Lewis acid

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Le·wis ac·id

(lū'wis),
an acid that is an electron pair acceptor.

Le·wis acid

(lū'is as'id)
An acid that is an electron pair acceptor.

Lewis acid

A substance that accepts an electron pair from a base, forming a covalent bond with the base.

Lewis,

Gilbert N., U.S. chemist, 1875-1946.
Lewis acid - an acid that is an electron pair acceptor.
References in periodicals archive ?
In our present study, we have investigated the one-pot multicomponent reactions (MCRs) to prepare aminopyridine derivatives 1-20 using different Lewis acid catalysts such as Zn[Cl.sub.2], Al[Cl.sub.3], and Fe[Cl.sub.3] using a molar ratio of 1: 2: 3 (aromatic aldehydes: malononitrile: primary amines) where the desired products were obtained in moderate yields.
An excellent catalytic activity of 5.0 wt% Ni-HMETS-10 for the conversion of cellulose to LA was attributed to the synergistic effect of Lewis acid sites and unique hierarchical porous structures centered at 16 nm in ETS-10 in a [H.sub.2] atmosphere (Table 6, entry 6) [353].
It can be easily predicted that other Lewis acids that promote glycosylations using glycosyl fluorides will be found in the future based on the concept of fluorophilicity.
Then, optionally, a second activator component and/or Lewis acid and subsequently the metal complex were added, and the resulting mixture was allowed to stir for an additional 30 minutes.
It is known that aziridines are not reactive towards nucleophilic compounds unless the nitrogen has been quatemized, protonated or has formed a Lewis acid adduct.
Table 3 lists the computed complexation energies for the [X.sub.3]AlY[C.sub.4][H.sub.4] (X = H, F, Cl and Br; Y = O in furan, Y = NH in pyrrole, and Y = S in thiophen), donor-acceptor complexes and the charge transfer from Y[C.sub.4][H.sub.4] Lewis bases to Al[X.sub.3] Lewis acids ([Q.sub.t]).
Their frustrated pair comprised of the Lewis base tetramethylpiperidine or TMP and the Lewis acid tris(pentafluorophenyl)borane.
The 3-APB Lewis acid receptor endows the hydrogel with saccharide responsivity, and ATMA is included at the specified concentration because of its ability to modify the sugar response of the sensor and increase its selectivity for glucose over other saccharides possessing cis-1,2- or -1,3-diols, including the main potential interferent for phenylboronic acids, fructose.
A mix of oligomers, resembling coal tar pitch, is created by co-polymerisation of anthracene with benzyl alcohol in the presence of Lewis acids at temperatures of around 200 [degrees]C (Otani, 1986)
Optimization studies have revealed that the reaction rate is very dependent on the nature of the solvent, and the presence of Lewis acids. Results from these studies will be presented.
Offers filled and untilled formulated liquid amines, polyamides, anhyd-rides, and Lewis acids.

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