Development of metal-ion containing catalysts for the decomposition of phosphorothioate esters

• Published in: Biochimica et biophysica acta Vol. 1834; no. 1; pp. 433 - 442
• Main Authors: Edwards, David R., Brown, R. Stan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2013
• Subjects: Catalysis; Cations, Divalent - chemistry; Diester; Hydrolysis; Metals, Heavy - chemistry; Methanol - chemistry; Methanolysis; Models, Chemical; Organothiophosphates - chemistry; Phosphate; Phosphorothioate; Triester; Hydrolysis; Phosphorothioate; Triester; Methanolysis; Phosphate; Diester
• ISSN: 1570-9639; 0006-3002; 1878-1454
• DOI: 10.1016/j.bbapap.2012.02.006

The widespread use of phosphorothioate esters as agricultural pesticides, chemical weapons and mechanistic probes in enzymology has sparked interest in the reactivity of these thio-substituted analogues of phosphate esters. In this brief account, we summarize the recent developments in our understanding of the mechanisms of hydrolysis (and solvolysis in methanol) of phosphorothioates containing a sulfur atom in the bridging and/or non-bridging position. A small number of highly efficient catalytic systems containing the metal ions La(III), Pd(II), Cu(II) and Zn(II) have been developed to promote the degradation of the various classes of phosphorothioate esters. The mechanisms of the base promoted solvolytic reactions in water and methanol and those of the metal catalyzed cleavage are presented, as well as a discussion of the energetics of the catalytic processes and other salient features. The aim of this review is to provide the reader with a contemporary physical organic description of phosphorothioate ester cleavage. This article is part of a Special Issue entitled: Chemistry and mechanism of phosphatases, diesterases and triesterases. ► Discuss categories of phosphorothioate (PPT) esters and reactions in solution. ► Mx+ catalysts promote the cleavage of PPT triesters with a bridging S in methanol. ► Discussion of the Pd(II) catalysts promoting the solvolysis of PPT pesticides. ► Quantitative measure of Pd(II) catalysis for a methanolysis of a PPT pesticide. ► Transition state bound by catalyst strong enough to convert it into intermediate.