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Acids and bases. A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any species that has a filled orbital containing an electron pair which is not involved in ...
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]
Retrieved from "https://en.wikipedia.org/w/index.php?title=Lewis_adduct&oldid=700226336"This page was last edited on 17 January 2016, at 05:32 (UTC). (UTC).
ECW model. In chemistry, the ECW model is a semi-quantitative model that describes and predicts the strength of Lewis acid – Lewis base interactions. Many chemical reactions can be described as acid–base reactions, so models for such interactions are of potentially broad interest. The model initially assigned E and C parameters to each and ...
HSAB theory. HSAB is an acronym for "hard and soft (Lewis) acids and bases ". HSAB is widely used in chemistry for explaining the stability of compounds, reaction mechanisms and pathways. It assigns the terms 'hard' or 'soft', and 'acid' or 'base' to chemical species. 'Hard' applies to species which are small, have high charge states (the ...
[15] In Lewis theory an acid, A, and a base, B, form an adduct, AB, where the electron pair forms a dative covalent bond between A and B. This is shown when the adduct H 3 N−BF 3 forms from ammonia and boron trifluoride, a reaction that cannot occur in water because boron trifluoride reacts violently with water in a hydrolysis reaction. [16]
Since Lewis adducts are formed by dative bond between Lewis bases and Lewis acids, the orbital overlap between the Lewis base and σ*(Sb–X) orbital is the source of the acidity. According to Gabbaï et al., NBO analysis of the Sb(C 6 F 5) 3 P(O)Ph 3 adduct indicates a donor-acceptor interaction between lp(O) and σ*(Sb–C 6 F 5). [7] [8]
Non-nucleophilic. Weak. v. t. e. A frustrated Lewis pair (FLP) is a compound or mixture containing a Lewis acid and a Lewis base that, because of steric hindrance, cannot combine to form a classical adduct. [1] Many kinds of FLPs have been devised, and many simple substrates exhibit activation. [2][3] The discovery that some FLPs split H 2[4 ...