15959-01-0Relevant articles and documents
An ortho-palladated dimethylbenzylamine complex as a highly efficient turnover catalyst for the decomposition of P=S insecticides. Mechanistic studies of the methanolysis of some P=S-containing phosphorothioate triesters
Lu, Zhong-Lin,Neverov, Alexei A.,Brown, R. Stan
, p. 3379 - 3387 (2005)
An ortho-palladated complex Pd(dmba)(py)(OTf) (9), or Pd(N,N- dimethylbenzylamine)(pyridine)-(trifluoromethanesulfonate), was synthesized and its solution properties in methanol studied as a function of s spH. In neutral solution the triflate dissociates from the complex to give a dominant form Pd(dmba)(py)(HOCH3), and in acid the pyridine dissociates to give Pyr-H+ and Pd(dmba)(HOCH3)(HOCH 3). Under basic conditions, Pd(dmba)(py)(HOCH3) ionizes to give Pd(dmba)(py)(-OCH3) from which the pyridine can dissociate to yield a mixture of a bis-methoxy-bridged dimer (Pd(dmba)( -OCH3))2 (15-dimer), and its monomer Pd(dmba)(HOCH3)-(-OCH3). Kinetic studies under buffered conditions reveal that 9 is an effective catalyst for the methanolysis of fenitrothion and other P=S pesticides. The active form of the catalyst is a basic one having one associated methoxide generated with an apparent sspKa of 10.8. Analysis of the change in the UV/vis spectrum as a function of sspH generates a spectrophotometric ssKa of 10.8 ±0.1. This catalytic system is shown to promote the methanolysis of fenitrothion (3), diazinon (4), quinalphos (5), coumaphos (10) and dichlofenthion (11) at 0.05 mol dm-3 triethyl amine buffer, sspH 10.8, 25°C, under turnover conditions where the [phosphorothioate]/[9] ratio is 48.6, 13.4, 13.4, 18.6, and 48.6 respectively. In all cases, the products were derived from displacement of the leaving group by methoxide, the second-order turnover rate constants being 36.9, 0.45, 0.12, > 146.7 and 44.3 dm 3 mol-1 s-1 respectively. An associative mechanism for the catalyzed methanolysis of the P=S pesticides is proposed where a transiently coordinated S=P substrate is intramolecularly attacked by the PdII-coordinated methoxide. The Royal Society of Chemistry 2005.
Reactions of N'-cyano-N-phenylformamidine and carbodiimide with phosphorodithioic acid O,O-diethyl ester
Fedgenhaeuer,Moll
, p. 141 - 142 (2007/10/02)
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