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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]
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 ...
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 ...
In chemistry, phosphine-boranes are organophosphorus compounds with the formula R 3−n H n PBH 3. They are Lewis acid-Lewis base adducts derived from organophosphines (PR 3−n H n) and borane (BH 3 ). They are generally colorless or white solids. Since these adducts are air-stable, they represent a protected form of the parent organophosphine.
TaCp 2 H 3 can form Lewis acid-base adducts with AlEt 3, GaEt 3, ZnEt 2, and CdEt 2 at the unique hydride. [10] As opposed to promotion of catalysis of olefin reactions with Lewis acids like AlEt 3 such as in Ziegler-Natta catalysts , triethylaluminium seems to deactivate the hydride ligand toward ethylene insertion.
Chemists like Ashe were able to utilize this knowledge in the 1990s to functionalize borepins as a compound, leading to the formation of many Lewis acid-base adducts. The most common borepin precursor used by chemists is a borepin-halide complex as halides are a good leaving group .
A 49-year-old Florida man hired and paid a man and a woman to travel to New Jersey to carry out an acid attack on a woman with whom he had had a prior relationship, authorities said.