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A hydroxide ion acting as a nucleophile in an S N 2 reaction, converting a haloalkane into an alcohol. In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they ...
Aprotic solvents do not add protons (H + ions) into solution; if protons were present in S N 2 reactions, they would react with the nucleophile and severely limit the reaction rate. Since this reaction occurs in one step, steric effects drive the reaction speed. In the intermediate step, the nucleophile is 185 degrees from the leaving group and ...
The international pictogram for oxidizing chemicals. Dangerous goods label for oxidizing agents. An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or "accepts"/"receives" an electron from a reducing agent (called the reductant, reducer, or electron donor).
For example, OH − is a better nucleophile than water, and I − is a better nucleophile than Br − (in polar protic solvents). In a polar aprotic solvent, nucleophilicity increases up a column of the periodic table as there is no hydrogen bonding between the solvent and nucleophile; in this case nucleophilicity mirrors basicity.
Organometallic compounds of electropositive metals are superbases, but they are generally strong nucleophiles. Examples include organolithium and organomagnesium ( Grignard reagent ) compounds. Another type of organometallic superbase has a reactive metal exchanged for a hydrogen on a heteroatom , such as oxygen (unstabilized alkoxides ) or ...
Ammonolysis refers to solvolysis by ammonia, but can also describe nucleophilic attack by ammonia more generally. Ammonia boils at −33 °C, and, as such, is rarely used as a solvent in its pure form. It is, however, readily miscible with water, and is commonly used in the form of a saturated aqueous solution. For this reason, ammonolysis may ...
In such reactions, the nucleophile is usually electrically neutral or negatively charged, whereas the substrate is typically neutral or positively charged. An example of nucleophilic substitution is the hydrolysis of an alkyl bromide, R−Br, under basic conditions, where the attacking nucleophile is the base OH − and the leaving group is Br −:
The following is the reaction mechanism of a nucleophilic aromatic substitution of 2,4-dinitrochlorobenzene (1) in a basic solution in water. Nucleophilic aromatic substitution Since the nitro group is an activator toward nucleophilic substitution, and a meta director, it is able to stabilize the additional electron density (via resonance) when ...