Phosphonothioate Hydrolysis Turnover by Cp₂MoCl₂ and Silver Nanoparticles

Abstract

The metallocene bis(cyclopentadienyl)molybdenum(IV) dichloride (Cp2MoCl2; Cp = η5-C5H5) is the first organometallic compound to promote the hydrolysis of phosphonothioates with selective P–S scission in a stoichiometric fashion. This report shows that silver nanoparticles capped with borohydride ions promote turnover in this hydrolytic process, as indicated by 31P NMR studies on the reaction of O,S-diethyl phenylphosphonothioate (DEPP) with Cp2MoCl2 (pH 7). This is the first example of the joint use of nanoparticles and molybdenum metallocenes to promote phosphonothioate hydrolysis. Initial results indicate the turnover may be due to free Ag+(aq) ions present in the solution that arise either from the slow dissolution of the nanoparticles or from interactions with the Ag nanoparticle surface.

Non-photochemical catalytic hydrolysis of methyl parathion using core–shell Ag@TiO2 nanoparticles

“…The role of Ag + ions in hydrolysis of organophosphates has previously been described, suggesting the possibility that free Ag + ion may be responsible for catalytic hydrolysis of methyl parathion in our experiments. 36 Under catalytic conditions, we measured free silver ion in solution by atomic absorption spectroscopy which gave a value of 2.38 ppm after 6 hours. This value is too low to show any catalytic activity for MeP hydrolysis.…”

“…This value is too low to show any catalytic activity for MeP hydrolysis. 36 Interestingly, the dark antibacterial activity of Ag@TiO 2 has been described, and explained as due to the slow dissolution of AgNPs and formation of toxic Ag + ions in solution. The efficiency of Ag@TiO 2 recycle for MeP hydrolysis was tested over a period of 24 hours (Fig.…”

[Cp2Mo(OH)(OH2)]+‐Catalyzed Hydrolysis of Mono‐ and Difunctional Ethers: Theoretical Understanding of Their Divergent Reactivity

“…Specifically, they have proven to be efficient when catalyzing a variety of organic reactions: H/D exchange in alcohols, [41][42][43] hydrogenation of olefins, [36] nitrile hydration, [37][38][39][44][45][46] carbon monoxide oxidation, [45] and hydrolysis of ethers, [45] esters of carboxylic acids, [36,37,45] and various organophosphates. [37,[45][46][47][48][49][50][51] valuable to corroborate and rationalize the experimental belief that the intramolecular nucleophilic attack of the hydroxo ligand on the Mo-coordinated substrate is the operative mechanism (see Scheme 1). [36,44,45] In accordance with experimental suggestions, [44,45] this mechanism begins with the replacement of the aqua ligand of the catalytically active complex [Cp 2 Mo-(OH)(OH 2 )] + by the substrate (XY in Scheme 1).…”

“…The presence of an open coordination site and an internal hydroxo ligand in these hydroxo complexes significantly enhances the catalytic effectiveness of aqueous molybdocenes. Specifically, they have proven to be efficient when catalyzing a variety of organic reactions: H/D exchange in alcohols, hydrogenation of olefins, nitrile hydration,, carbon monoxide oxidation, and hydrolysis of ethers, esters of carboxylic acids,, , and various organophosphates , …”

Detoxification of organophosphates using imidazole-coated Ag, Au and AgAu nanoparticles

“…5 In this context, imidazole-derived catalysts have attracted great attention due to their presence in many enzymatic active sites and their chemical versatility, 11 i.e., they can react as acid-base or nucleophilic catalysts under considerably mild conditions (pH $ 7). 12,13 Another promising class of catalysts for OP cleavage involve nanoparticles (NPs), 14 although there are still only a few reports in this eld, 5,[15][16][17][18][19][20] in contrast to the many studies regarding NPs-based sensors for various OP. 21 The physicochemical features of several NPs, such as shape and size, can be decisive for catalysis.…”