Novel Synthesis of [<sup>33</sup>P]-(2-Chloroethyl)phosphonic Acid

Zhang, Nanjing; Casida, John E.

doi:10.1021/jo0013608

Cited by 9 publications

(4 citation statements)

References 10 publications

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“…Fluorescence spectra were acquired on a Horiba FL3–21tau fluorescence spectrometer. P(SiMe 3 ) 3 and ODPA were prepared according to literature procedures. ,− …”

Section: Methodsmentioning

confidence: 99%

Two-Step Nucleation and Growth of InP Quantum Dots via Magic-Sized Cluster Intermediates

et al. 2015

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We report on the role of magic-sized clusters (MSCs) as key intermediates in the synthesis of indium phosphide quantum dots (InP QDs) from molecular precursors. Heterogeneous growth from the MSCs directly to InP QDs was observed without intermediate sized particles. These observations suggest that previous efforts to control nucleation and growth by tuning precursor reactivity have been undermined by formation of these kinetically persistent MSCs prior to QD formation. The thermal stability of InP MSCs is influenced by the presence of exogenous bases as well as choice of the anionic ligand set. Addition of a primary amine, a common additive in previous InP QD syntheses, to carboxylate terminated MSCs was found to bypass the formation of MSCs, allowing for homogeneous growth of InP QDs through a continuum of isolable sizes. Substitution of the carboxylate ligand set for a phosphonate ligand set increased the thermal stability of one particular InP MSC to 400 °C. The structure and optical properties of the MSCs with both carboxylate and phosphonate ligand sets were studied by UV-Vis absorption spectroscopy, powder XRD analysis, and solution 31 P{ 1 H} and 1 H NMR spectroscopy. Finally, the carboxylate terminated MSCs were identified as effective single source precursors (SSPs) for the synthesis of high quality InP QDs. Employing InP MSCs as SSPs for QDs effectively decouples the formation of MSCs from the subsequent second nucleation event and growth of InP QDs. The concentration dependence of this SSP reaction, as well as the shape uniformity of particles observed by TEM suggests that the stepwise growth from MSCs directly to QDs proceeds via a second nucleation event rather than an aggregative growth mechanism.

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“…Fluorescence spectra were acquired on a Horiba FL3–21tau fluorescence spectrometer. P(SiMe 3 ) 3 and ODPA were prepared according to literature procedures. ,− …”

Section: Methodsmentioning

confidence: 99%

Two-Step Nucleation and Growth of InP Quantum Dots via Magic-Sized Cluster Intermediates

et al. 2015

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“…Chemicals. Ethephon was obtained from Chem Service (West Chester, PA) and [ 33 P]ethephon (0.42 mCi/mmol) was prepared in the Berkeley laboratory (9). Reagents for nativeand sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) included SDS from Boehringer Mannheim (Indianapolis, IN); Coomassie Brilliant Blue R-250 and 2-mercaptoethanol (BME) from Bio-Rad (Hercules, CA); bromophenol blue and dithiothreitol (DTT) from Fisher (Fair Lawn, NJ); molecular weight marker proteins from Bio-Rad and GibcoBRL (Gaithersburg, MD).…”

Section: Methodsmentioning

confidence: 99%

Specificity of Ethephon as a Butyrylcholinesterase Inhibitor and Phosphorylating Agent

Haux

Lockridge

Casida

2002

Chem. Res. Toxicol.

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Butyrylcholinesterase (BChE) is inhibited by the plant growth regulator (2-chloroethyl)phosphonic acid (ethephon) as observed 25 years ago both in vitro and in vivo in rats and mice and more recently in subchronic studies at low doses with human subjects. The proposed mechanism is phosphorylation of the BChE active site at S198 by ethephon dianion. The present study tests this hypothesis directly using [(33)P]ethephon and recombinant BChE (rBChE) with single amino acid substitutions and further evaluates if BChE is the most sensitive esterase target in vitro and with mice in vivo. [(33)P]Ethephon labels purified rBChE but not enzymatically inactive diethylphosphoryl-rBChE (derivatized at S198 by preincubation with chlorpyrifos oxon) or several other esterases and proteins. Amino acid substitutions that greatly reduce rBChE sensitivity to ethephon are G117H and G117K in the oxyanion hole (which may interfere with hydrogen bonding between glycine-N-H and ethephon dianion) and A328F, A328W, and A328Y (perhaps by impeding access to the active site gorge). Other substitutions that do not affect sensitivity are D70N, D70K, D70G, and E197Q which are not directly involved in the catalytic triad. The effect of pH and buffer composition on inhibition supports the hypothesis that ethephon dianion is the actual phosphorylating agent without activation by divalent cations. Human plasma BChE in vitro and mouse plasma BChE in vitro and in vivo are more sensitive to ethephon than any other esterases detected by butyrylthiocholine or 1-naphthyl acetate hydrolysis in native-PAGE. All mouse liver esterases observed are less sensitive than plasma BChE to ethephon in vitro and in vivo. More than a dozen other esterases examined are 10-100-fold less sensitive than BChE to ethephon. Thus, BChE inhibition continues to be the most sensitive marker of ethephon exposure.

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“…Alternatively, this reaction can be used to reduce P(V) compounds into the corresponding P(III) derivatives [3][4][5][6][7][8][9][10]. Although the transformations involving transfer of sulfur or selenium are rather common, there are only a few reports in literature on the oxygen transfer reaction [11,12] and these involve exclusively phosphine oxides with at least one leaving group as donors.…”

Section: Introductionmentioning

confidence: 99%

“…Mechanism 1, which involves a nucleophilic attack of a P(III) species on the phosphorus centre of a P(V) compound that may proceed via a three-membered cyclic transition state, and Mechanism 2, which is an X-philic attack of a P(III) compound on the chalcogen of the P(V) species and involves a linear transition state. The former mechanism, postulated for the selenium exchange reaction [2], could account for the fact that oxygen transfer is facilitated by the presence of strong electron-withdrawing groups [11,12], while the later one, was claimed to be consistent with the observed a second order kinetics for the sulfur transfer process [8] and it was also proposed for the oxygen transfer from phosphorus oxychloride to trialkylphosphine [13].…”

Section: Introductionmentioning

confidence: 99%

Theoretical investigations on the mechanism of chalcogens exchange reaction between P(V) and P(III) compounds

Kullberg¹,

Stawiński²

2005

Journal of Organometallic Chemistry

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Novel Synthesis of [³³P]-(2-Chloroethyl)phosphonic Acid

Cited by 9 publications

References 10 publications

Two-Step Nucleation and Growth of InP Quantum Dots via Magic-Sized Cluster Intermediates

Two-Step Nucleation and Growth of InP Quantum Dots via Magic-Sized Cluster Intermediates

Specificity of Ethephon as a Butyrylcholinesterase Inhibitor and Phosphorylating Agent

Theoretical investigations on the mechanism of chalcogens exchange reaction between P(V) and P(III) compounds

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Novel Synthesis of [33P]-(2-Chloroethyl)phosphonic Acid

Cited by 9 publications

References 10 publications

Two-Step Nucleation and Growth of InP Quantum Dots via Magic-Sized Cluster Intermediates

Two-Step Nucleation and Growth of InP Quantum Dots via Magic-Sized Cluster Intermediates

Specificity of Ethephon as a Butyrylcholinesterase Inhibitor and Phosphorylating Agent

Theoretical investigations on the mechanism of chalcogens exchange reaction between P(V) and P(III) compounds

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Product

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Novel Synthesis of [³³P]-(2-Chloroethyl)phosphonic Acid