P-S Bond Scission by Bis(cyclopentadienyl)molybdenum(IV) Dichloride, Cp2MoCl2(aq): First Documented Example of an Organometallic Complex Hydrolyzing Thiophosphinates
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- 作者：Louis Y. Kuo ; Angela P. Blum ; and Michal Sabat
- 刊名：Inorganic Chemistry
- 出版年：2005
- 出版时间：July 25, 2005
- 年：2005
- 卷：44
- 期：15
- 页码：5537 - 5541
- 全文大小：80K
- 年卷期：v.44,no.15(July 25, 2005)
- ISSN：1520-510X
文摘
Thiophosphinate hydrolysis involving P-S bond scission is desirable for the degradation of organophosphateneurotoxins, and we report the first case for such a hydrolytic process by an organometallic compound. Themetallocene, bis(cyclopentadienyl)molybdenum(IV) dichloride, Cp2MoCl2 (Cp = 
5-C5H5), hydrolyzes a variety ofthioaryl diphenylphosphinates in an aqueous THF solution. P-S scission of p-methoxythiophenyl diphenylphosphinatehas a 500-fold rate of acceleration in the presence of Cp2MoCl2(aq) with activation parameters of 20(3) kcal mol-1and -15(3) cal mol-1 K-1 for 
H
and S, respectively. These activation parameters and the rate accelerationare consistent with an intermolecular hydrolytic process in which the Cp2Mo serves as a Lewis acid to activate thephosphinate for nucleophilic attack. Furthermore, 
= 2.3 (25 
C) which indicates a single nonconcerted mechanismin which the rate determining step is the nucleophilic attack on the activated phosphinate.
5-C5H5), hydrolyzes a variety ofthioaryl diphenylphosphinates in an aqueous THF solution. P-S scission of p-methoxythiophenyl diphenylphosphinatehas a 500-fold rate of acceleration in the presence of Cp2MoCl2(aq) with activation parameters of 20(3) kcal mol-1and -15(3) cal mol-1 K-1 for H and S, respectively. These activation parameters and the rate accelerationare consistent with an intermolecular hydrolytic process in which the Cp2Mo serves as a Lewis acid to activate thephosphinate for nucleophilic attack. Furthermore, = 2.3 (25 C) which indicates a single nonconcerted mechanismin which the rate determining step is the nucleophilic attack on the activated phosphinate.