Pub Date : 2004-01-01DOI: 10.1515/IRM.2004.5.2.109
A. Isab, C. Shaw III, A. Muñoz, J. Hoeschele
{"title":"Exchange Reactions between Albumin-Au(I)-PEt3 Complex and Me3PAuCl or iPr3PAuCl: 31P NMR Spectroscopic Studies","authors":"A. Isab, C. Shaw III, A. Muñoz, J. Hoeschele","doi":"10.1515/IRM.2004.5.2.109","DOIUrl":"https://doi.org/10.1515/IRM.2004.5.2.109","url":null,"abstract":"","PeriodicalId":8996,"journal":{"name":"BioInorganic Reaction Mechanisms","volume":"110 1","pages":"109 - 116"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73507250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-01-01DOI: 10.1515/IRM.2004.5.2.117
M. P. Dahal, G. Lawrance
The nonamolybdomanganate ion (as (NH4)6[MnMo9O32].6H2O) is a water-soluble manganese(IV) oxidant which is stable in the pH range 3.0 – 5.0, and oxidises iodide, sulfite and oxalate anions in solution. The kinetics of the iodide oxidation display autocatalytic behaviour, associated with catalysis by low-valent manganese ion formed in the reaction. A pH dependence is associated with protonation equilibria of the cluster and or pH-dependent dissociation reactions of the cluster. Sulfite and oxalate oxidation proceeds via more complex multi-step pathways, but do not require inclusion of autocatalysis in the kinetic analysis.
{"title":"Oxidation of Iodide and Other Inorganic Ions Employing Nonamolybdomanganate Ion ([MnMo9O32]6-) as Oxidant","authors":"M. P. Dahal, G. Lawrance","doi":"10.1515/IRM.2004.5.2.117","DOIUrl":"https://doi.org/10.1515/IRM.2004.5.2.117","url":null,"abstract":"The nonamolybdomanganate ion (as (NH4)6[MnMo9O32].6H2O) is a water-soluble manganese(IV) oxidant which is stable in the pH range 3.0 – 5.0, and oxidises iodide, sulfite and oxalate anions in solution. The kinetics of the iodide oxidation display autocatalytic behaviour, associated with catalysis by low-valent manganese ion formed in the reaction. A pH dependence is associated with protonation equilibria of the cluster and or pH-dependent dissociation reactions of the cluster. Sulfite and oxalate oxidation proceeds via more complex multi-step pathways, but do not require inclusion of autocatalysis in the kinetic analysis.","PeriodicalId":8996,"journal":{"name":"BioInorganic Reaction Mechanisms","volume":"20 1","pages":"117 - 124"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90536118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-01-01DOI: 10.1515/IRM.2004.5.2.125
H. Ewais, Samah A. Ahmed, A. ABDEL-KHALEK,
{"title":"Kinetics and Mechanism of Oxidation of Chromium(III)-Guanosine Complex By Periodate","authors":"H. Ewais, Samah A. Ahmed, A. ABDEL-KHALEK,","doi":"10.1515/IRM.2004.5.2.125","DOIUrl":"https://doi.org/10.1515/IRM.2004.5.2.125","url":null,"abstract":"","PeriodicalId":8996,"journal":{"name":"BioInorganic Reaction Mechanisms","volume":"32 1","pages":"125 - 133"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77939468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
TThe radiolysis of water in the presence of complexes of Pt with amines and iodine acting as catalysts of the hydrogen production is reported. A radionuclide of 60Co with an activity of about 5x104 Ci was employed as an irradiation g source. A considerable increase of the amount of hydrogen resulting from the radiolysis of water in the presence of the above mentioned complex combinations was noticed in comparison with the reference sample, irradiated under the same experimental conditions, but without any catalyst. The products have been identified by means of a method based on mass spectrometry. A mechanism for the catalysed reaction is proposed.
{"title":"Use of Some Complexes of Platinum in the Radiolytic Decomposition of Water","authors":"M. Goanta, A. Cecal","doi":"10.1515/IRM.2004.5.2.97","DOIUrl":"https://doi.org/10.1515/IRM.2004.5.2.97","url":null,"abstract":"TThe radiolysis of water in the presence of complexes of Pt with amines and iodine acting as catalysts of the hydrogen production is reported. A radionuclide of 60Co with an activity of about 5x104 Ci was employed as an irradiation g source. A considerable increase of the amount of hydrogen resulting from the radiolysis of water in the presence of the above mentioned complex combinations was noticed in comparison with the reference sample, irradiated under the same experimental conditions, but without any catalyst. The products have been identified by means of a method based on mass spectrometry. A mechanism for the catalysed reaction is proposed.","PeriodicalId":8996,"journal":{"name":"BioInorganic Reaction Mechanisms","volume":"155 1","pages":"100 - 97"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77028204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-01-01DOI: 10.1515/IRM.2004.5.2.101
L. Carvalho, María V. Alipázaga, W. Crivelente, N. Coichev
The oxidation of Co(II)/2-amino-2-hydroxymethyl-1,3-propanediol (TRIS) by dissolved oxygen is accelerated by S(IV) oxides (SO3 and HSO3-). The effectiveness of this autocatalytic process is controlled by S(IV), manganese(II) and oxygen concentrations. The synergistic effect of Mn(II) is clearly evaluated and depends on the medium acidity and TRIS concentration, it must be related to the speciation of Co(II)/Co(III) and Mn(II)/Mn(III) complexes and the S(IV) species that participate in the rate determining step. The metal ions in the trivalent oxidation state react with S(IV) to initiate a radical chain reaction in which S(IV) is oxidized to sulfate and the metal ion is reduced to the divalent state.
{"title":"The Autoxidation of Co(II)/2-Aamino- 2-Hydroxymethyl-1,3-Propanediol in the Presence of Mn(II) and S(IV)","authors":"L. Carvalho, María V. Alipázaga, W. Crivelente, N. Coichev","doi":"10.1515/IRM.2004.5.2.101","DOIUrl":"https://doi.org/10.1515/IRM.2004.5.2.101","url":null,"abstract":"The oxidation of Co(II)/2-amino-2-hydroxymethyl-1,3-propanediol (TRIS) by dissolved oxygen is accelerated by S(IV) oxides (SO3 and HSO3-). The effectiveness of this autocatalytic process is controlled by S(IV), manganese(II) and oxygen concentrations. The synergistic effect of Mn(II) is clearly evaluated and depends on the medium acidity and TRIS concentration, it must be related to the speciation of Co(II)/Co(III) and Mn(II)/Mn(III) complexes and the S(IV) species that participate in the rate determining step. The metal ions in the trivalent oxidation state react with S(IV) to initiate a radical chain reaction in which S(IV) is oxidized to sulfate and the metal ion is reduced to the divalent state.","PeriodicalId":8996,"journal":{"name":"BioInorganic Reaction Mechanisms","volume":"3 1","pages":"101 - 108"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80819190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reaction of [(H2O)(tap)2RuORu(tap)2(OH2)](1) with adenosine has been examined spectrophotometrically in aqueous medium as a function of [complex ion], [ligand], pH and temperature at constant ionic strength. At the physiological pH (7.4), (1) shows two consecutive steps; both of which are [ligand] dependent. The activation parameters from Eyring plots are: ∆H1 = 9.0 + _ 0.4 kJ mol-1, ∆S1 = -266 + _ 2 J K-1mol-1, ∆H2 = 35.6 + _ 2.2 kJ mol-1 and ∆S2 = -212 + _ 7 JK-1 mol-1. Available kinetic and activation parameters are in consonance with an associative interchange mechanism. From the temperature dependence of the outersphere association equilibrium constant the thermodynamic parameters calculated are: ∆H1 = 25.8 + _ 1.0 kJ mol-1, ∆S1 = 126 + _ 3 J K-1mol-1 and ∆H2 = 19.7 + _ 6.1 kJ mol-1, ∆S2 = 108 + _19 J K-1 mol-1, a negative ∆Go value at all temperatures studied supports spontaneous formation of an outersphere association complex.
{"title":"Interaction of Adenosine with[(H2O)- (tap)2RuORu(tap)2(H2O)]2+ Ion in Aqueous Medium: Kinetic and Mechanistic Studies","authors":"Hriday Chattopadhyay, A. K. Ghosh, B. Ghosh","doi":"10.1515/IRM.2004.5.2.87","DOIUrl":"https://doi.org/10.1515/IRM.2004.5.2.87","url":null,"abstract":"Reaction of [(H2O)(tap)2RuORu(tap)2(OH2)](1) with adenosine has been examined spectrophotometrically in aqueous medium as a function of [complex ion], [ligand], pH and temperature at constant ionic strength. At the physiological pH (7.4), (1) shows two consecutive steps; both of which are [ligand] dependent. The activation parameters from Eyring plots are: ∆H1 = 9.0 + _ 0.4 kJ mol-1, ∆S1 = -266 + _ 2 J K-1mol-1, ∆H2 = 35.6 + _ 2.2 kJ mol-1 and ∆S2 = -212 + _ 7 JK-1 mol-1. Available kinetic and activation parameters are in consonance with an associative interchange mechanism. From the temperature dependence of the outersphere association equilibrium constant the thermodynamic parameters calculated are: ∆H1 = 25.8 + _ 1.0 kJ mol-1, ∆S1 = 126 + _ 3 J K-1mol-1 and ∆H2 = 19.7 + _ 6.1 kJ mol-1, ∆S2 = 108 + _19 J K-1 mol-1, a negative ∆Go value at all temperatures studied supports spontaneous formation of an outersphere association complex.","PeriodicalId":8996,"journal":{"name":"BioInorganic Reaction Mechanisms","volume":"10 1","pages":"87 - 96"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80041970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yessenia Ocasio-Delgadof, Luis A. Rivera-Riveraf, Gisela Crespo-Romanf, J. E. Cortés-Figueroa
Abstract Piperidine (pip) displaces l,2-bis(diphenylphosphino)ethane (dppe) from mer-(η2-C60)(η2-dppe)W(CO)3 to produce mer*-(η2-C60)(η1-ρίρ)2ν(ΟΟ)3. The reactions are first order and second order with respect to the molar concentrations of m£r-(r|2-C60)(r|2-dppe)W(CO)3 and pip, respectively. The proposed mechanism, based on the rate law and on the activation parameters, involves an initial pip-assisted ringopening of the dppe ligand to produce the electronically-saturated intermediate fac (η2-C60)(η'-ρίρ) (n1-dppe)W(CO)3. This mechanism differs from previously proposed mechanisms for the ligand exchange reactions of closely-related complexes such as/fac-(η1-L)(η2-dppe)W(CO)3 (L = CO, piperidine, pyridine) and is contrary to the known cis labilizing property of dppe. These results suggest that [60]fullerene has a strong steric influence on the inorganic moiety of the complex and on its chemical behavior.
{"title":"Site of Bond Breaking in mer-(Dihapto-[60]fullerene) (Dihapto-1,2-Bis-(DiphenyIphosphino)ethane Tricarbonyl Tungsten(0)","authors":"Yessenia Ocasio-Delgadof, Luis A. Rivera-Riveraf, Gisela Crespo-Romanf, J. E. Cortés-Figueroa","doi":"10.1515/irm-2003-0102","DOIUrl":"https://doi.org/10.1515/irm-2003-0102","url":null,"abstract":"Abstract Piperidine (pip) displaces l,2-bis(diphenylphosphino)ethane (dppe) from mer-(η2-C60)(η2-dppe)W(CO)3 to produce mer*-(η2-C60)(η1-ρίρ)2ν(ΟΟ)3. The reactions are first order and second order with respect to the molar concentrations of m£r-(r|2-C60)(r|2-dppe)W(CO)3 and pip, respectively. The proposed mechanism, based on the rate law and on the activation parameters, involves an initial pip-assisted ringopening of the dppe ligand to produce the electronically-saturated intermediate fac (η2-C60)(η'-ρίρ) (n1-dppe)W(CO)3. This mechanism differs from previously proposed mechanisms for the ligand exchange reactions of closely-related complexes such as/fac-(η1-L)(η2-dppe)W(CO)3 (L = CO, piperidine, pyridine) and is contrary to the known cis labilizing property of dppe. These results suggest that [60]fullerene has a strong steric influence on the inorganic moiety of the complex and on its chemical behavior.","PeriodicalId":8996,"journal":{"name":"BioInorganic Reaction Mechanisms","volume":"88 1","pages":"13 - 20"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76667229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The kinetics of the title reaction have been investigated in both aqueous and micellar cetyltrimethylammonium bromide(CTAB) solutions. Rate data indicate that the reaction follows the template mechanism in both the media. The observed rate constant is affected by [CTAB] changes and the maximum rate enhancement is ca. 4 -fold. The following parameters have been calculated at pH 5.0: for aqueous, kobs = 5.6 χ 10-5 s-1, ΔH* = 61 k J mol-1, ΔS* = -122 J K-1mol-1 ; for CTAB , kΨ = 24.7 χ 10-5 s-1 , ΔH* = 35 k J mol-1, ΔS* = -200 J K-1 mol-1, which reveal CTAB behaving as a catalyst. To explain the dependence of the reaction rate on [CTAB], pseudo-phase model proposed by Menger and Portnoy and modified by Bunton and Rodenas was used. The catalytic role of CTAB can be related to the extent of incorporation or association of the chromium(III)-tryptophan and ninhydrin into the micelles. Various factors which affect km, Ks KN and are discussed taking into account the micellar surface solvent properties.
{"title":"Kinetics and Mechanism of the Reaction of Ninhydrin with Chromium(III)-tryptophan Complex in Absence and Presence of Surfactants","authors":"Kabir-ud-din, M. Akram, Z. Khan","doi":"10.1515/irm-2003-0101","DOIUrl":"https://doi.org/10.1515/irm-2003-0101","url":null,"abstract":"Abstract The kinetics of the title reaction have been investigated in both aqueous and micellar cetyltrimethylammonium bromide(CTAB) solutions. Rate data indicate that the reaction follows the template mechanism in both the media. The observed rate constant is affected by [CTAB] changes and the maximum rate enhancement is ca. 4 -fold. The following parameters have been calculated at pH 5.0: for aqueous, kobs = 5.6 χ 10-5 s-1, ΔH* = 61 k J mol-1, ΔS* = -122 J K-1mol-1 ; for CTAB , kΨ = 24.7 χ 10-5 s-1 , ΔH* = 35 k J mol-1, ΔS* = -200 J K-1 mol-1, which reveal CTAB behaving as a catalyst. To explain the dependence of the reaction rate on [CTAB], pseudo-phase model proposed by Menger and Portnoy and modified by Bunton and Rodenas was used. The catalytic role of CTAB can be related to the extent of incorporation or association of the chromium(III)-tryptophan and ninhydrin into the micelles. Various factors which affect km, Ks KN and are discussed taking into account the micellar surface solvent properties.","PeriodicalId":8996,"journal":{"name":"BioInorganic Reaction Mechanisms","volume":"50 1","pages":"1 - 12"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88475448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Kinetic what-if simulations can be important for both the optimisation of an industrial process as well as the design of future experiments in the evolving process of a detailed kinetic analysis on laboratory scale. From our viewpoint as coordination chemists we present SIMKIN, a tool for an easy intuitive and fast simulation of chemical kinetics. As one of the key features, an intelligent model parser translates conventional chemical equations consisting of virtually any reaction steps including feedbacks into the rate law. The corresponding differential equations are then solved by standard routines for numerical integration, and the concentration profiles of the involved species plotted versus the reaction time. By means of selected kinetic examples of increasing complexity taken from coordination chemistry we demonstrate the capabilities and versatility of the program. A MATLAB® version with a complete graphical user interface can be requested from the authors free of charge.
{"title":"Simulation of Complex Chemical Kinetics","authors":"R. Dyson, M. Maeder, G. Puxty, Y. Neuhold","doi":"10.1515/irm-2003-0105","DOIUrl":"https://doi.org/10.1515/irm-2003-0105","url":null,"abstract":"Abstract Kinetic what-if simulations can be important for both the optimisation of an industrial process as well as the design of future experiments in the evolving process of a detailed kinetic analysis on laboratory scale. From our viewpoint as coordination chemists we present SIMKIN, a tool for an easy intuitive and fast simulation of chemical kinetics. As one of the key features, an intelligent model parser translates conventional chemical equations consisting of virtually any reaction steps including feedbacks into the rate law. The corresponding differential equations are then solved by standard routines for numerical integration, and the concentration profiles of the involved species plotted versus the reaction time. By means of selected kinetic examples of increasing complexity taken from coordination chemistry we demonstrate the capabilities and versatility of the program. A MATLAB® version with a complete graphical user interface can be requested from the authors free of charge.","PeriodicalId":8996,"journal":{"name":"BioInorganic Reaction Mechanisms","volume":"1 1","pages":"39 - 46"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88924488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Using a range of substituted 2,2':6',2"-terpyridine ligands, the effects of π-stacking on the rates of formation of bis(terpyridine)nickel(II) complexes have been investigated in 70:30 v/v % methanol:water. Compared with the rates of formation of the mono(terpyridine)nickel(II) complexes, for the bis(terpyridine)nickel(II) complexes at 25°C, rate enhancements in the range 11-146 were found. For unsubstituted 2,2':6',2"-terpyridine studied in the same solvent mixture, the rate enhancement at 25°C is 11, whereas for 4'-(2-naphthyl)-2,2':6',2"-terpyridine the rate enhancement is 146.
{"title":"Kinetic and mechanistic studies of mono(terpyridine)- to bis(terpyridine)-nickel(II) complex formation reactions involving a range of substituted 2,2′:6′,2″-terpyridine ligands: an investigation of π-stacking interactions in outer-sphere complexes.","authors":"Gleb U. Priimov, P. Moore","doi":"10.1515/irm-2003-0103","DOIUrl":"https://doi.org/10.1515/irm-2003-0103","url":null,"abstract":"Abstract Using a range of substituted 2,2':6',2\"-terpyridine ligands, the effects of π-stacking on the rates of formation of bis(terpyridine)nickel(II) complexes have been investigated in 70:30 v/v % methanol:water. Compared with the rates of formation of the mono(terpyridine)nickel(II) complexes, for the bis(terpyridine)nickel(II) complexes at 25°C, rate enhancements in the range 11-146 were found. For unsubstituted 2,2':6',2\"-terpyridine studied in the same solvent mixture, the rate enhancement at 25°C is 11, whereas for 4'-(2-naphthyl)-2,2':6',2\"-terpyridine the rate enhancement is 146.","PeriodicalId":8996,"journal":{"name":"BioInorganic Reaction Mechanisms","volume":"121 1","pages":"21 - 30"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73761619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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