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In organic chemistry, an addition reaction is an organic reaction in which two or more molecules combine to form a larger molecule called the adduct. [1] [2] An addition reaction is limited to chemical compounds that have multiple bonds. Examples include a molecule with a carbon–carbon double bond (an alkene) or a triple bond (an alkyne).
In a Lewis adduct, the Lewis acid and base share an electron pair furnished by the Lewis base, forming a dative bond. [1] In the context of a specific chemical reaction between NH 3 and Me 3 B, a lone pair from NH 3 will form a dative bond with the empty orbital of Me 3 B to form an adduct NH 3 •BMe 3.
Because it is commonly recrystallized from chloroform, the complex is often supplied as the adduct [Pd 2 (dba) 3 ·CHCl 3]. [1] The purity of samples can be variable. [3] In [Pd 2 (dba) 3], the pair of Pd atoms are separated by 320 pm but are tied together by dba units. [4] The Pd(0) centres are bound to the alkene parts of the dba ligands.
A good example is the formation of adducts between the Lewis acid borane and the oxygen atom in the Lewis bases, tetrahydrofuran (THF): BH 3 ·O(CH 2) 4 or diethyl ether: BH 3 ·O(CH 3 CH 2) 2. Many Lewis acids and Lewis bases reacting in the gas phase or in non-aqueous solvents to form adducts have been examined in the ECW model. [3]
Adducts may arise as a consequence of the chemical reaction between a given "physicochemical agent to which an organism is exposed across the lifespan" (sometimes referred to as the exposome). These physicochemical agents can be exogenous in origin, and include ionizing and non-ionizing radiation, the diet, lifestyle factors, pollution, and ...
An alternative quantitative measure is the heat of formation of the Lewis acid-base adduct in a non-coordinating solvent. The ECW model is quantitative model that describes and predicts the strength of Lewis acid base interactions, -ΔH . The model assigned E and C parameters to many Lewis acids and bases.
In mass spectrometry, direct analysis in real time (DART) is an ion source that produces electronically or vibronically excited-state species from gases such as helium, argon, or nitrogen that ionize atmospheric molecules or dopant molecules.
[45] [46] This model also suggests that metal ion adducts (e.g., [M+Na] + or [M+K] +) are mainly generated from the thermally induced dissolution of salt. [47] The matrix-assisted ionization (MAI) method uses matrix preparation similar to MALDI but does not require laser ablation to produce analyte ions of volatile or nonvolatile compounds. [48]