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Nitroxyl
Nitroxyl (common name) or azanone (IUPAC name) is the chemical compound HNO. It is well known in the gas phase. Nitroxyl can be formed as a short-lived intermediate in the solution phase. The conjugate base, NO−, nitroxide anion, is the redox reaction, reduced form of nitric oxide (NO) and is isoelectronic with dioxygen. The bond dissociation energy of H−NO is , which is unusually weak for a bond to the hydrogen atom. Generation Nitroxyl is produced from the reagents Angeli's salt (Na2N2O3) and Piloty's acid (PhSO2NHOH). Other notable studies on the production of HNO exploit cycloadducts of acyl nitroso species, which are known to decompose via hydrolysis to HNO and acyl acid. Upon photodissociation, photolysis these compounds release the acyl nitroso species which then further decompose. HNO is generated via organic oxidation of oxime, cyclohexanone oxime with lead tetraacetate to form 1-nitrosocyclohexyl acetate: : This compound can be hydrolyzed under base (chemistry), bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitroxyl Radical
Aminoxyl denotes a radical functional group with general structure R2N–O•. It is commonly known as a nitroxyl radical or a nitroxide, however IUPAC discourages the use of these terms, as they erroneously suggest the presence of a nitro group. Aminoxyls are structurally related to hydroxylamines and ''N''-oxoammonium salts, with which they can interconvert via a series of redox steps. Aminoxyl radical.svg, The general structure of the aminoxyl radical 2,2,6,6-Tetramethylpiperidinyloxyl.svg, TEMPO, a commonly encountered organic aminoxyl radical Kaliumnitrosodisulfonat.svg, Fremy's salt, an inorganic aminoxyl radical Sterically unhindered aminoxyls baring α-hydrogens are unstable and undergo rapid disproportionation to nitrones and hydroxylamines. Sterically hindered aminoxyls without α-hydrogens, such TEMPO and TEMPOL, and are persistent (stable) radicals and find use in a range of applications, both on the laboratory scale and in industry. Their ability to reversibly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfinamide
Sulfinamide is a functional group in organosulfur chemistry with the structural formula RS(O)NR'2 (where R and R' are organic substituents). This functionality is composed of a sulfur-carbon (S–C) and sulfur-nitrogen (S–N) single bonds, as well as a sulfur-oxygen double bond (S=O), resulting in a tetravalent sulfur centre (in resonance with its zwitterionic form). As a non-bonding electron pair is also present on the sulfur, these compounds are also chiral. They are sometimes referred to as ''S''-chiral sulfinamides. Sulfinamides are amides of sulfinic acid (RS(O)OH). Structure Sulfinamides do not undergo inversion. They can therefore be synthesised and/or isolated in enantiopure forms. This has led to their use as chiral ammonia equivalents and more broadly as chiral auxiliaries. Synthesis Sulfinamides are traditionally produced by the reaction of sulfinyl chlorides with primary or secondary amines. They also arise by the addition of Grignard reagents to sulfinylamines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angeli's Salt
Angeli's salt, sodium trioxodinitrate, is the inorganic compound with the formula Na2[N2O3]. It contains nitrogen in an unusual reduced state. It is a colorless, water-soluble solid, a salt. In research, this salt is used as a source of the metastable nitroxyl (HNO), which is a signalling molecule in nature. It is also known by the name sodium trioxodinitrate(II) monohydrate. Preparation and properties As first reported by Angelo Angeli in 1896, the salt is prepared by combining hydroxylamine and an organic nitrate, as a source of nitronium (): :NH2OH + RONO2 + 2 NaOR′ → ROH + 2 R′OH + Na2N2O3 The structure of the hydrate has been confirmed by X-ray crystallography. The anion is planar. Starting from the ONN end, the bond distances are 1.35 Å (N−O), 1.26 Å (N−N), 1.31 Å (N−O), and 1.32 Å (N−-O). The negative charge is on the oxygen atoms at opposite ends of the molecule. The angles are 112.9° (Osingle−N−N), 118.4° ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piloty's Acid
Piloty's acid is an organic compound with the formula C6H5SO2N(H)OH. A white solid, it is the benzenesulfonyl derivative of hydroxylamine. It is one of the main reagents used to generate nitroxyl (HNO), a highly reactive species that is implicated in a some chemical and biochemical reactions.{{cite journal, title=Synthesis, chemistry, and Applications of Nitroxyl Ion Releasers Sodium Trioxodinitrate or Angeli's Salt and Piloty's Acid, author1=Hughes, Martin N., author2=Cammack, Richard, journal=Methods in Enzymology (Nitric Oxide, Part C: Biological and Antioxidant Activities), year=1999, volume=301, pages=279–287, doi=10.1016/S0076-6879(99)01092-7 , pmid=9919577 See also * Angeli's salt Angeli's salt, sodium trioxodinitrate, is the inorganic compound with the formula Na2 2O3 It contains nitrogen in an unusual reduced state. It is a colorless, water-soluble solid, a salt. In research, this salt is used as a source of the metas ... References Hydroxylamines Sulfonamides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichloramine
Dichloramine is a reactive inorganic compound. It has the formula . The yellow gas is unstable and reacts with many materials. It is formed by a reaction between ammonia and chlorine or sodium hypochlorite. It is a byproduct formed during the synthesis of monochloramine and nitrogen trichloride. Synthesis Dichloramine can be prepared by a reaction between monochloramine and chlorine or sodium hypochlorite: :NH2Cl + Cl2 → NHCl2 + HCl Reaction Dichloramine reacts with hydroxyl ion, which can be present in water or comes from water molecules, to yield nitroxyl Nitroxyl (common name) or azanone (IUPAC name) is the chemical compound HNO. It is well known in the gas phase. Nitroxyl can be formed as a short-lived intermediate in the solution phase. The conjugate base, NO−, nitroxide anion, is the redox re ... radical and the chloride ion. References {{Nitrogen compounds Inorganic amines Inorganic chlorine compounds Chlorides Nitrogen halides Gases with color ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffusion-controlled Reaction
Diffusion-controlled (or diffusion-limited) reactions are reactions in which the reaction rate is equal to the rate of transport of the reactants through the reaction medium (usually a solution). The process of chemical reaction can be considered as involving the diffusion of reactants until they encounter each other in the right stoichiometry and form an activated complex which can form the product species. The observed rate of chemical reactions is, generally speaking, the rate of the slowest or "rate determining" step. In diffusion controlled reactions the formation of products from the activated complex is much faster than the diffusion of reactants and thus the rate is governed by collision frequency. Diffusion control is rare in the gas phase, where rates of diffusion of molecules are generally very high. Diffusion control is more likely in solution where diffusion of reactants is slower due to the greater number of collisions with solvent molecules. Reactions where the activ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloride Ion
The chloride ion is the anion (negatively charged ion) Cl−. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride salts such as sodium chloride are often very soluble in water.Green, John, and Sadru Damji. "Chapter 3." ''Chemistry''. Camberwell, Vic.: IBID, 2001. Print. It is an essential electrolyte located in all body fluids responsible for maintaining acid/base balance, transmitting nerve impulses and regulating liquid flow in and out of cells. Less frequently, the word ''chloride'' may also form part of the "common" name of chemical compounds in which one or more chlorine atoms are covalently bonded. For example, methyl chloride, with the standard name chloromethane (see IUPAC books) is an organic compound with a covalent C−Cl bond in which the chlorine is not an anion. Electronic properties A chloride ion (diameter 167 pm) is much larger than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weak Acid
Acid strength is the tendency of an acid, symbolised by the chemical formula HA, to dissociate into a hydron (chemistry), proton, H+, and an anion, A-. The Dissociation (chemistry), dissociation of a strong acid in solution is effectively complete, except in its most concentrated solutions. :HA -> H+ + A- Examples of strong acids are hydrochloric acid (HCl), perchloric acid (HClO4), nitric acid (HNO3) and sulfuric acid (H2SO4). A weak acid is only partially dissociated, with both the undissociated acid and its dissociation products being present, in solution, in Equilibrium chemistry, equilibrium with each other. :HA H+ + A- Acetic acid (CH3COOH) is an example of a weak acid. The strength of a weak acid is quantified by its acid dissociation constant, K_\ce value. The strength of a weak organic chemistry, organic acid may depend on substituent effects. The strength of an inorganic chemistry, inorganic acid is dependent on the oxidation state for the atom to which the prot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid Dissociation Constant
In chemistry, an acid dissociation constant (also known as acidity constant, or acid-ionization constant; denoted ) is a quantitative measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction :HA A^- + H^+ known as dissociation in the context of acid–base reactions. The chemical species HA is an acid that dissociates into , the conjugate base of the acid and a hydrogen ion, . The system is said to be in equilibrium when the concentrations of its components will not change over time, because both forward and backward reactions are occurring at the same rate. The dissociation constant is defined by :K_\text = \mathrm, or :\mathrmK_\ce = - \log_ K_\text = \log_\frac where quantities in square brackets represent the concentrations of the species at equilibrium. Theoretical background The acid dissociation constant for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the p''K''a v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spin-forbidden Reactions
In chemistry, the selection rule (also known as the transition rule) formally restricts certain reactions, known as spin-forbidden reactions, from occurring due to a required change between two differing quantum states. When a reactant exists in one spin state and the product exists in a different spin state, the corresponding reaction will have an increased activation energy when compared to a similar reaction in which the spin states of the reactant and product are isomorphic. As a result of this increased activation energy, a decreased rate of reaction is observed. Case of some cobalt carbonyls Singlet and triplet states can occur within organometallic complexes as well, such as Tp''i''-Pr,MeCo(CO)2 and Tp''i''-Pr,MeCo(CO), respectively. Changing spin states When a reaction converts a metal from a singlet to triplet state (or ''vice versa''): # The energy of the two spin states must be nearly equal, as dictated by temperature, # A mechanism is required to change spin stat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In Situ
''In situ'' (; often not italicized in English) is a Latin phrase that translates literally to "on site" or "in position." It can mean "locally", "on site", "on the premises", or "in place" to describe where an event takes place and is used in many different contexts. For example, in fields such as physics, geology, chemistry, or biology, ''in situ'' may describe the way a measurement is taken, that is, in the same place the phenomenon is occurring without isolating it from other systems or altering the original conditions of the test. The opposite of ''in situ'' is ''ex situ''. Aerospace In the aerospace industry, equipment on-board aircraft must be tested ''in situ'', or in place, to confirm everything functions properly as a system. Individually, each piece may work but interference from nearby equipment may create unanticipated problems. Special test equipment is available for this ''in situ'' testing. It can also refer to repairs made to the aircraft structure or flight con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrous Oxide
Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and has a slightly sweet scent and taste. At elevated temperatures, nitrous oxide is a powerful oxidiser similar to molecular oxygen. Nitrous oxide has significant medical uses, especially in surgery and dentistry, for its anaesthetic and pain-reducing effects. Its colloquial name, "laughing gas", coined by Humphry Davy, is due to the euphoric effects upon inhaling it, a property that has led to its recreational use as a dissociative anaesthetic. It is on the World Health Organization's List of Essential Medicines. It is also used as an oxidiser in rocket propellants, and in motor racing to increase the power output of engines. Nitrous oxide's atmospheric concentration reached 333 parts per billion (ppb) in 2020, increasing at a rate of abo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
