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Dithietane
A dithietane is a saturated heterocyclic compound that contain two Valence (chemistry), divalent sulfur atoms and two Orbital hybridisation, sp3-hybridized carbon atoms. Two isomers are possible for this class of organosulfur compounds: 1,2-Dithietanes 1,2-dithietanes, 4-membered rings where the two sulfur atoms are adjacent, are very rare. The first stable 1,2-dithietane to be reported was the dithiatopazine, formed by intramolecular photodimerization of a dithiocarbonyl compound. 1,2-Dithietanes are to be distinguished from 1,2-dithietes, containing two adjacent sulfur atoms and two Orbital hybridisation, sp2-hybridized carbon centers. A stable 1,2-dithietane ''derivative'' is ''trans''-3,4-diethyl-1,2-dithietane 1,1-dioxide, formed by the spontaneous Dimer (chemistry), dimerization of the lachrymatory agent syn-propanethial-S-oxide, found in onion. 1,3-Dithietanes In 1,3-dithietanes, the sulfur atoms are non-adjacent. 1,3-Dithietane itself, a colorless, easily sublimed, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dithiete
Dithiete is an unsaturated heterocyclic compound that contains two adjacent sulfur atoms and two sp2-hybridized carbon centers. Derivatives are known collectively as dithietes or 1,2-dithietes. With 6 π electrons, 1,2-dithietes are examples of aromatic organosulfur compounds. A few 1,2-dithietes have been isolated; one (low-yielding) route is oxidation of a dithiolene complex. 3,4-Bis(trifluoromethyl)-1,2-dithiete is a particularly stable example. Unsubstituted 1,2-dithiete has been generated in thermolytic reactions and was characterized by microwave spectroscopy, ultraviolet photoelectron spectroscopy and infrared spectroscopy in a low temperature matrix. The open ring isomer, dithioglyoxal, HC(S)C(S)H, is less stable than the 1,2-dithiete. The dithione can be prepared (as ''trans''-dithioglyoxal) by low temperature photolysis of 1,3-dithiol-2-one. Quantum chemical calculations reproduce the observed greater stability of 1,2-dithiete only if large basis-sets with polariza ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocyclic Compound
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of organic heterocycles. Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass (cellulose and related materials), and many natural and synthetic dyes. More than half of known compounds are heterocycles. 59% of US FDA-approved drugs contain nitrogen heterocycles. Classification The study of organic heterocyclic chemistry focuses especially on organic unsaturated derivatives, and the preponderance of work and applications involves unstrained organic 5- and 6-membered rings. Included are pyridine, thiophene, pyrrole, and furan. Another large class of organic heterocycles refers to those fused to benzene rings. For example, the fused benzene derivatives of py ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Onion
An onion (''Allium cepa'' , from Latin ), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus '' Allium''. The shallot is a botanical variety of the onion which was classified as a separate species until 2011. The onion's close relatives include garlic, scallion, leek, and chives. The genus contains several other species variously called onions and cultivated for food, such as the Japanese bunching onion '' Allium fistulosum'', the tree onion ''Allium'' × ''proliferum'', and the Canada onion '' Allium canadense''. The name '' wild onion'' is applied to a number of ''Allium'' species, but ''A. cepa'' is exclusively known from cultivation. Its ancestral wild original form is not known, although escapes from cultivation have become established in some regions. The onion is most frequently a biennial or a perennial plant, but is usually treated as an annual and harvested in its first growing season. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfene
Sulfene is an extremely reactive chemical compound with the formula H2C=SO2. It is the simplest member of the sulfenes, the group of compounds which are ''S'',''S''-dioxides of thioaldehydes and thioketones, and have the general formula R2C=SO2. Preparation The first general method for preparation of sulfene as an intermediate, reported simultaneously in 1962 by Gilbert Stork and by Günther Optiz, involved the removal of hydrogen chloride from methanesulfonyl chloride using triethylamine in the presence of an enamine as trapping agent. The formation of a thietane 1,1-dioxide derivative was taken as evidence for the intermediacy of sulfene. Because of the highly electrophilic character of sulfene, the use of amines presents difficulties, since they can intercept the sulfene to form adducts. A simple alternative which avoids the use of amines involves desilylation of trimethylsilylmethanesulfonyl chloride with cesium fluoride in the presence of trapping agents. : (CH3)3SiCH2SO2C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synthesis Of 1,3-dithietane
Synthesis or synthesize may refer to: Science Chemistry and biochemistry *Chemical synthesis, the execution of chemical reactions to form a more complex molecule from chemical precursors **Organic synthesis, the chemical synthesis of organic compounds ***Total synthesis, the complete organic synthesis of complex organic compounds, usually without the aid of biological processes ***Convergent synthesis or linear synthesis, a strategy to improve the efficiency of multi-step chemical syntheses **Dehydration synthesis, a chemical synthesis resulting in the loss of a water molecule *Biosynthesis, the creation of an organic compound in a living organism, usually aided by enzymes **Photosynthesis, a biochemical reaction using a carbon molecule to produce an organic molecule, using sunlight as a catalyst **Chemosynthesis, the synthesis of biological compounds into organic waste, using methane or an oxidized molecule as a catalyst **Amino acid synthesis, the synthesis of an amino acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiophosgene
Thiophosgene is a red liquid with the formula . It is a molecule with trigonal planar geometry. There are two reactive C–Cl bonds that allow it to be used in diverse organic syntheses. Preparation Typically, is prepared in a two-step process from carbon disulfide. In the first step, carbon disulfide is chlorinated to give trichloromethanesulfenyl chloride (), a rare sulfenyl chloride: : The chlorination must be controlled as excess chlorine converts trichloromethanesulfenyl chloride into carbon tetrachloride. Steam distillation separates the trichloromethanesulfenyl chloride and hydrolyzes the disulfur dichloride. Reduction of trichloromethanesulfenyl chloride with, e.g., tin or dihydroanthracene produces thiophosgene: : An alternative one-step reaction is :CCl4 + H2S → SCCl2 + 2 HCl Reactions is mainly used to prepare compounds with the connectivity where X = OR, NHR. Such reactions proceed via intermediate such as CSClX. Under certain conditions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photochemically
Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400 nm), visible (400–750 nm), or infrared radiation (750–2500 nm). In nature, photochemistry is of immense importance as it is the basis of photosynthesis, vision, and the formation of vitamin D with sunlight. It is also responsible for the appearance of DNA mutations leading to skin cancers. Photochemical reactions proceed differently than temperature-driven reactions. Photochemical paths access high-energy intermediates that cannot be generated thermally, thereby overcoming large activation barriers in a short period of time, and allowing reactions otherwise inaccessible by thermal processes. Photochemistry can also be destructive, as illustrated by the photodegradation of plastics. Concept Grotthuss–Draper law and Stark–Einstein law Photoexci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borane
Borane is an inorganic compound with the chemical formula . Because it tends to dimerize or form adducts, borane is very rarely observed. It normally dimerizes to diborane in the absence of other chemicals. It can be observed directly as a continuously produced, transitory, product in a flow system or from the reaction of laser ablated atomic boron with hydrogen. Structure and properties BH3 is a trigonal planar molecule with D3h symmetry. The experimentally determined B–H bond length is 119 pm. In the absence of other bases, it dimerizes to form diborane. Thus, it is an intermediate in the preparation of diborane according to the reaction: :BX3 +BH4− → HBX3− + (BH3) (X=F, Cl, Br, I) :2 BH3 → B2H6 The standard enthalpy of dimerization of BH3 is estimated to be −170 kJ mol−1. The boron atom in BH3 has 6 valence electrons. Consequently, it is a strong Lewis acid and reacts with any Lewis base ('L' in equation below) to form an adduct: :BH3 + L � ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Sulfide
Sodium sulfide is a chemical compound with the formula Na2 S, or more commonly its hydrate Na2S·9 H2O. Both the anhydrous and the hydrated salts are colorless solids, although technical grades of sodium sulfide are generally yellow to brick red owing to the presence of polysulfides. It is commonly supplied as a crystalline mass, in flake form, or as a fused solid. They are water-soluble, giving strongly alkaline solutions. When exposed to moisture, Na2S immediately hydrates to give sodium hydrosulfide. Sodium sulfide has an unpleasant rotten egg smell due to the hydrolysis to hydrogen sulfide in moist air. Some commercial samples are described as Na2S·''x''H2O, where a weight percentage of Na2S is specified. Commonly available grades have around 60% Na2S by weight, which means that ''x'' is around 3. These grades of sodium sulfide are often marketed as 'sodium sulfide flakes'. These samples consist of NaSH, NaOH, and water. Structure The structures of sodium sulfides have bee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
