A study of metal ion catalysed hydrolysis

Abstract

It is now well known that metal ions catalyse many organic reactions in solution. These reactions include: the hydrolysis of carboxylic acid esters, amino acid esters, carboxylic acid amides, peptides, phosphate esters, and Schiff's bases; carboxylation and decarboxylation reactions; the hydrogenation and hydration of unsaturated systems; olefineforming elimination reactions; aldol condensations and nucleophilic displacement reactions. The subject of metal ion catalysis has been the subject of a number of reviews (1, 2, 3, 4) the latter being a recent contribution. Many organic compounds contain functional groups which are capable of forming chelate ring compounds with metal ions. The co-ordination of a metal ion to an organic substrate causes considerable shift of electron density and this may lead directly to catalytic effects. A metal co-ordinated to such a molecule, can act as an electron sink in the complex, can neutralise negative charge thus allowing the approach of a nucleophile, can cause polarisation of a particular bond in the substrate molecule or can stabilise a group leaving the molecule.