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Palos E, Caruso A, Paesani F. Consistent density functional theory-based description of ion hydration through density-corrected many-body representations. J Chem Phys 2023; 159:181101. [PMID: 37947509 DOI: 10.1063/5.0174577] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023] Open
Abstract
Delocalization error constrains the accuracy of density functional theory in describing molecular interactions in ion-water systems. Using Na+ and Cl- in water as model systems, we calculate the effects of delocalization error in the SCAN functional for describing ion-water and water-water interactions in hydrated ions, and demonstrate that density-corrected SCAN (DC-SCAN) predicts n-body and interaction energies with an accuracy approaching coupled cluster theory. The performance of DC-SCAN is size-consistent, maintaining an accurate description of molecular interactions well beyond the first solvation shell. Molecular dynamics simulations at ambient conditions with many-body MB-SCAN(DC) potentials, derived from the many-body expansion, predict the solvation structure of Na+ and Cl- in quantitative agreement with reference data, while simultaneously reproducing the structure of liquid water. Beyond rationalizing the accuracy of density-corrected models of ion hydration, our findings suggest that our unified density-corrected MB formalism holds great promise for efficient DFT-based simulations of condensed-phase systems with chemical accuracy.
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Affiliation(s)
- Etienne Palos
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
| | - Alessandro Caruso
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
| | - Francesco Paesani
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
- Materials Science and Engineering, University of California San Diego, La Jolla, California 92093, USA
- San Diego Supercomputer Center, University of California San Diego, La Jolla, California 92093, USA
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Onyido I, Obumselu OF, Egwuatu CI, Okoye NH. Solvent and solvation effects on reactivities and mechanisms of phospho group transfers from phosphate and phosphinate esters to nucleophiles. Front Chem 2023; 11:1176746. [PMID: 37179775 PMCID: PMC10172589 DOI: 10.3389/fchem.2023.1176746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/03/2023] [Indexed: 05/15/2023] Open
Abstract
Organophosphorus esters fulfil many industrial, agricultural, and household roles. Nature has deployed phosphates and their related anhydrides as energy carriers and reservoirs, as constituents of genetic materials in the form of DNA and RNA, and as intermediates in key biochemical conversions. The transfer of the phosphoryl (PO3) group is thus a ubiquitous biological process that is involved in a variety of transformations at the cellular level such as bioenergy and signals transductions. Significant attention has been paid in the last seven decades to understanding the mechanisms of uncatalyzed (solution) chemistry of the phospho group transfer because of the notion that enzymes convert the dissociative transition state structures in the uncatalyzed reactions into associative ones in the biological processes. In this regard, it has also been proposed that the rate enhancements enacted by enzymes result from the desolvation of the ground state in the hydrophobic active site environments, although theoretical calculations seem to disagree with this position. As a result, some attention has been paid to the study of the effects of solvent change, from water to less polar solvents, in uncatalyzed phospho transfer reactions. Such changes have consequences on the stabilities of the ground and the transition states of reactions which affect reactivities and, sometimes, the mechanisms of reactions. This review seeks to collate and evaluate what is known about solvent effects in this domain, especially their effects on rates of reactions of different classes of organophosphorus esters. The outcome of this exercise shows that a systematized study of solvent effects needs to be undertaken to fully understand the physical organic chemistry of the transfer of phosphates and related molecules from aqueous to substantially hydrophobic environments, since significant knowledge gaps exist.
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Liang Z, Chen X, Yang Z, Liu Y, Qiu X, Zeng Z, Lu S, Liu Y. Sodium Ions Affect Pyrraline Formation in the Maillard Reaction With Lys-Containing Dipeptides and Tripeptides. Front Nutr 2022; 9:874650. [PMID: 35399664 PMCID: PMC8990318 DOI: 10.3389/fnut.2022.874650] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 02/25/2022] [Indexed: 11/25/2022] Open
Abstract
Advanced glycation end products (AGEs) are potentially-hazardous chemical compounds, produced by the Maillard reaction between reducing sugars and Lysine side-chain amino groups in proteins. AGEs are strongly associated with diabetes, Alzheimer's disease and atherosclerosis. Pyrraline, a sugar derivative of Lysine, is a major AGE and an established marker for the presence of dietary AGEs. In this study, the effects of NaCl and different dipeptide and tripeptide structures were compared on the formation of pyrraline-containing peptides and the glucose derivative 3-deoxyglucosone in the presence of glucose and at different NaCl concentrations. The physicochemical properties (polarizability, dipole moment, molecular volume and dissociation constant) and the thermodynamic properties of the peptides were determined. The amount of the pyrraline decreased significantly in the following order of peptides (at the same concentrations): Lys-Phe > Lys-Ala > Lys-Gly; Lys-Gly-Phe > Lys-Gly-Ala > Lys-Gly-Gly. The highest levels of both pyrraline and 3-deoxyglucosone occurred at 0.2 mol/L Na+. Sodium ions appear to alter the intramolecular electron density and charge distribution of the peptides and facilitate the reaction by stabilizing some of the intermediates in the reaction sequence.
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Affiliation(s)
- Zhili Liang
- School of Food Science, Guangdong Food and Drug Vocational College, Guangzhou, China
| | - Xu Chen
- Engineering Research Center of Health Food Design and Nutrition Regulation, School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan, China
| | - Zhao Yang
- School of Food Science, Guangdong Food and Drug Vocational College, Guangzhou, China
| | - Yan Liu
- School of Food Science, Guangdong Food and Drug Vocational College, Guangzhou, China
| | - Xueying Qiu
- School of Food Science, Guangdong Food and Drug Vocational College, Guangzhou, China
| | - Zhenzhen Zeng
- School of Food Science, Guangdong Food and Drug Vocational College, Guangzhou, China
| | - Shuidi Lu
- School of Food Science, Guangdong Food and Drug Vocational College, Guangzhou, China
| | - Yuehan Liu
- School of Food Science, Guangdong Food and Drug Vocational College, Guangzhou, China
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Caruso A, Paesani F. Data-driven many-body models enable a quantitative description of chloride hydration from clusters to bulk. J Chem Phys 2021; 155:064502. [PMID: 34391363 DOI: 10.1063/5.0059445] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We present a new data-driven potential energy function (PEF) describing chloride-water interactions, which is developed within the many-body-energy (MB-nrg) theoretical framework. Besides quantitatively reproducing low-order many-body energy contributions, the new MB-nrg PEF is able to correctly predict the interaction energies of small chloride-water clusters calculated at the coupled cluster level of theory. Importantly, classical and quantum molecular dynamics simulations of a single chloride ion in water demonstrate that the new MB-nrg PEF predicts x-ray spectra in close agreement with the experimental results. Comparisons with an popular empirical model and a polarizable PEF emphasize the importance of an accurate representation of short-range many-body effect while demonstrating that pairwise additive representations of chloride-water and water-water interactions are inadequate for correctly representing the hydration structure of chloride in both gas-phase clusters and solution. We believe that the analyses presented in this study provide additional evidence for the accuracy and predictive ability of the MB-nrg PEFs, which can then enable more realistic simulations of ionic aqueous systems in different environments.
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Affiliation(s)
- Alessandro Caruso
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
| | - Francesco Paesani
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
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Kalu GI, Ubochi CI, Onyido I. Reactions of aryl dimethylphosphinothioate esters with anionic oxygen nucleophiles: transition state structure in 70% water-30% ethanol. RSC Adv 2021; 11:8833-8845. [PMID: 35423373 PMCID: PMC8695247 DOI: 10.1039/d0ra10759j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 02/03/2021] [Indexed: 11/21/2022] Open
Abstract
Aryl dimethylphosphinates, 2, react with anionic oxygen nucleophiles in water via a concerted (ANDN) mechanism. With EtO- in anhydrous ethanol, the mechanism is associative (AN + DN), with rate-limiting pentacoordinate intermediate formation. This change in mechanism with solvent change has been ascribed to changes in the nucleophile and leaving group basicities accompanying solvent change. This paper reports on a kinetic analysis of the reactions of the aryl dimethylphosphinothioates, 3a-g, with oxygen nucleophiles in 70% water-30% ethanol (v/v) solvent at 25 °C, reactions known to proceed by a concerted mechanism in water, to test the rationalization stated above, since the nucleophiles and LGs of interest are more basic in aqueous ethanol than in water. The change in solvent causes an ca. 14 to 320-fold decrease in rate. Hammett and Brønsted-type correlations characterize a concerted TS with less P-LG bonding in aqueous ethanol than in water. Two opposing consequences are associated with the solvent change: (a) increased basicity of nucleophiles and LGs, which lead to a modest tightening of the TS; and (b) better stabilization of the IS relative to the TS in aqueous ethanol, which results in a slower reaction with a more product-like TS. Hammond and anti-Hammond effects on the TS arising from better stabilization of the IS over the TS dominate over the effects of increased nucleophile and LG basicity in determining the looser TS structure in aqueous ethanol. An altered TS structure is consistent with an altered reaction potential energy surface, in this case caused by a change in solvent polarity.
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Affiliation(s)
- Georgina I Kalu
- Department of Chemistry, Imo State University Owerri Nigeria
| | | | - Ikenna Onyido
- Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University Awka Nigeria +234-806-268-5122
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Bajaj P, Richardson JO, Paesani F. Ion-mediated hydrogen-bond rearrangement through tunnelling in the iodide–dihydrate complex. Nat Chem 2019; 11:367-374. [DOI: 10.1038/s41557-019-0220-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 01/22/2019] [Indexed: 11/09/2022]
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Riera M, Brown SE, Paesani F. Isomeric Equilibria, Nuclear Quantum Effects, and Vibrational Spectra of M+(H2O)n=1–3 Clusters, with M = Li, Na, K, Rb, and Cs, through Many-Body Representations. J Phys Chem A 2018; 122:5811-5821. [DOI: 10.1021/acs.jpca.8b04106] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Bromberg L, Creasy WR, McGarvey DJ, Wilusz E, Hatton TA. Nucleophilic Polymers and Gels in Hydrolytic Degradation of Chemical Warfare Agents. ACS APPLIED MATERIALS & INTERFACES 2015; 7:22001-22011. [PMID: 26359671 DOI: 10.1021/acsami.5b06905] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Water- and solvent-soluble polymeric materials based on polyalkylamines modified with nucleophilic groups are introduced as catalysts of chemical warfare agent (CWA) hydrolysis. A comparative study conducted at constant pH and based on the criteria of the synthetic route simplicity, aqueous solubility, and rate of hydrolysis of CWA mimic, diisopropylfluorophosphate (DFP), indicated that 4-aminopyridine-substituted polyallylamine (PAAm-APy) and polyvinylamine substituted with 4-aminopyridine (PVAm-APy) were advantageous over 4-pyridinealdoxime-modified PVAm and PAAm, poly(butadiene-co-pyrrolidinopyridine), and PAAm modified with bipyridine and its complex with Cu(II). The synthesis of PVAm-APy and PAAm-APy involved generation of a betaine derivative of acrylamide and its covalent attachment onto the polyalkylamine chain followed by basic hydrolysis. Hydrogel particles of PAAm-APy and PVAm-APy cross-linked by epichlorohydrin exhibited pH-dependent swelling and ionization patterns that affected the rate constants of DFP nucleophilic hydrolysis. Deprotonation of the aminopyridine and amine groups increased the rates of the nucleophilic hydrolysis. The second-order rate of nucleophilic hydrolysis was 5.5- to 10-fold higher with the nucleophile-modified gels compared to those obtained by cross-linking of unmodified PAAm, throughout the pH range. Testing of VX and soman (GD) was conducted in 2.5-3.7 wt % PVAm-APy suspensions or gels swollen in water or DMSO/water mixtures. The half-lives of GD in aqueous PVAm-APy were 12 and 770 min at pH 8.5 and 5, respectively. Addition of VX into 3.5-3.7 wt % suspensions of PVAm-APy in DMSO-d6 and D2O at initial VX concentration of 0.2 vol % resulted in 100% VX degradation in less than 20 min. The unmodified PVAm and PAAm were 2 orders of magnitude less active than PVAm-APy and PAAm-APy, with VX half-lives in the range of 24 h. Furthermore, the PVAm-APy and PAAm-APy gels facilitated the dehydrochlorination reaction of sulfur mustard (HD) and its analogue 2-chloroethyl ethylsulfide (CEES). The ability of the reported aminopyridine-modified polyalkylamine materials to degrade the most persistent of CWAs, coupled with aqueous solubility, and the presence of numerous amino groups that provide convenient "handles" for covalent attachment on polymeric and inorganic supports yields promise for applications such as protective fabric and textile treatment and components of decontaminating materials.
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Affiliation(s)
- Lev Bromberg
- Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - William R Creasy
- Leidos Corp. , P.O. Box 68, Gunpowder, Maryland 21010, United States
| | - David J McGarvey
- Analytical Toxicology Branch, R&T Directorate, U.S. Army Edgewood Chemical and Biological Center , Aberdeen Proving Ground, Maryland 21010, United States
| | - Eugene Wilusz
- Materials Science and Engineering Branch, U.S. Army Natick Soldier Research, Development & Engineering Center , Natick, Massachusetts 01760, United States
| | - T Alan Hatton
- Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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Yang K, Kim MY, Um IH. S NAr Reactions of 1-Halo-2,4-dinitrobenzenes with Alkali-Metal Ethoxides: Differential Stabilization of Ground State and Transition State Determines Alkali-Metal Ion Catalysis or Inhibition. B KOREAN CHEM SOC 2015. [DOI: 10.1002/bkcs.10344] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Kiyull Yang
- Department of Chemistry Education; Gyeongsang National University; Jinju 660-701 Korea
| | - Min-Young Kim
- Department of Chemistry and Nano Science; Ewha Womans University; Seoul 120-750 Korea
| | - Ik-Hwan Um
- Department of Chemistry and Nano Science; Ewha Womans University; Seoul 120-750 Korea
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Mayes HB, Nolte MW, Beckham GT, Shanks BH, Broadbelt LJ. The Alpha–Bet(a) of Salty Glucose Pyrolysis: Computational Investigations Reveal Carbohydrate Pyrolysis Catalytic Action by Sodium Ions. ACS Catal 2014. [DOI: 10.1021/cs501125n] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Heather B. Mayes
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Michael W. Nolte
- Department
of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States
| | - Gregg T. Beckham
- National
Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Brent H. Shanks
- Department
of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States
- Center
for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, Iowa 50011, United States
| | - Linda J. Broadbelt
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
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Kim MY, Ha GH, Um IH. Alkali-Metal Ion Catalysis and Inhibition in S NAr Reaction of 1-Halo-2,4-dinitrobenzenes with Alkali-Metal Ethoxides in Anhydrous Ethanol. B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.8.2438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Im HJ, Lee J, Kim MY, Um IH. K +Ion Catalysis in Nucleophilic Displacement Reaction of Y-Substituted-Phenyl Picolinates with Potassium Ethoxide: Effect of Substituent Y on Reactivity and Transition State Structure. B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.6.1749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Jeon SH, Yoon JH, Kim MY, Um IH. Alkali-Metal Ion Catalysis in Nucleophilic Substitution Reactions of 5-Nitro-8-quinolyl Picolinate with Alkali Metal Ethoxides: Effect of Modification of Nonleaving Group from Benzoyl to Picolinyl on Reactivity and Transition State Structure. B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.5.1506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kim SI, Cho HJ, Um IH. Nucleophilic Substitution Reactions of Y-Substituted-Phenyl Benzoates with Potassium Ethoxide in Anhydrous Ethanol: Reaction Mechanism and Role of K+Ion. B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.1.177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kim SI, Kim MY, Um IH. Kinetic Study on Nucleophilic Substitution Reactions of 4-Nitrophenyl X-Substituted-Benzoates with Potassium Ethoxide: Reaction Mechanism and Role of K+Ion. B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.1.225] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Keller BO, Esbata AA, Buncel E, van Loon GW. Rapidly formed quinalphos complexes with transition metal ions characterized by electrospray ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:1319-1328. [PMID: 23681809 DOI: 10.1002/rcm.6570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 02/07/2013] [Accepted: 02/08/2013] [Indexed: 06/02/2023]
Abstract
RATIONALE Electrospray ionization tandem mass spectrometry (ESI-MS/MS) offers the unique opportunity to characterize complexes of the organophosphorus pesticide (OP) quinalphos (PA-Q) with transition metal ions immediately formed after contact. This study complements research looking at longer term kinetics of quinalphos hydrolysis in the presence of transition metal ions and gives insights into the structural features of the initial complex formation in solution. (Hydrolysis reaction: PA-Q + H2 O → PA-OH + HQ, where PA-OH is the diethyl phosphate product and HQ is hydroxyquinoxaline.) METHODS Low micromolar PA-Q solutions with an approximately 3-fold molar excess of transition metal ions were immediately analyzed after mixing. Fragmentation of the transition metal ion complexes with PA-Q was accomplished in two different ways: first, in-source fragmentation by elevating the declustering potential and second, low-energy collision-induced dissociation (CID). RESULTS For Ag(+), the [PA-Q - Ag(+)] and respective Ag(+) -containing degradation product ions are readily observed. For Cu(2+), we observed the [PA-Q + Cu(2+) + NO3(-)] complex ion with weak intensity and strong signals from both the [2PA-Q + Cu(+)] and the [PA-Q + Cu(+)] ions, the latter two attributable to charge-state reduction in the gas phase from Cu(II) to Cu(I), indicating that PA-Q fulfills specific structural requirements of the formed complex for charge-state reduction during transition from solution to the gas phase. For Hg(2+), the [PA-Q + Hg(2+) + (PA-OH - H)(-)] ion was the largest observed species containing one Hg(2+) ion. No 1:1 species ([PA-Q] or other degradation products:Hg(2+)) was observable. CONCLUSIONS ESI-MS/MS of complexes formed from PA-Q and transition metal ions is a formidable technique to probe initial formation of these complexes in solution. Previous work from other groups established structural requirements that enable charge-state reduction from Cu(II) to Cu(I) in ligand complexes during transition into the gas phase, and these rules allow us to propose structural features of PA-Q complexes with copper ions in solution.
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Affiliation(s)
- Bernd O Keller
- Department of Pathology & Laboratory Medicine, University of British Columbia, Child & Family Research Institute, Vancouver, BC, V5Z 4H4, Canada.
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Um IH, Kang JS, Shin M. Alkali-Metal Ion Catalysis and Inhibition in Nucleophilic Displacement Reaction of O-Ethyl O-4-Nitrophenyl Phenylphosphonothioate with Alkali-Metal Ethoxides. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2013. [DOI: 10.1246/bcsj.20130015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Ik-Hwan Um
- Department of Chemistry and Nano Sciences, Ewha Womans University
| | - Ji-Sun Kang
- Department of Chemistry and Nano Sciences, Ewha Womans University
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Um IH, Song YJ, Kim MY, Lee JI. Metal-Ion Catalysis in Alkaline Ethanolysis of 2-Pyridyl Thionobenzoate: Effects of Modification of Electrophilic Center from C=O to C=S. B KOREAN CHEM SOC 2013. [DOI: 10.5012/bkcs.2013.34.5.1525] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Um IH, Kang JS, Shin YH, Buncel E. A kinetic study on nucleophilic displacement reactions of aryl benzenesulfonates with potassium ethoxide: role of K+ ion and reaction mechanism deduced from analyses of LFERs and activation parameters. J Org Chem 2012; 78:490-7. [PMID: 23215678 DOI: 10.1021/jo302373y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pseudofirst-order rate constants (k(obsd)) have been measured spectrophotometrically for the nucleophilic substitution reactions of 2,4-dinitrophenyl X-substituted benzenesulfonates 4a-f and Y-substituted phenyl benzenesulfonates 5a-k with EtOK in anhydrous ethanol. Dissection of k(obsd) into k(EtO(-)) and k(EtOK) (i.e., the second-order rate constants for the reactions with the dissociated EtO(-) and ion-paired EtOK, respectively) shows that the ion-paired EtOK is more reactive than the dissociated EtO(-), indicating that K(+) ion catalyzes the reaction. The catalytic effect exerted by K(+) ion (e.g., the k(EtOK)/k(EtO(-)) ratio) decreases linearly as the substituent X in the benzenesulfonyl moiety changes from an electron-donating group (EDG) to an electron-withdrawing group (EWG), but it is independent of the electronic nature of the substituent Y in the leaving group. The reactions have been concluded to proceed through a concerted mechanism from analyses of the kinetic data through linear free energy relationships (e.g., the Brønsted-type, Hammett, and Yukawa-Tsuno plots). K(+) ion catalyzes the reactions by increasing the electrophilicity of the reaction center through a cyclic transition state (TS) rather than by increasing the nucleofugality of the leaving group. Activation parameters (e.g., ΔH(‡) and ΔS(‡)) determined from the reactions performed at five different temperatures further support the proposed mechanism and TS structures.
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Affiliation(s)
- Ik-Hwan Um
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
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Um IH, Seo JY, Kang JS, An JS. A Kinetic Study on Nucleophilic Displacement Reactions of Phenyl Y-Substituted-Phenyl Carbonates with Alkali Metal Ethoxides: Metal Ion Effect and Reaction Mechanism. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2012. [DOI: 10.1246/bcsj.20120104] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Ik-Hwan Um
- Department of Chemistry and Nano Science, Ewha Womans University
| | - Ji-Yoon Seo
- Department of Chemistry and Nano Science, Ewha Womans University
| | - Ji-Sun Kang
- Department of Chemistry and Nano Science, Ewha Womans University
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Um IH, Kang JS, Kim CW, Lee JI. Alkali-Metal Ion Catalysis in Alkaline Ethanolysis of 2-Pyridyl Benzoate and Benzyl 2-Pyridyl Carbonate: Effect of Modification of Nonleaving Group from Benzoyl to Benzyloxycarbonyl. B KOREAN CHEM SOC 2012. [DOI: 10.5012/bkcs.2012.33.2.519] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Um IH, Shin YH, Park JE, Kang JS, Buncel E. Alkali-Metal-Ion Catalysis and Inhibition in the Nucleophilic Displacement Reaction of Y-Substituted Phenyl Diphenylphosphinates and Diphenylphosphinothioates with Alkali-Metal Ethoxides: Effect of Changing the Electrophilic Center from PO to PS. Chemistry 2011; 18:961-8. [DOI: 10.1002/chem.201102404] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Indexed: 11/11/2022]
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An JS, NamKoong G, Kang JS, Um IH. Alkali Metal Ion Catalysis and Inhibition in Nucleophilic Substitution Reactions of 3,4-Dinitrophenyl Diphenylphosphinothioate with Alkali Metal Ethoxides in Anhydrous Ethanol: Effect of Changing Electrophilic Center from P=O to P=S. B KOREAN CHEM SOC 2011. [DOI: 10.5012/bkcs.2011.32.7.2423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Choi SY, Hong YJ, Um IH. Metal Ion Catalysis and Inhibition in Nucleophilic Substitution Reactions of 4-Nitrophenyl Nicotinate and Isonicotinate with Alkali Metal Ethoxides in Anhydrous Ethanol. B KOREAN CHEM SOC 2011. [DOI: 10.5012/bkcs.2011.32.6.1951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Um IH, Seo JA, Mishima M. Kinetic and Theoretical Studies on Alkaline Ethanolysis of 4-Nitrophenyl Salicylate: Effect of Alkali Metal Ions on Reactivity and Mechanism. Chemistry 2011; 17:3021-7. [DOI: 10.1002/chem.201002692] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Indexed: 11/08/2022]
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Lee JI, Kang JS, Im LR, Um IH. Metal Ion Catalysis in Nucleophilic Displacement Reactions of 2-Pyridyl X-Substituted Benzoates with Potassium Ethoxide in Anhydrous Ethanol. B KOREAN CHEM SOC 2010. [DOI: 10.5012/bkcs.2010.31.12.3543] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Lee JI, Kang JS, Kim SI, Um IH. Effect of Alkali Metal Ions on Alkaline Ethanolysis of 2-Pyridyl and 4-Pyridyl Benzoates in Anhydrous Ethanol. B KOREAN CHEM SOC 2010. [DOI: 10.5012/bkcs.2010.31.10.2929] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Hong YJ, Kim SI, Um IH. Metal Ion Catalysis in Nucleophilic Substitution Reaction of 4-Nitrophenyl Picolinate with Alkali Metal Ethoxides in Anhydrous Ethanol. B KOREAN CHEM SOC 2010. [DOI: 10.5012/bkcs.2010.31.9.2483] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Seo JA, Kim SI, Hong YJ, Um IH. Effect of Alkali Metal Ions on Nucleophilic Substitution Reactions of 4-Nitrophenyl X-Substituted Benzoates with Alkali Metal Ethoxides in Anhydrous Ethanol. B KOREAN CHEM SOC 2010. [DOI: 10.5012/bkcs.2010.31.02.303] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Sánchez-Lombardo I, Yatsimirsky AK. Simplified Speciation and Improved Phosphodiesterolytic Activity of Hydroxo Complexes of Trivalent Lanthanides in Aqueous DMSO. Inorg Chem 2008; 47:2514-25. [DOI: 10.1021/ic701846e] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Irma Sánchez-Lombardo
- Facultad de Química, Universidad Nacional Autónoma de México, 04510 México D.F., México
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Churchill D, Dust JM, Buncel E. Concerted rate-limiting proton transfer to sulfur with nucleophilic attack at phosphorus — A new proposed mechanism for hydrolytic decomposition of the P=S pesticide, Diazinon, in moderately acidic sulfuric acid media. CAN J CHEM 2007. [DOI: 10.1139/v07-049] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We report herein the first kinetic study of a P=S containing organophosphorus pesticide, Diazinon (1), in the moderately concentrated acid region. Product analyses (31P NMR) show that reaction occurs only at the P centre. The rate-acidity profile (kobs vs. molarity of H2SO4) appears as a curve in which the initial slight downward trace (molarity = 1 to ca. 5) is followed by sharper upward curve (molarity ca. 5 to 14). Using treatments involving the excess acidity (X) method, the A-1 and A-2 mechanistic possibilities were found to be inoperative over the full acidity range. A novel mechanism is proposed for the higher acidity (X ca. 2–6) region. This mechanism involves proton transfer to P=S from hydronium ion with concomitant proton transfer from water, which effectively delivers hydroxide to the P centre in a variant of the A-SE2 process. A putative A-2 mechanism in this region is supplanted by the proposed A-SE2 variant where the cyclic array results in proton transfer being efficiently coupled with nucleophilic attack involving water. This constitutes the first report of rate-limiting proton transfer at the P=S functionality in acid hydrolysis of this class of organophosphorus neutroxins. A 600 000-fold acceleration in the decomposition of Diazinon is associated with the change of medium from neutral aqueous solution to the most acidic medium studied (X ca. 6). Key words: phosphorothioate ester hydrolysis, acid catalysis, rate-limiting proton transfer at P=S, excess acidity analysis, new A-SE2 variant mechanism.
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Gomez-Tagle P, Vargas-Zúñiga I, Taran O, Yatsimirsky AK. Solvent Effects and Alkali Metal Ion Catalysis in Phosphodiester Hydrolysis. J Org Chem 2006; 71:9713-22. [PMID: 17168589 DOI: 10.1021/jo061780i] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The kinetics of the alkaline hydrolysis of bis(p-nitrophenyl) phosphate (BNPP) have been studied in aqueous DMSO, dioxane, and MeCN. In all solvent mixtures the reaction rate steadily decreases to half of its value in pure water in the range of 0-70 vol % of organic cosolvent and sharply increases in mixtures with lower water content. Correlations based on different scales of solvent empirical parameters failed to describe the solvent effect in this system, but it can be satisfactorily treated in terms of a simplified stepwise solvent-exchange model. Alkali metal ions catalyze the BNPP hydrolysis but do not affect the rate of hydrolysis of neutral phosphotriester p-nitrophenyl diphenyl phosphate in DMSO-rich mixtures. The catalytic activity decreases in the order Li+ > Na+ > K+ > Rb+ > Cs+. For all cations except Na+, the reaction rate is first-order in metal ion. With Na+, both first- and second-order kinetics in metal ions are observed. Binding constants of cations to the dianionic transition state of BNPP alkaline hydrolysis are of the same order of magnitude and show a similar trend as their binding constants to p-nitrophenyl phosphate dianion employed as a transition-state model. The appearance of alkali metal ion catalysis in a medium, which solvates metal ions stronger than water, is attributed to the increased affinity of cations to dianions, which undergo a strong destabilization in the presence of an aprotic dipolar cosolvent.
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Affiliation(s)
- Paola Gomez-Tagle
- Facultad de Química, Universidad Nacional Autónoma de México, 04510 México D.F., México
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Balakrishnan VK, Buncel E, Vanloon GW. Micellar catalyzed degradation of fenitrothion, an organophosphorus pesticide, in solution and soils. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005; 39:5824-30. [PMID: 16124321 DOI: 10.1021/es050234o] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We report on a study of the decomposition of fenitrothion (an organophosphorus pesticide that is a persistent contaminant in soils and groundwater) as catalyzed by cetyltrimethylammonium (CTA+) micelles. The CTA micelles were associated with two types of counterions: (1) inert counterions (e.g. CTABr) and (2) reactive counterions (e.g. CTAOH). The reactive counterion surfactants used were hydroxide anion (HO-) as a normal nucleophile and hydroperoxide anion (HOO-) and the anion of pyruvaldehyde oxime (MINA-) as two alpha-nucleophiles. The reactivity order followed: CTABr < CTAOH < CTAMINA << CTAOOH. Treatment of the rate data using the Pseudo-Phase Ion Exchange (PPIE) model of micellar catalysis showed the ratio k2M/k2w to be less than unity for all the surfactants employed. Rather than arising from a "true catalysis", we attributed the observed rate enhancements to a "concentration effect", where both pesticide and nucleophile were incorporated into the small micellar phase volume. Furthermore, the CTAOOH/CTAOH pair gave an alpha-effect of 57, showing that the alpha-effect can play an important role in micellar systems. We further investigated the effectiveness of reactive counterion surfactants in decontaminating selected environmental solids that were spiked with 27 ppb fenitrothion. The solids were as follows: the clay mineral montmorillonite and SO-1 and S0-2 soils (obtained from the Canadian Certified Reference Materials Project). The reactive counterion surfactant solutions significantly enhanced the rate of fenitrothion degradation in the spiked solids over that obtained when the spiked solid was placed in contact with either 0.02 M KOH or water. The rate enhancements followed the order CTAOOH >> CTAMINA approximately CTAOH > KOH >> water. We conclude that reactive counterion surfactants, especially with alpha-nucleophiles, hold great potential in terms of remediating soils contaminated by toxic organophosphorus esters.
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Onyido I, Albright K, Buncel E. Catalysis of the ethanolysis of aryl methyl phenyl phosphinate esters by alkali metal ions: transition state structures for uncatalyzed and metal ion-catalyzed reactions. Org Biomol Chem 2005; 3:1468-75. [PMID: 15827643 DOI: 10.1039/b501537e] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper reports on a spectrophotometric kinetic study of the effects of the alkali metal ions Li+ and K+ on the ethanolysis of the aryl methyl phenyl phosphinate esters 3a-f in anhydrous ethanol at 25 degrees C. Rate data obtained in the absence and presence of complexing agents afford the second-order rate constants for the reaction of free ethoxide (k(EtO-)) and metal ion-ethoxide ion pairs (k(MOEt)). The sequence k(EtO-) < k(MOEt) is established for all the substrates, contrary to the generally observed reactivity order in nucleophilic substitution processes. The quantities deltaG(ip), deltaG(ts) and DeltaG(cat), which quantify the observed alkali metal ion effect in terms of transition state stabilization through chelation of the metal ion, give the order deltaG(ts) > deltaG(ip) for Li+ and K+. Hammett plots show significantly better correlation of rates with sigma and sigma(o) substituent constants than with sigma-, yielding moderately large rho(rho(o)) values that are consistent with a stepwise mechanism in which formation of a pentacoordinate (phosphorane) intermediate is the rate-limiting step. The range of the values of the selectivity parameter, rho(n) (= rho]/rho(eq)), 1.3-1.6, obtained for the uncatalyzed and alkali metal ion catalyzed reactions indicates that there is no significant perturbation of the transition state (TS) structure upon chelation of the metal ions. This finding is relevant to the mechanism of enzymatic phosphoryl transfer involving metal ion co-factors. The present results enable one to compare structural effects for nucleophilic reactions of several series of organophosphorus substrates. It is shown that the order of reactivity of the substrates: 4-nitrophenyl dimethyl phosphinate (2) > 3a > 4-nitrophenyl diphenyl phosphinate (1) is determined mainly by the steric effects of the alkyl/aryl substituents around the central P atom in the TS of the reaction.
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Affiliation(s)
- Ikenna Onyido
- Department of Chemistry and Center for Agrochemical Technology, University of Agriculture, Makurdi, Nigeria
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Balakrishnan VK, Han X, VanLoon GW, Dust JM, Toullec J, Buncel E. Acceleration of nucleophilic attack on an organophosphorothioate neurotoxin, fenitrothion, by reactive counterion cationic micelles. Regioselectivity as a probe of substrate orientation within the micelle. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:6586-6593. [PMID: 15274559 DOI: 10.1021/la049572d] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
31P NMR and UV-vis spectrometric evidence has revealed an unexpected regioselectivity in the reaction of fenitrothion, 1, an organophosphorus pesticide, with the cetyltrimethylammonium (CTA) surfactants CTAOH and CTAMINA, that incorporate the reactive counterions OH- and MINA- (the anti-pyruvaldehyde 1-oximate anion). While both micellar solutions accelerate decomposition of 1 compared to aqueous OH- alone, CTAMINA produced the largest rate enhancement (ca. 10(5)) at a pH (8.39) appropriate for environmental applications. In the absence of surfactant, reaction proceeds solely via the SN2(P) pathway. In the presence of surfactant but below the critical micelle concentration (cmc), a competitive SN2(C) pathway was observed in addition to SN2(P). Above the cmc, however, the CTAOH reaction again proceeded solely via the SN2(P) pathway while both pathways were operative with CTAMINA. The changes in reactivity and mechanistic pathway are discussed in terms of premicellar and micellar influences on rates and regioselectivity. A proposal that would account for the observed regioselectivity in the micellar system is that the aromatic ring and aliphatic side-chains of 1 are oriented toward the micellar interior, while the P=S moiety faces the aqueous pseudophase.
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Um IH, Lee HW, Park JY. Definitive evidence for a stepwise mechanism: a downward curvature in the plot of kobs versus amine concentrations in aminolysis reactions of dibenzo[1,2]oxathiin-6-oxide. Tetrahedron Lett 1999. [DOI: 10.1016/s0040-4039(99)01908-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Dušek L, Kaválek J, Štěrba V. Kinetics and mechanism of the reaction of substitutedO-benzoylbenzamidoximes with sodium methoxide in methanol. J PHYS ORG CHEM 1999. [DOI: 10.1002/(sici)1099-1395(199908)12:8<626::aid-poc173>3.0.co;2-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Burke SD, McDermott TS, O'Donnell CJ. Template Macrolactonization of Trichloroethyl Ester Derivatives Catalyzed by Potassium Salts. J Org Chem 1998; 63:2715-2718. [PMID: 11672142 DOI: 10.1021/jo970942v] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Steven D. Burke
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
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Plenio H, Burth D. Aminoferrocenes and Aminocobaltocenes as Redox-Active Chelating Ligands: Syntheses, Structures, and Coordination Chemistry1. Organometallics 1996. [DOI: 10.1021/om9602771] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Herbert Plenio
- Institut für Anorganische und Analytische Chemie, Albertstr. 21, 79104 Freiburg, Germany
| | - Dirk Burth
- Institut für Anorganische und Analytische Chemie, Albertstr. 21, 79104 Freiburg, Germany
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