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Diiodoacetylene
Diiodoacetylene is the organoiodine compound with the formula C2I2. It is a white, volatile solid that dissolves in organic solvents. It is prepared by iodination of trimethylsilylacetylene. Although samples explode above 80 °C, diiodoacetylene is the most readily handled of the dihaloacetylenes. Dichloroacetylene, for example, is more volatile and more explosive. As confirmed by X-ray crystallography, diiodoacetylene is linear. It is however a shock, heat and friction sensitive compound. Like other haloalkynes, diiodoacetylene is a strong halogen bond donor.{{cite journal , last1 = Cavallo , first1 = G. , last2 = Metrangolo , first2 = P. , last3 = Milani , first3 = R. , last4 = Pilati , first4 = T. , last5 = Priimagi , first5 = A. , last6 = Resnati , first6 = G. , last7 = Terraneo , first7 = G. , title = The Halogen Bond , journal= Chemical Reviews, Chem. Rev. , date = 2016 , volume = 116 , issue = 4 , pages = 2478–2601 , doi = 10.1021/acs.chemrev.5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimethylsilylacetylene
Trimethylsilylacetylene is the organosilicon compound with the formula . A colorless liquid, "tms acetylene", as it is also called, is used as a source of "HC2−" in organic synthesis. Use Trimethylsilylacetylene is used in Sonogashira couplings as the equivalent of acetylene. Using this protected alkyne, as opposed to acetylene itself, prevents further coupling reactions. The trimethylsilyl group can then be cleaved off with TBAF or DBU, either separately or as part of a one-pot Sonogashira reaction to form phenylacetylene derivatives. A less expensive alternative reagent is 2-methylbut-3-yn-2-ol, which after alkynylation is deprotected with base. Trimethylsilylacetylene is commercially available. It may also be prepared in a manner similar to other silyl compounds: deprotonation of acetylene with a Grignard reagent, followed by reaction with trimethylsilyl chloride. Trimethylsilylacetylene is a precursor to 1,4-bis(trimethylsilyl)buta-1,3-diyne, a protected form of 1,3-buta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichloroacetylene
Dichloroacetylene (DCA) is an organochlorine compound with the formula C2Cl2. It is a colorless, explosive liquid that has a sweet and "disagreeable" odor. Production Dichloroacetylene was first synthesized in 1930. Ether solutions of dichloroacetylene are relatively stable, and such solution can be safely generated by dehydrochlorination of trichlorethylene. A popular procedure use potassium hydride as the base: :Cl2C=CHCl + KH → ClC≡CCl + KCl + H2 A trace of methanol is required. It has also been generated (and used in situ) using lithium diisopropylamide under anhydrous conditions as well as potassium hydroxide. Dichloroacetylene is stabilized in the presence of ether, with which it forms an azeotrope (boiling point of 32 °C), and trichloroethylene. Adventitious routes It is a by-product in the production of vinylidene chloride. For instance, it can be formed from trichloroethylene. It is also possible to produce dichloroacetylene from trichloroethylene at low con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray Crystallography
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal. From this electron density, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds, their crystallographic disorder, and various other information. Since many materials can form crystals—such as salts, metals, minerals, semiconductors, as well as various inorganic, organic, and biological molecules—X-ray crystallography has been fundamental in the development of many scientific fields. In its first decades of use, this method determined the size of atoms, the lengths and types of chemical bonds, and the atomic-scale differences among various mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halogen Bond
A halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. Like a hydrogen bond, the result is not a formal chemical bond, but rather a strong electrostatic attraction. Mathematically, the interaction can be decomposed in two terms: one describing an electrostatic, orbital-mixing charge-transfer and another describing electron-cloud dispersion. Halogen bonds find application in supramolecular chemistry; drug design and biochemistry; crystal engineering and liquid crystals; and organic catalysis. Definition Halogen bonds occur when a halogen atom is electrostatically attracted to a partial negative charge. Necessarily, the atom must be covalently bonded in an antipodal σ-bond; the electron concentration associated with that bond leaves a positively charged "hole" on the other side. Although all halogens can t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Reviews
''Chemical Reviews'' is peer-reviewed scientific journal published twice per month by the American Chemical Society. It publishes review articles on all aspects of chemistry. It was established in 1924 by William Albert Noyes (University of Illinois). the editor-in-chief is Sharon Hammes-Schiffer. Abstracting and indexing The journal is abstracted and indexed in Chemical Abstracts Service, CAB International, EBSCOhost, ProQuest, PubMed, Scopus, and the Science Citation Index. According to the ''Journal Citation Reports'', the journal has a 2020 impact factor of 60.622. See also * Accounts of Chemical Research ''Accounts of Chemical Research'' is a semi-monthly peer-reviewed scientific journal published by the American Chemical Society containing overviews of basic research and applications in chemistry and biochemistry. It was established in 1968 and th ... References External links * American Chemical Society academic journals Review journals Monthly journals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inorganic Carbon Compounds
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''. Inorganic compounds comprise most of the Earth's crust, although the compositions of the deep mantle remain active areas of investigation. Some simple carbon compounds are often considered inorganic. Examples include the allotropes of carbon (graphite, diamond, buckminsterfullerene, etc.), carbon monoxide, carbon dioxide, carbides, and the following salts of inorganic anions: carbonates, cyanides, cyanates, and thiocyanates. Many of these are normal parts of mostly organic systems, including organisms; describing a chemical as inorganic does not necessarily mean that it does not occur within living things. History Friedrich Wöhler's conversion of ammonium cyanate into urea in 1828 is often cited as the starting point of modern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organoiodides
Organoiodine compounds are organic compounds that contain one or more carbon–iodine bonds. They occur widely in organic chemistry, but are relatively rare in nature. The thyroxine hormones are organoiodine compounds that are required for health and the reason for government-mandated iodization of salt. Structure, bonding, general properties Almost all organoiodine compounds feature iodide connected to one carbon center. These are usually classified as derivatives of I−. Some organoiodine compounds feature iodine in higher oxidation states. The C–I bond is the weakest of the carbon–halogen bonds. These bond strengths correlate with the electronegativity of the halogen, decreasing in the order F > Cl > Br > I. This periodic order also follows the atomic radius of halogens and the length of the carbon-halogen bond. For example, in the molecules represented by CH3X, where X is a halide, the carbon-X bonds have strengths, or bond dissociation energies, of 115, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
