Sodium nitroprusside (SNP) is a well-known vasodilator, which activates the cytosolic isozyme guanylate cyclase. It is quite stable by itself in aqueous solution and in the dark, but produces nitric oxide spontaneously under the appropriate reducing conditions. Both the neutral nitric oxide (NO) and the nitroxyl anion (NO m ) can be produced from SNP depending on the condition employed. NO release is favored at lower pH and cysteine concentration while NO m formation is more likely to occur at higher pH (>7) and cysteine concentration. NO was measured by electrochemical method and the chemical detection of NH 2 OH and NO 2 m are evidences of NO m formation. The mechanism of the reaction was found to be very complicated and involved three clear stages. NO and NO m are postulated to form in the first and third stages, respectively. All three stages showed cysteine dependence and were also affected by the pH of the solution. The first two stages resembled stepwise reversible two-electron reduction of NO + to...
{"title":"Mechanism of Nitric Oxide Release. I. Two-electron Reduction of Sodium Nitroprusside by l -cysteine in Aqueous Solution","authors":"James N. Smith, T. Dasgupta","doi":"10.1080/10286620210352","DOIUrl":"https://doi.org/10.1080/10286620210352","url":null,"abstract":"Sodium nitroprusside (SNP) is a well-known vasodilator, which activates the cytosolic isozyme guanylate cyclase. It is quite stable by itself in aqueous solution and in the dark, but produces nitric oxide spontaneously under the appropriate reducing conditions. Both the neutral nitric oxide (NO) and the nitroxyl anion (NO m ) can be produced from SNP depending on the condition employed. NO release is favored at lower pH and cysteine concentration while NO m formation is more likely to occur at higher pH (>7) and cysteine concentration. NO was measured by electrochemical method and the chemical detection of NH 2 OH and NO 2 m are evidences of NO m formation. The mechanism of the reaction was found to be very complicated and involved three clear stages. NO and NO m are postulated to form in the first and third stages, respectively. All three stages showed cysteine dependence and were also affected by the pH of the solution. The first two stages resembled stepwise reversible two-electron reduction of NO + to...","PeriodicalId":54977,"journal":{"name":"Inorganic Reaction Mechanisms","volume":"3 1","pages":"181-195"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59827656","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 : 2002-01-01DOI: 10.1080/10286620290034719
G. Brahma, P. Mohanty
The substitution reaction of potassium hexacyanoferrate(III) with hydroxopentaaquarhodium(III) has been studied spectrophotometrically as a function of pH, [substrate] and [Fe(CN) 6 3 m ] by following the absorption of Fe(III) substituted product at 355 nm. The rate of the reaction increases with the increase in [Fe(CN) 6 3 m ] but decreases with the increase in [H + ] and ionic strength of the medium. The activation parameters, j H # (36.5, 42.5) kJ mol m 1 and j S # ( m 191.0, m 133.0)J K m 1 mol m 1 for k S and k f paths respectively, have been calculated form the Eyring plots and were compared with the aqua exchange and analogous ligand substitution reactions. j G 0 , j H 0 and j S 0 for the outer-sphere association ( K OS ) path have been calculated, both from kinetic as well as the experimentally obtained equilibrium constant values. The mechanistic pathway for the substitution reaction within the outer-sphere complex is consistent with an associative interchange (Ia) type of phenomenon.
用分光光度法研究了六氰高铁酸钾(III)与羟基五氢四钠(III)的取代反应，考察了其与pH、[底物]和[Fe(CN) 63m]的关系。反应速率随[Fe(CN) 6.3 m]浓度的增加而增加，随[H +]浓度和介质离子强度的增加而降低。通过Eyring图计算了K - S和K - f路径的活化参数j H # (36.5, 42.5) kJ mol·m1和j S # (m 191.0, m 133.0) j K·m1·m1，并与水交换和类似的配体取代反应进行了比较。根据动力学和实验得到的平衡常数值，计算了外球缔合(kos)路径的jg0、jh0和js0。外球配合物内取代反应的机理途径符合结合交换(Ia)型现象。
{"title":"Kinetic and Mechanistic Studies of the Interaction of Hydroxopentaaquarhodium(III) Ion with Potassium Hexacyanoferrate(III)","authors":"G. Brahma, P. Mohanty","doi":"10.1080/10286620290034719","DOIUrl":"https://doi.org/10.1080/10286620290034719","url":null,"abstract":"The substitution reaction of potassium hexacyanoferrate(III) with hydroxopentaaquarhodium(III) has been studied spectrophotometrically as a function of pH, [substrate] and [Fe(CN) 6 3 m ] by following the absorption of Fe(III) substituted product at 355 nm. The rate of the reaction increases with the increase in [Fe(CN) 6 3 m ] but decreases with the increase in [H + ] and ionic strength of the medium. The activation parameters, j H # (36.5, 42.5) kJ mol m 1 and j S # ( m 191.0, m 133.0)J K m 1 mol m 1 for k S and k f paths respectively, have been calculated form the Eyring plots and were compared with the aqua exchange and analogous ligand substitution reactions. j G 0 , j H 0 and j S 0 for the outer-sphere association ( K OS ) path have been calculated, both from kinetic as well as the experimentally obtained equilibrium constant values. The mechanistic pathway for the substitution reaction within the outer-sphere complex is consistent with an associative interchange (Ia) type of phenomenon.","PeriodicalId":54977,"journal":{"name":"Inorganic Reaction Mechanisms","volume":"3 1","pages":"233-238"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59827721","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 : 2002-01-01DOI: 10.1080/1028662021000062563
S. Chimatadar, T. Basavaraj, S. Nandibewoor
The cerium(IV) oxidation of thallium(I) has been studied in an aqueous sulphuric acid medium. A minute amount (10 m 6 mol dm m 3 ) of ruthenium(III) is sufficient to catalyse the reaction. The reaction is first order in [cerium(IV)] in the presence of ruthenium(III) catalyst. The order in [thallium(I)] varies from zero to unity, whereas that in [ruthenium(III)] is unity. Increase in sulphuric acid concentration accelerates the reaction rate. The added products cerium(III) and thallium(III) do not significantly effect the reaction rate. The active catalyst, substrate and oxidant species are [Ru(H 2 O) 6 ] 3+ , Tl(SO 4 ) m and H 3 Ce( SO 4 ) 4 m , respectively. Possible mechanisms are proposed and the reaction constants involved have been determined.
研究了铈(IV)在硫酸水溶液中氧化铊(I)的反应。微量的钌(III) (10 m 6 mol dm m 3)就足以催化该反应。在钌(III)催化剂的存在下，反应在[铈(IV)]中一级进行。[铊(I)]中的顺序从零到单位不等，而[钌(III)]中的顺序是单位。硫酸浓度的增加使反应速率加快。添加产物铈(III)和铊(III)对反应速率影响不显著。活性催化剂为[Ru(h2o) 6] 3+，底物为Tl(so4) m，氧化剂为h3ce (so4) 4m。提出了可能的反应机理，并确定了反应常数。
{"title":"Ruthenium(III) Mediated Cerium(IV) Oxidation of Thallium(I) in Aqueous Sulphuric Acid--A Kinetic and Mechanistic Study","authors":"S. Chimatadar, T. Basavaraj, S. Nandibewoor","doi":"10.1080/1028662021000062563","DOIUrl":"https://doi.org/10.1080/1028662021000062563","url":null,"abstract":"The cerium(IV) oxidation of thallium(I) has been studied in an aqueous sulphuric acid medium. A minute amount (10 m 6 mol dm m 3 ) of ruthenium(III) is sufficient to catalyse the reaction. The reaction is first order in [cerium(IV)] in the presence of ruthenium(III) catalyst. The order in [thallium(I)] varies from zero to unity, whereas that in [ruthenium(III)] is unity. Increase in sulphuric acid concentration accelerates the reaction rate. The added products cerium(III) and thallium(III) do not significantly effect the reaction rate. The active catalyst, substrate and oxidant species are [Ru(H 2 O) 6 ] 3+ , Tl(SO 4 ) m and H 3 Ce( SO 4 ) 4 m , respectively. Possible mechanisms are proposed and the reaction constants involved have been determined.","PeriodicalId":54977,"journal":{"name":"Inorganic Reaction Mechanisms","volume":"4 1","pages":"209-219"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1028662021000062563","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59827805","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 : 2002-01-01DOI: 10.1080/1028662021000062617
Anju Agarwal, Gayatri Sharma, C. L. Khandelwal, P. Sharma
The kinetics of oxidation of mannitol by cerium(IV) in sulphuric acid medium have been studied. The spectral analysis of hydrazone derivative of the product indicates the product to be an aldehyde. The substrate forms an intermediate complex with the oxidant as is observed both kinetically and spectrophotometrically. Ce(SO 4 ) 2 has been considered to be the reactive sulphato-cerium(IV) species. The proposed mechanism corresponds to the rate law m d[Ce(IV)] d t = 2 kK [RCH 2 OH][Ce(IV)] (1+ K [RCH 2 OH])(1+ K 3 [ HSO 4 m ]) where R=CH 2 OH(CHOH) 4 . All the rate parameters have been evaluated.
研究了铈在硫酸介质中氧化甘露醇的动力学。该产物的腙衍生物的光谱分析表明该产物为醛。如动力学和分光光度法所观察到的，底物与氧化剂形成中间配合物。Ce(so4) 2被认为是反应性的硫铈(IV)物质。所提出的机理符合速率定律m d[Ce(IV)] d t = 2 kK [rch2 OH][Ce(IV)] (1+ K [rch2 OH])(1+ k3 [hso4 m])，其中R= ch2 OH(CHOH) 4。对所有速率参数进行了计算。
{"title":"Kinetics and Mechanism of Oxidation of Mannitol by Sulphato-cerium(IV) Species in Aqueous Acid Medium","authors":"Anju Agarwal, Gayatri Sharma, C. L. Khandelwal, P. Sharma","doi":"10.1080/1028662021000062617","DOIUrl":"https://doi.org/10.1080/1028662021000062617","url":null,"abstract":"The kinetics of oxidation of mannitol by cerium(IV) in sulphuric acid medium have been studied. The spectral analysis of hydrazone derivative of the product indicates the product to be an aldehyde. The substrate forms an intermediate complex with the oxidant as is observed both kinetically and spectrophotometrically. Ce(SO 4 ) 2 has been considered to be the reactive sulphato-cerium(IV) species. The proposed mechanism corresponds to the rate law m d[Ce(IV)] d t = 2 kK [RCH 2 OH][Ce(IV)] (1+ K [RCH 2 OH])(1+ K 3 [ HSO 4 m ]) where R=CH 2 OH(CHOH) 4 . All the rate parameters have been evaluated.","PeriodicalId":54977,"journal":{"name":"Inorganic Reaction Mechanisms","volume":"37 1","pages":"233-239"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1028662021000062617","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59827872","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 : 2002-01-01DOI: 10.1080/1028662021000062545
W. Jackson, Josephine A McKeon, W. Marty
The rates and steric course of base hydrolysis for v - cis - and trans -[Co(en) 2 (py)Cl] 2+ have been carefully determined. Values of k OH are 81 - 4 and 914 - 23 M m 1 s m 1 for the cis and trans ions respectively, and both are appreciably larger than their alkylamine analogues. Thus pyridine enhances the reactivity in base, but for these particular species the effect is no more cis or trans specific than it is for other "non-displaced" ligands. The steric course, 59% trans -product from trans -reactant, and 90% cis -product from cis -reactant, is likewise not unusual, but the net activity (8.3%) for the cis -product derived from v - or j - cis -reactant is anomalously low ( ca . 49% v , 41% j ). The results are discussed in terms of Nordmeyer's 1969 model which is reconsidered in the light of these and other new results.
{"title":"Kinetics and Stereochemistry of Base Hydrolysis of trans - and Λ- cis -[Co(en) 2 (py)Cl] 2+","authors":"W. Jackson, Josephine A McKeon, W. Marty","doi":"10.1080/1028662021000062545","DOIUrl":"https://doi.org/10.1080/1028662021000062545","url":null,"abstract":"The rates and steric course of base hydrolysis for v - cis - and trans -[Co(en) 2 (py)Cl] 2+ have been carefully determined. Values of k OH are 81 - 4 and 914 - 23 M m 1 s m 1 for the cis and trans ions respectively, and both are appreciably larger than their alkylamine analogues. Thus pyridine enhances the reactivity in base, but for these particular species the effect is no more cis or trans specific than it is for other \"non-displaced\" ligands. The steric course, 59% trans -product from trans -reactant, and 90% cis -product from cis -reactant, is likewise not unusual, but the net activity (8.3%) for the cis -product derived from v - or j - cis -reactant is anomalously low ( ca . 49% v , 41% j ). The results are discussed in terms of Nordmeyer's 1969 model which is reconsidered in the light of these and other new results.","PeriodicalId":54977,"journal":{"name":"Inorganic Reaction Mechanisms","volume":"4 1","pages":"125-132"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59827293","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 : 2002-01-01DOI: 10.1080/1028662021000062473
A. Siddalingaiah, S. Naik
New complexes of Co(II), Ni(II) and Cu(II) with di(3-chloro-4-methylphenyl) carbazone having the general formula [M(DCMPC) 2 ] [where M=Co(II), Ni(II) or Cu(II); DCMPC=di(3-chloro-4-methylphenyl)carbazone] have been synthesized and characterized by elemental analyses, magnetic moment measurements, Uv-Vis., IR, EPR and thermal studies. The DCMPC behaves as a bidentate monoanionic ligand coordinating through the ketonic oxygen and azo nitrogen. The interpretation, mathematical analyses of the thermoanalytical data (TG and DTA) and evaluation of kinetic parameters are presented in this communication. The energy of activation for the two clear-cut steps of decomposition for all the complexes are compared by employing the Freeman-Carroll equation, the integration method using the Coats-Redfern equation and the approximation method using the Horowitz-Metzger equation. The Coats-Redfern equation was extended to evaluate other kinetic parameters such as pre-exponential factor and entropy of activation.
Co(II)、Ni(II)和Cu(II)与二(3-氯-4-甲基苯基)咔唑酮的新配合物，其通式为[M(DCMPC) 2][其中M=Co(II)、Ni(II)或Cu(II);合成了二(3-氯-4-甲基苯基)咔唑[DCMPC]，并用元素分析、磁矩测量、紫外-可见等方法对其进行了表征。， IR, EPR和热研究。DCMPC表现为双齿单阴离子配体，通过酮氧和偶氮配位。本文介绍了热分析数据(TG和DTA)的解释、数学分析和动力学参数的评价。采用Freeman-Carroll方程、Coats-Redfern方程的积分法和Horowitz-Metzger方程的近似法对所有配合物的两个明确分解步骤的活化能进行了比较。将Coats-Redfern方程推广到其他动力学参数，如指数前因子和激活熵。
{"title":"Thermo-kinetic and Spectral Studies of Cobalt(II), Nickel(II) and Copper(II) Complexes With Di(3-chloro-4-methylphenyl)carbazone","authors":"A. Siddalingaiah, S. Naik","doi":"10.1080/1028662021000062473","DOIUrl":"https://doi.org/10.1080/1028662021000062473","url":null,"abstract":"New complexes of Co(II), Ni(II) and Cu(II) with di(3-chloro-4-methylphenyl) carbazone having the general formula [M(DCMPC) 2 ] [where M=Co(II), Ni(II) or Cu(II); DCMPC=di(3-chloro-4-methylphenyl)carbazone] have been synthesized and characterized by elemental analyses, magnetic moment measurements, Uv-Vis., IR, EPR and thermal studies. The DCMPC behaves as a bidentate monoanionic ligand coordinating through the ketonic oxygen and azo nitrogen. The interpretation, mathematical analyses of the thermoanalytical data (TG and DTA) and evaluation of kinetic parameters are presented in this communication. The energy of activation for the two clear-cut steps of decomposition for all the complexes are compared by employing the Freeman-Carroll equation, the integration method using the Coats-Redfern equation and the approximation method using the Horowitz-Metzger equation. The Coats-Redfern equation was extended to evaluate other kinetic parameters such as pre-exponential factor and entropy of activation.","PeriodicalId":54977,"journal":{"name":"Inorganic Reaction Mechanisms","volume":"4 1","pages":"89-93"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59827407","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 : 2002-01-01DOI: 10.1080/1028662021000062482
S. Ahmad, A. Isab, M. Wazeer
Exchange reactions of gold(I) thiomalate (AuStm) n with two diselenides (RSe-SeR), selenocystine and selenocystamine have been studied in D 2 O by 13 C NMR spectroscopy. Upon interaction of diselenides with (AuStm) n , the Se-Se bond is broken, resulting in the formation of RSe-Stm and (AuSeR) n species. RSe-Stm on further decomposition leads to the formation of thiomalic disufide (Stm) 2 . The second order rate constant was determined for the decomposition of RSe-Stm species and is found to be 3.21 2 10 m 4 l mol m 1 s m 1 . The intensity of thiomalic disulfide resonances increases, while the intensity of RSe-Stm resonances decreases with time. The end result of both reactions is the formation of (Stm) 2 and the deposition of metallic gold and brown ppts. In both cases exchange takes place immediately, however, the overall reaction of (AuStm) n with selenocystamine was faster than with selenocystine.
用13c NMR研究了硫代酸金(I)与硒半胱氨酸和硒半胺两种二硒化物(se - ser)在d2o中的交换反应。二硒化物与(AuStm) n相互作用后，Se-Se键断裂，形成RSe-Stm和(AuSeR) n。RSe-Stm进一步分解生成二硫化硫(Stm) 2。测定了RSe-Stm的二级分解速率常数为3.21 2 10 m 4 l mol m 1 s m 1。硫柳二硫的共振强度随时间增加而增加，而RSe-Stm的共振强度随时间减少。这两种反应的最终结果是(Stm) 2的形成和金属金和棕色铂的沉积。在这两种情况下，交换都立即发生，但(AuStm) n与硒半胺的整体反应比与硒半胺的反应快。
{"title":"13 C NMR Studies of the Redox and Exchange Reactions of Gold(I) Thiomalate with Diselenides","authors":"S. Ahmad, A. Isab, M. Wazeer","doi":"10.1080/1028662021000062482","DOIUrl":"https://doi.org/10.1080/1028662021000062482","url":null,"abstract":"Exchange reactions of gold(I) thiomalate (AuStm) n with two diselenides (RSe-SeR), selenocystine and selenocystamine have been studied in D 2 O by 13 C NMR spectroscopy. Upon interaction of diselenides with (AuStm) n , the Se-Se bond is broken, resulting in the formation of RSe-Stm and (AuSeR) n species. RSe-Stm on further decomposition leads to the formation of thiomalic disufide (Stm) 2 . The second order rate constant was determined for the decomposition of RSe-Stm species and is found to be 3.21 2 10 m 4 l mol m 1 s m 1 . The intensity of thiomalic disulfide resonances increases, while the intensity of RSe-Stm resonances decreases with time. The end result of both reactions is the formation of (Stm) 2 and the deposition of metallic gold and brown ppts. In both cases exchange takes place immediately, however, the overall reaction of (AuStm) n with selenocystamine was faster than with selenocystine.","PeriodicalId":54977,"journal":{"name":"Inorganic Reaction Mechanisms","volume":"4 1","pages":"95-102"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1028662021000062482","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59827491","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}
Conventional and stopped-flow spectrophotometry was used to study the kinetics of ligand substitution in a number of mono g -diketone salen iron(III) complexes, [Fe(salen)(O 7 O)], by 8-hydroxyquinoline (=HO 7 N) in alcohol media (O 7 O m =anion of the g -diketones pentane-2,4-dione, 2,6-dimethylheptane-3,5-dione, 2,2,6,6-tetramethylheptane-3,5-dione, 1-phenylbutane-1,3-dione, 1,3-diphenylpropane-1,3-dione, and 1-(2-thienyl)-4,4,4-trifluorobutane-1,3-dione; salen=anion of N , N '-disalicylideneethylenediamine). As shown by spectrophotometry and conductometry, the solutions of complexes [Fe(salen)(O 7 O)] in alcohols ROH are subject to solvolytic dissociation, leading to neutral and charged solvento species [Fe(salen)S 2 ] (S=RO m and ROH, respectively). The dissociation constants K D for the systems [Fe(salen)(O 7 O)]/ROH, as determined by concentration-jump experiments as well as by dilution experiments, range from 3 2 10 m 5 M to 1 2 10 m 3 M. The reaction of complexes [Fe(salen)(O 7 O)] with HO 7 N in ...
常规和stopped-flow分光光度法用于研究配体的动力学替换的mono g二酮萨伦铁(III)复合物,(Fe(伦)(O 7 O)], 8 -羟基喹啉(= HO 7 N)在酒精通过媒体(O 7 O m =阴离子的g -diketones pentane-2, 4-dione, 2, 6-dimethylheptane-3, 5-dione, 2, 2, 6日6-tetramethylheptane-3, 5-dione, 1-phenylbutane-1, 3-dione, 1, 3-diphenylpropane-1, 3-dione, 1 - (2-thienyl) 4, 4, 4-trifluorobutane-1, 3-dione;salen= N, N '-二二烷基乙二胺的阴离子。分光光度法和电导法表明，配合物[Fe(salen)(O 7 O)]在醇类ROH中的溶液发生溶剂解离，产生中性和带电溶剂[Fe(salen) s2] (S=RO m和ROH)。通过浓度跳变实验和稀释实验确定了体系[Fe(salen)(o7 O)]/ROH的解离常数K D的范围为3 2 10 m 5 m ~ 1 2 10 m 3 m。
{"title":"Kinetics and Mechanism of Ligand Substitution in Octahedral Salen Complexes of Iron(III) in Alcohol Media: Solvolysis and Intermediate Ligand Rearrangement Controlling the Substitution Process","authors":"Gerhard Gumbel, H. Elias","doi":"10.1080/10286620213670","DOIUrl":"https://doi.org/10.1080/10286620213670","url":null,"abstract":"Conventional and stopped-flow spectrophotometry was used to study the kinetics of ligand substitution in a number of mono g -diketone salen iron(III) complexes, [Fe(salen)(O 7 O)], by 8-hydroxyquinoline (=HO 7 N) in alcohol media (O 7 O m =anion of the g -diketones pentane-2,4-dione, 2,6-dimethylheptane-3,5-dione, 2,2,6,6-tetramethylheptane-3,5-dione, 1-phenylbutane-1,3-dione, 1,3-diphenylpropane-1,3-dione, and 1-(2-thienyl)-4,4,4-trifluorobutane-1,3-dione; salen=anion of N , N '-disalicylideneethylenediamine). As shown by spectrophotometry and conductometry, the solutions of complexes [Fe(salen)(O 7 O)] in alcohols ROH are subject to solvolytic dissociation, leading to neutral and charged solvento species [Fe(salen)S 2 ] (S=RO m and ROH, respectively). The dissociation constants K D for the systems [Fe(salen)(O 7 O)]/ROH, as determined by concentration-jump experiments as well as by dilution experiments, range from 3 2 10 m 5 M to 1 2 10 m 3 M. The reaction of complexes [Fe(salen)(O 7 O)] with HO 7 N in ...","PeriodicalId":54977,"journal":{"name":"Inorganic Reaction Mechanisms","volume":"3 1","pages":"221-232"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59827712","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 : 2002-01-01DOI: 10.1080/1028662021000062626
D. Fairlie, B. Dutton, Josephine A McKeon, W. Jackson
The synthesis and properties of [(NH 3 ) 5 CoOSO 2 Cl](ClO 4 ) 2 are described. This complex is one of the most reactive cobalt(III) species ever isolated ( t 1/2 10 s; 25°C; 0.1 M HClO 4 ). In water it yields [(NH 3 ) 5 CoOSO 3 ] + , [(NH 3 ) 5 CoOH 2 ] 3+ and [(NH 3 ) 5 CoCl] 2+ . The first two of these products come from the expected direct S-Cl and Co-O cleavages. The chloro complex arises via intramolecular linkage isomerisation to the transient [(NH 3 ) 5 Co-ClSO 3 ] 2+ species which then cleaves the S-Cl bond. Considerable attention is given to the characterisation of the Co-O 3 SCl species, including reaction in 17 O-H 2 O where the NMR spectra confirm Co- 17 OSO 3 , Co- 17 OH 2 and free 17 OSO 3 2 m products. The reactions have been studied also in aqueous base, 0.1 M HClO 4 and Me 2 SO where the same reactions are observed but in quite different proportions. In liquid ammonia, with or without added NH 4 + , no O-bonded sulphamate complex [(NH 3 ) 5 CoOSO 2 NH 2 ] 2+ arising from direct S-Cl clea...
{"title":"Deactivation of the chlorosulfonate ion coordinated to pentaamminecobalt(III)","authors":"D. Fairlie, B. Dutton, Josephine A McKeon, W. Jackson","doi":"10.1080/1028662021000062626","DOIUrl":"https://doi.org/10.1080/1028662021000062626","url":null,"abstract":"The synthesis and properties of [(NH 3 ) 5 CoOSO 2 Cl](ClO 4 ) 2 are described. This complex is one of the most reactive cobalt(III) species ever isolated ( t 1/2 10 s; 25°C; 0.1 M HClO 4 ). In water it yields [(NH 3 ) 5 CoOSO 3 ] + , [(NH 3 ) 5 CoOH 2 ] 3+ and [(NH 3 ) 5 CoCl] 2+ . The first two of these products come from the expected direct S-Cl and Co-O cleavages. The chloro complex arises via intramolecular linkage isomerisation to the transient [(NH 3 ) 5 Co-ClSO 3 ] 2+ species which then cleaves the S-Cl bond. Considerable attention is given to the characterisation of the Co-O 3 SCl species, including reaction in 17 O-H 2 O where the NMR spectra confirm Co- 17 OSO 3 , Co- 17 OH 2 and free 17 OSO 3 2 m products. The reactions have been studied also in aqueous base, 0.1 M HClO 4 and Me 2 SO where the same reactions are observed but in quite different proportions. In liquid ammonia, with or without added NH 4 + , no O-bonded sulphamate complex [(NH 3 ) 5 CoOSO 2 NH 2 ] 2+ arising from direct S-Cl clea...","PeriodicalId":54977,"journal":{"name":"Inorganic Reaction Mechanisms","volume":"4 1","pages":"197-208"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59827916","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}
N -bromosuccinimide oxidation of manganate(VI) was studied spectrophotometrically. The reaction showed first order kinetics in [ MnO 4 2 m ] and an apparent less than unit order dependence in [NBS] and rate of reaction decreases with increase in [alkali]. Initial addition of products had no significant effect on the rate of the reaction. The effect of ionic strength and dielectric constant of the reaction medium have been investigated. The results suggest that the reaction proceeds via formation of a complex between active species of oxidant and MnO 4 2 m , which subsequently decomposes in a rate determining step followed by a fast step to yield the products. A mechanism involving the HOBr as the reactive species of the oxidant has been proposed. The reaction constants involved in the mechanism have been computed. There is a good agreement between the observed and calculated rate constants under different experimental conditions. The activation parameters were calculated with respect to the slow step of t...
{"title":"Conversion of Manganate(VI) to Manganate(VII) By N -bromosuccinimide in Aqueous Alkaline Medium: A Kinetic and Mechanistic Approach","authors":"C. P. Kathari, P. D. Pol, S. Nandibewoor","doi":"10.1080/713931737","DOIUrl":"https://doi.org/10.1080/713931737","url":null,"abstract":"N -bromosuccinimide oxidation of manganate(VI) was studied spectrophotometrically. The reaction showed first order kinetics in [ MnO 4 2 m ] and an apparent less than unit order dependence in [NBS] and rate of reaction decreases with increase in [alkali]. Initial addition of products had no significant effect on the rate of the reaction. The effect of ionic strength and dielectric constant of the reaction medium have been investigated. The results suggest that the reaction proceeds via formation of a complex between active species of oxidant and MnO 4 2 m , which subsequently decomposes in a rate determining step followed by a fast step to yield the products. A mechanism involving the HOBr as the reactive species of the oxidant has been proposed. The reaction constants involved in the mechanism have been computed. There is a good agreement between the observed and calculated rate constants under different experimental conditions. The activation parameters were calculated with respect to the slow step of t...","PeriodicalId":54977,"journal":{"name":"Inorganic Reaction Mechanisms","volume":"3 1","pages":"213-220"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/713931737","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60390085","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：