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In organic chemistry, neighbouring group participation (NGP, also known as anchimeric assistance) has been defined by the International Union of Pure and Applied Chemistry (IUPAC) as the interaction of a reaction centre with a lone pair of electrons in an atom or the electrons present in a sigma or pi bond contained within the parent molecule but not conjugated with the reaction centre.
The representative examples would be high nucleophilicities of hydroperoxide (HO 2 −) and hydrazine (N 2 H 4). [3] The effect is now well established with numerous examples and became an important concept in mechanistic chemistry and biochemistry. [4] However, the origin of the effect is still controversial without a clear winner.
Radiofrequency ablation (RFA) is a method of removing aberrant tissue from within the body via minimally invasive procedures, it is used to cure a variety of cardiac arrhythmia such as supraventricular tachycardia, Wolff–Parkinson–White syndrome (WPW), ventricular tachycardia, and more recently as management of atrial fibrillation.
Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...
A good example of a substitution reaction is halogenation. When chlorine gas (Cl 2) is irradiated, some of the molecules are split into two chlorine radicals (Cl•), whose free electrons are strongly nucleophilic. One of them breaks a C–H covalent bond in CH 4 and grabs the hydrogen atom to form the electrically neutral HCl.
Retrosynthetic analysis is a technique for solving problems in the planning of organic syntheses. This is achieved by transforming a target molecule into simpler precursor structures regardless of any potential reactivity/interaction with reagents. Each precursor material is examined using the same method.
In organic chemistry, functionality is often used as a synonym for functional group. For example, a hydroxyl group can also be called a HO-function. [1] [2] Functionalisation means the introduction of functional groups, for example the functionalisation of a surface [3] (e.g. silanization for the specific modification of the adhesion of a surface)
The relative activity of a species i, denoted a i, is defined [4] [5] as: = where μ i is the (molar) chemical potential of the species i under the conditions of interest, μ o i is the (molar) chemical potential of that species under some defined set of standard conditions, R is the gas constant, T is the thermodynamic temperature and e is the exponential constant.