Salts negatively charged nucleophile

Alkyl halides can be alkylated by ethers or ketones to give oxonium salts, if a very weak, negatively charged nucleophile is present to serve as a counterion and a Lewis... 

The inner salt (93) is able to react with both electrophiles (RI) and nucleophiles (RM) to give (92) and (94), respectively. Radical combination following single electron transfer from the nucleophile is believed to account for the thiophilic addition whereby the negatively charged nucleophile fails to react at the positively charged carbenium carbon. 

Negatively charged nucleophiles like "OH and SH are used as salts with LT, Na% or K counterions to balance charge. The identity of the cation is usually inconsequential, and therefore it is often omitted from the chemical equation. 

Finally, it is pertinent, in the present connection, to make a distinction between those displacements in which the transformation of reactants to products does not, at any stage, involve the removal of a proton and those which do, at some stage, require the transfer of a proton to a base. The first type is exemplified by reactions with negatively charged nucleophiles such as alkoxide ion, iodide ion or a mercaptide ion or by reactions with tertiary amines or phosphines, which react to form quaternary ammonium compounds or phos-phonium salts, respectively. When the nucleophile is a primary or secondary amine, the product amine, which will have an additional aromatic ring attached to the amine nitrogen, is almost invariably a weaker base than the reactant amine. Here, as will be shown in later discussion, the question of base catalysis, with its attendant complications, arises. 

Phthalimide with a of 8 3 can be quantitatively converted to its potassium salt with potassium hydroxide The potassium salt of phthalimide has a negatively charged nitrogen atom which acts as a nucleophile toward primary alkyl halides m a bimolecu lar nucleophilic substitution (Sn2) process... 

Scheme 3 shows the conceivable reaction sites of alkenylbismuthonium salts, alkynylbismuthonium salts, bismuth ylides, and bismuth imides in carbon-carbon and carbon-heteroatom bond forming reactions. In the initial step, nucleophiles (Nu) attack the positively charged bismuth(V) center, a-proton or (3-carbon (Scheme 3a, b) whereas electrophiles (El) attack the negatively charged a-carbon or a-nitrogen (Scheme 3c, d). Usually, the resulting bismuth(V) intermediates... 

The reduction in pH reduces the negative charge of the albumin and so increases its electrophilic character. Therefore, as amphetamine molecules are nucleophilic in nature, their binding should improve with decrease in pH. Part of this binding will will involve salt formation between the amphetamine and the albumin. Amphetamine is more likely to form salts in which it acts as the positive ion as the electrophilic nature of the albumin decreases with increase in pH. 

The phosphorus-stabilized carbanion is an ylide (pronounced ilL-id )—a molecule that bears no overall charge but has a negatively charged carbon atom bonded to a positively charged heteroatom. Phosphorus ylides are prepared from tri-phenylphosphine and alkyl halides in a two-step process. The first step is nucleophilic attack by triphenylphosphine on an unhindered (usually primary) alkyl halide. The product is an alkyltriphenylphosphonium salt. The phosphonium salt is treated with a strong base (usually butyllithium) to abstract a proton from the carbon atom bonded to phosphorus. 

Powerful inorganic acceptors like the halogens, certain transition metal complexes, and negatively charged counterions with negligible nucleophilic tendency like BFT, CIOT, PFg, AsFg, NOj, CH SO, etc. result in fully ionic phenazine compounds. The physical properties of phenazine salts with inorganic anions have not been extensively or systematically studied. We mention below materials whose structures have been determined. 

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