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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.
In chemistry, the mesomeric effect (or resonance effect) is a property of substituents or functional groups in a chemical compound.It is defined as the polarity produced in the molecule by the interaction of two pi bonds or between a pi bond and lone pair of electrons present on an adjacent atom. [1]
In Organic chemistry, the inductive effect in a molecule is a local change in the electron density due to electron-withdrawing or electron-donating groups elsewhere in the molecule, resulting in a permanent dipole in a bond. [1] It is present in a σ (sigma) bond, unlike the electromeric effect which is present in a π (pi) bond.
In 2011, Jordi Poater and Miquel Solà expanded the rule to open-shell spherical compounds, finding they were aromatic when they had 2n 2 + 2n + 1 π-electrons, with spin S = (n + 1/2) - corresponding to a half-filled last energy level with the same spin. For instance C 60 1– is also observed to be aromatic with a spin of 11/2. [16]
A nitrenium ion (also called: aminylium ion or imidonium ion (obsolete)) in organic chemistry is a reactive intermediate based on nitrogen with both an electron lone pair and a positive charge and with two substituents (R 2 N +). [1] [2] Nitrenium ions are isoelectronic with carbenes, and can exist in either a singlet or a triplet state.
The isoelectric point (pI, pH(I), IEP), is the pH at which a molecule carries no net electrical charge or is electrically neutral in the statistical mean. The standard nomenclature to represent the isoelectric point is pH(I). [1] However, pI is also used. [2] For brevity, this article uses pI.
The rate constant (k 1) for this reaction was determined to be 1.0 × 10 8 M −1 s −1, while the parallel reaction of OH with NH + 4 was found to be much slower. This rate was redetermined by using two-pulse radiolysis competition methods with benzoate and thiocyanate ions at pH 11.4. A value of k 1 = (9 + 1) × 10 7 M −1 s −1 was
Piperidine is an organic compound with the molecular formula (CH 2) 5 NH. This heterocyclic amine consists of a six-membered ring containing five methylene bridges (–CH 2 –) and one amine bridge (–NH–). It is a colorless liquid with an odor described as objectionable, typical of amines. [6]