonds between atoms may be broken and/or new bonds formed. There are four major types of compounds, distinguished by how the constituent atoms are bonded together. Molecular compounds are held together by covalent bonds; ionic compounds are held together by ionic bonds; intermetallic compounds are held together by metallic bonds; coordination complexes are held together by coordinate covalent bonds. Non-stoichiometric compounds form a disputed marginal case. A chemical formula specifies the number of atoms of each element in a compound molecule, using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inorganic Syntheses
''Inorganic Syntheses'' is a book series which aims to publish "detailed and foolproof" procedures for the synthesis of inorganic compounds. Although this series of books are edited, they usually are referenced like a journal, without mentioning the names of the checkers (referees) or the editor. A similar format is usually followed for the series ''''. Volumes See also *Organic Syntheses
''Organic Syntheses'' is a peer-reviewed scientific journal that was established in 1921. I ...
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Sodium Cyclopentadienide
Sodium cyclopentadienide is an organosodium compound with the formula C5H5Na. The compound is often abbreviated as NaCp, where Cp− is the cyclopentadienide anion. Sodium cyclopentadienide is a colorless solid, although samples often are pink owing to traces of oxidized impurities. Preparation Sodium cyclopentadienide is commercially available as a solution in THF. It is prepared by treating cyclopentadiene with sodium: : The conversion can be conducted by heating a suspension of molten sodium in dicyclopentadiene.Tarun K. Panda, Michael T. Gamer, Peter W. Roesky "An Improved Synthesis of Sodium and Potassium Cyclopentadienide" Organometallics, 2003, 22, 877–878. In former times, the sodium was provided in the form of "sodium wire" or "sodium sand", a fine dispersion of sodium prepared by melting sodium in refluxing xylene and rapidly stirring. Sodium hydride is a convenient base: : In early work, Grignard reagents were used as bases. With a p''K''a of 15, cyclope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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