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5356322 
Journal Article 
Paraoxon and parathion hydrolysis by aqueous molybdenocene dichloride (Cp2MoCl2): first reported pesticide hydrolysis by an organometallic complex 
Kuo, LY; Perera, NM 
2000 
Yes 
Inorganic Chemistry
ISSN: 0020-1669
EISSN: 1520-510X 
39 
10 
2103-2106 
English 
12526519 
WOS:000087124000015 
We report the first case of an organometallic complex that effectively hydrolyzes the organophosphate pesticides parathion and paraoxon. The complex is the water-soluble compound bis(eta 5-cyclopentadienyl)molybdenum(IV) dichloride (1), which hydrolyzes parathion to produce ethanol and deethyl parathion in a biphasic reaction in D2O. Rate accelerations were 130 and 10(5) at pH 7 and 3, respectively. Paraoxon is readily hydrolyzed by 1 to yield p-nitrophenol and diethyl phosphate with rate accelerations of 2300 and 27 at pH 7 and 3, respectively. Kinetic data for paraoxon hydrolysis by 1 are consistent with a process that involves intermolecular (delta S++ = -49 +/- 10 eu) hydroxide attack on the phosphate triester in which the aquated 1 serves as a coordinated Lewis acid that activates the organophosphate. Interestingly parathion hydrolysis by 1 occurs via nucleophilic attack at the alpha-carbon of the phosphorothioate pesticide that involves C-O bond cleavage. These parathion results represent one of the few cases of this type of unusual hydrolytic chemistry and the first case of an organometallic complex that accelerates organophosphate pesticide hydrolysis.