|
Diaryliodonium Salts
Unlike its lighter congeners, the halogen iodine forms a number of stable organic compounds, in which iodine exhibits higher formal oxidation states than -1 or coordination number exceeding 1. These are the hypervalent organoiodines, often called iodanes after the IUPAC rule used to name them. These iodine compounds are hypervalent because the iodine atom formally contains in its valence shell more than the 8 electrons required for the octet rule. Hypervalent iodine oxyanions are known for oxidation states +1, +3, +5, and +7; organic analogues of these moieties are known for each oxidation state except +7. In terms of chemical behavior, λ3 and λ5iodanes are generally oxidizing and/or electrophilic species. They have been widely applied towards those ends in organic synthesis. Nomenclature Several different naming conventions are in use for the hypervalent organoiodines. All begin with nonstandard formal charge assignments. In iodane chemistry, carbon is c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congener (chemistry)
In chemistry, congeners are chemical substances "related to each other by origin, structure, or function". Common origin and structure Any significant quantity of a polyhalogenated compound is by default a blend of multiple molecule types because each molecule forms independently, and chlorine and bromine do not strongly select which site(s) they bond to. *Polychlorinated biphenyls (PCBs) are a family of 209 congeners. * Polybrominated biphenyls and polychlorinated diphenyl ethers are also families of 209 congeners. Similarly polychlorinated dibenzodioxins, polychlorinated dibenzofurans, polychlorinated terphenyls, polychlorinated naphthalene, polychloro phenoxy phenol, and polybrominated diphenyl ethers (PBDEs) ( pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether), etc. are also groups of congeners. Common origin *Congener (alcohol), substances other than alcohol (desirable or undesirable) also produced during fermentation. *Congeners of oleic acids ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iodoxybenzene
Periodinanes also known as λ5-iodanes are organoiodine compounds with iodine in the +5 oxidation state. These compounds are described as hypervalent because the iodine center has more than 8 valence electrons. Periodinane compounds The λ5-iodanes such as the Dess-Martin periodinane have square pyramidal geometry with 4 heteroatoms in basal positions and one apical phenyl group. Iodoxybenzene or iodylbenzene, , is a known oxidizing agent. Dess-Martin periodinane (1983) is another powerful oxidant and an improvement of the IBX acid already in existence in 1983. The IBX acid is prepared from 2-iodobenzoic acid and potassium bromate and sulfuric acid and is insoluble in most solvents whereas the Dess-Martin reagent prepared from reaction of the IBX acid with acetic anhydride is very soluble. The oxidation mechanism ordinarily consists of a ligand exchange reaction followed by a reductive elimination. Uses The predominant use of periodinanes is as oxidizing reagents replacing to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroform
Chloroform, or trichloromethane, is an organic compound with chemical formula, formula Carbon, CHydrogen, HChlorine, Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to PTFE. It is also a precursor to various refrigerants. It is trihalomethane. It is a powerful anesthetic, euphoriant, anxiolytic, and sedative when inhaled or ingested. Structure The molecule adopts a tetrahedral molecular geometry with C3v symmetry group, symmetry. Natural occurrence The total global flux of chloroform through the environment is approximately tonnes per year, and about 90% of emissions are natural in origin. Many kinds of seaweed produce chloroform, and fungi are believed to produce chloroform in soil. Abiotic processes are also believed to contribute to natural chloroform productions in soils although the mechanism is still unclear. Chloroform volatilizes readily from soil and surface water and undergoes degradation in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorine
Chlorine is a chemical element with the Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Electronegativity#Pauling electronegativity, Pauling scale, behind only oxygen and fluorine. Chlorine played an important role in the experiments conducted by medieval Alchemy, alchemists, which commonly involved the heating of chloride Salt (chemistry), salts like ammonium chloride (sal ammoniac) and sodium chloride (common salt), producing various chemical substances containing chlorine such as hydrogen chloride, mercury(II) chloride (corrosive sublimate), and hydrochloric acid (in the form of ). However ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iodobenzene Dichloride
Iodobenzene dichloride (PhICl2) is a complex of iodobenzene with chlorine. As a reagent for organic chemistry, it is used as an oxidant and chlorinating agent. Chemical structure Single-crystal X-ray crystallography has been used to determine its structure; as can be predicted by VSEPR theory, it adopts a T-shaped geometry about the central iodine atom. Preparation Iodobenzene dichloride is not stable and is not commonly available commercially. It is prepared by passing chlorine gas through a solution of iodobenzene in chloroform, from which it precipitates. The same reaction has been reported at pilot plant scale (20 kg) as well. :Ph-I + Cl2 → PhICl2 An alternate preparation involving the use of chlorine generated ''in situ'' by the action of sodium hypochlorite on hydrochloric acid has also been described. Reactions Iodobenzene dichloride is hydrolyzed by basic solutions to give iodosobenzene (PhIO) and is oxidized by sodium hypochlorite to give iodoxybenz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conrad Willgerodt
Conrad Heinrich Christoph Willgerodt (November 2, 1841 – December 19, 1930) was a German chemist who first described the Willgerodt reaction. Alongside the Willgerodt reaction, he had also discovered Iodosobenzene and chlorobutanol. As for his career, Conrad Willgerodt was a professor at the University of Freiburg The University of Freiburg (colloquially german: Uni Freiburg), officially the Albert Ludwig University of Freiburg (german: Albert-Ludwigs-Universität Freiburg), is a public university, public research university located in Freiburg im Breisg .... References External links * 1841 births 1930 deaths 19th-century German chemists University of Freiburg faculty People from Goslar (district) People from the Duchy of Brunswick 20th-century German chemists {{Germany-chemist-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organoiodine Chemistry
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 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3-center-4-electron Bond
The 3-center 4-electron (3c–4e) bond is a model used to explain bonding in certain hypervalent molecules such as tetratomic and hexatomic interhalogen compounds, sulfur tetrafluoride, the xenon fluorides, and the bifluoride ion. It is also known as the Pimentel–Rundle three-center model after the work published by George C. Pimentel in 1951,Pimentel, G. C. The Bonding of Trihalide and Bifluoride Ions by the Molecular Orbital Method. ''J. Chem. Phys.'' 1951, ''19'', 446-448. which built on concepts developed earlier by Robert E. Rundle for electron-deficient bonding.Rundle, R. E. Electron Deficient Compounds. II. Relative Energies of "Half-Bonds". ''J. Chem. Phys.'' 1949, ''17'', 671–675. An extended version of this model is used to describe the whole class of hypervalent molecules such as phosphorus pentafluoride and sulfur hexafluoride as well as multi-center π-bonding such as ozone and sulfur trioxide. There are also molecules such as diborane (B2H6) and dialane (Al2H6) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D-orbital
In atomic theory and quantum mechanics, an atomic orbital is a Function (mathematics), function describing the location and wave-like behavior of an electron in an atom. This function can be used to calculate the probability of finding any electron of an atom in any specific region around the Atomic nucleus, atom's nucleus. The term ''atomic orbital'' may also refer to the physical region or space where the electron can be calculated to be present, as predicted by the particular mathematical form of the orbital. Each orbital in an atom is characterized by a set of values of the three quantum numbers , , and , which respectively correspond to the electron's energy, angular momentum, and an angular momentum vector component (magnetic quantum number). Alternative to the magnetic quantum number, the orbitals are often labeled by the associated Spherical harmonics#Harmonic polynomial representation, harmonic polynomials (e.g., ''xy'', ). Each such orbital can be occupied by a maximum o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-type Ligand
X-type may refer to: * Jaguar X-Type, an entry-level luxury car that was manufactured and marketed by Jaguar Cars * X-type asteroid * LGOC X-type, an early model of London double-decker bus * X-type histiocytosis, a clinically well-defined group of cutaneous syndromes characterized by infiltrates of Langerhans cells See also * Type X {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenyl Group
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] |
Electron Counting
Electron counting is a formalism used for classifying compounds and for explaining or predicting electronic structure and bonding. Many rules in chemistry rely on electron-counting: *Octet rule is used with Lewis structures for main group elements, especially the lighter ones such as carbon, nitrogen, and oxygen, * 18-electron rule in inorganic chemistry and organometallic chemistry of transition metals, *Hückel's rule for the π-electrons of aromatic compounds, *Polyhedral skeletal electron pair theory for polyhedral cluster compounds, including transition metals and main group elements and mixtures thereof, such as boranes. Atoms are called " electron-deficient" when they have too few electrons as compared to their respective rules, or "hypervalent" when they have too many electrons. Since these compounds tend to be more reactive than compounds that obey their rule, electron counting is an important tool for identifying the reactivity of molecules. Counting rules Two m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
