Activation parameters of solvent exchange and ligand substitution reactions of metal ions are discussed in relation to structural properties. Solvent exchange is treated as a particular case of ligand substitution. A general relation between enthalpy and entropy of activation is shown to hold for both types of reaction at divalent metal ions for a wide variety of solvents and ligands, after corrections have been made for ligand-field stabilisation. Water occupies a middle position in the range of solvents. The results are interpreted in terms of a structural model for a solvated ion in solution, based on that of Frank and Wen.
{"title":"Kinetics of solvent exchange and ligand substitution reactions of metal ions in relation to structural properties of the solvent","authors":"H. P. Bennetto, E. Caldin","doi":"10.1039/J19710002198","DOIUrl":"https://doi.org/10.1039/J19710002198","url":null,"abstract":"Activation parameters of solvent exchange and ligand substitution reactions of metal ions are discussed in relation to structural properties. Solvent exchange is treated as a particular case of ligand substitution. A general relation between enthalpy and entropy of activation is shown to hold for both types of reaction at divalent metal ions for a wide variety of solvents and ligands, after corrections have been made for ligand-field stabilisation. Water occupies a middle position in the range of solvents. The results are interpreted in terms of a structural model for a solvated ion in solution, based on that of Frank and Wen.","PeriodicalId":17321,"journal":{"name":"Journal of The Chemical Society A: Inorganic, Physical, Theoretical","volume":"36 1","pages":"2198-2207"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86980279","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}
The reactions of acetylene and propyne at the surface of liquid sodium have been studied at 110, 150, and 200 °C. A fresh metal surface was maintained by magnetic stirring, so arranged that the metal poured continuously over a baffle plate. The course of the reactions was followed from pressure–time curves, and the i.r. spectra of the gas phase. At 110 °C, propyne reacts smoothly according to equation (i) and all hydrogen atoms produced at the 3MeCCH + 2Na → 2NaCCMe + MeCHCH2(i), surface of the metal are employed in the hydrogenation of propyne to propene. A smaller effect (probably polymerisation) also becomes evident at 200 °C. The behaviour of acetylene is markedly different, and the reaction proceeds in two stages. In the first, disodium acetylide (but no hydrogen acetylide) is formed, and the gas phase consists of hydrogen and ethylene in the ratio 1·42 : 1 at 150 °C. No ethane was detected. The second stage involves reaction of hydrogen with sodium metal, and this does not commence until all acetylene is removed from the gas phase. The results are discussed qualitatively in terms of the relative absorption of the gases at the sodium surface, which may have some analogies with their absorption coefficients at transition-metal surfaces.
{"title":"The reactions of acetylene and propyne at the surface of liquid sodium","authors":"C. C. Addison, M. Hobdell, R. J. Pulham","doi":"10.1039/J19710001704","DOIUrl":"https://doi.org/10.1039/J19710001704","url":null,"abstract":"The reactions of acetylene and propyne at the surface of liquid sodium have been studied at 110, 150, and 200 °C. A fresh metal surface was maintained by magnetic stirring, so arranged that the metal poured continuously over a baffle plate. The course of the reactions was followed from pressure–time curves, and the i.r. spectra of the gas phase. At 110 °C, propyne reacts smoothly according to equation (i) and all hydrogen atoms produced at the 3MeCCH + 2Na → 2NaCCMe + MeCHCH2(i), surface of the metal are employed in the hydrogenation of propyne to propene. A smaller effect (probably polymerisation) also becomes evident at 200 °C. The behaviour of acetylene is markedly different, and the reaction proceeds in two stages. In the first, disodium acetylide (but no hydrogen acetylide) is formed, and the gas phase consists of hydrogen and ethylene in the ratio 1·42 : 1 at 150 °C. No ethane was detected. The second stage involves reaction of hydrogen with sodium metal, and this does not commence until all acetylene is removed from the gas phase. The results are discussed qualitatively in terms of the relative absorption of the gases at the sodium surface, which may have some analogies with their absorption coefficients at transition-metal surfaces.","PeriodicalId":17321,"journal":{"name":"Journal of The Chemical Society A: Inorganic, Physical, Theoretical","volume":"41 1","pages":"1704-1708"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86982343","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}
Three-dimensional X-ray crystal structure analyses have been carried out on the compounds MIH[C5H4BrN2O3]2. For MI= K, Z= 4 in a monoclinic unit cell having a= 14·884, b 14·779, c= 7·135 A, β= 97·61°, and space group l2/c. The cation lies on a two-fold axis which relates two anionic moieties with a short [2·42(2)A] hydrogen bond between oxygen atoms. The potassium is ten-co-ordinate and K–O distances range from 2·739–3·105(9)A, mean 2·944 A; each uracil chelates two potassium ions and makes one contact with a third. These K–O contacts and the ‘symmetrical’ hydrogen bond hold the structure in columns along the needle axis of the crystal, c. Hydrogen bonds N–H ⋯ O, 2·73(1)A, hold the columns together in the other two directions.For M1= Rb, Z= 4 in an orthorhombic unit cell having a= 5·995, b= 21·825, c= 11·932 A and space group lba2. The rubidium ion is on a two-fold axis and is six-co-ordinated by a trigonal prism of oxygen atoms at distances from 2·93–3·00(1)A, mean 2·977 A. The three oxygen atoms of one uracil moiety make contact with different rubidium ions and each oxygen with only one rubidium. Metal–oxygen contacts and hydrogen bonds [N–H ⋯ O 2·88(3) and O ⋯ O 2·42(5)A] hold the structure in layers; shortest contacts between the layers are Br ⋯ Me 3·59 and Br ⋯ Br 3·68 A. The shorter hydrogen bond joins N(3) oxygen atoms across a two-fold axis.The differences in structure are correlated with differences in the i.r. spectra.
{"title":"Crystal structures of the non-isomorphous potassium and rubidium acid salts of 5-bromo-3-hydroxy-6-methyluracil","authors":"M. Truter, B. Vickery","doi":"10.1039/J19710002077","DOIUrl":"https://doi.org/10.1039/J19710002077","url":null,"abstract":"Three-dimensional X-ray crystal structure analyses have been carried out on the compounds MIH[C5H4BrN2O3]2. For MI= K, Z= 4 in a monoclinic unit cell having a= 14·884, b 14·779, c= 7·135 A, β= 97·61°, and space group l2/c. The cation lies on a two-fold axis which relates two anionic moieties with a short [2·42(2)A] hydrogen bond between oxygen atoms. The potassium is ten-co-ordinate and K–O distances range from 2·739–3·105(9)A, mean 2·944 A; each uracil chelates two potassium ions and makes one contact with a third. These K–O contacts and the ‘symmetrical’ hydrogen bond hold the structure in columns along the needle axis of the crystal, c. Hydrogen bonds N–H ⋯ O, 2·73(1)A, hold the columns together in the other two directions.For M1= Rb, Z= 4 in an orthorhombic unit cell having a= 5·995, b= 21·825, c= 11·932 A and space group lba2. The rubidium ion is on a two-fold axis and is six-co-ordinated by a trigonal prism of oxygen atoms at distances from 2·93–3·00(1)A, mean 2·977 A. The three oxygen atoms of one uracil moiety make contact with different rubidium ions and each oxygen with only one rubidium. Metal–oxygen contacts and hydrogen bonds [N–H ⋯ O 2·88(3) and O ⋯ O 2·42(5)A] hold the structure in layers; shortest contacts between the layers are Br ⋯ Me 3·59 and Br ⋯ Br 3·68 A. The shorter hydrogen bond joins N(3) oxygen atoms across a two-fold axis.The differences in structure are correlated with differences in the i.r. spectra.","PeriodicalId":17321,"journal":{"name":"Journal of The Chemical Society A: Inorganic, Physical, Theoretical","volume":"41 1","pages":"2077-2083"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85345618","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}
The compounds WF6–n(OR)n(R = Me, n= 1–5; R = Ph, n= 1,2), WOF4L [L = Me2O or (MeO)2P(O)Me] and (MeO)3PMe+WOF5– have been studied by use of 19F–{183W}, 19F–{19F}, 1H–{19F}, and 1H–{31P} double-resonance techniques. 183W Chemical shifts are reported and the factors affecting these and the 19F shifts are discussed. By similar techniques WOF4,OS(OMe)2 and the µ-fluoro-bis[oxotetrafluorotungstate(VI)] anion, W2O2F9–, have been identified as products from the reaction of WF5OMe with (MeO)2SO. The coupling constants 2J(FcFt), 1J(FcW), and 1J(FtW)(Fc,Ft, cis and trans respectively to oxygen) all have the same sign in WF5OR and cis-WF4(OMe)2 but 1J(FcW) is of opposite sign to J(FcW) and J(FcFt) in WOF5– and W2O2F9–.
{"title":"Magnetic double-resonance study of some derivatives of tungsten hexafluoride and tungsten oxotetrafluoride","authors":"W. Mcfarlane, A. M. Noble, J. M. Winfield","doi":"10.1039/J19710000948","DOIUrl":"https://doi.org/10.1039/J19710000948","url":null,"abstract":"The compounds WF6–n(OR)n(R = Me, n= 1–5; R = Ph, n= 1,2), WOF4L [L = Me2O or (MeO)2P(O)Me] and (MeO)3PMe+WOF5– have been studied by use of 19F–{183W}, 19F–{19F}, 1H–{19F}, and 1H–{31P} double-resonance techniques. 183W Chemical shifts are reported and the factors affecting these and the 19F shifts are discussed. By similar techniques WOF4,OS(OMe)2 and the µ-fluoro-bis[oxotetrafluorotungstate(VI)] anion, W2O2F9–, have been identified as products from the reaction of WF5OMe with (MeO)2SO. The coupling constants 2J(FcFt), 1J(FcW), and 1J(FtW)(Fc,Ft, cis and trans respectively to oxygen) all have the same sign in WF5OR and cis-WF4(OMe)2 but 1J(FcW) is of opposite sign to J(FcW) and J(FcFt) in WOF5– and W2O2F9–.","PeriodicalId":17321,"journal":{"name":"Journal of The Chemical Society A: Inorganic, Physical, Theoretical","volume":"66 6 1","pages":"948-953"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90710981","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}
The preparation and characterization of trans-[Co(NH3)4NO2Cl]+ and trans-[Co(NH3)4NO2Br]+ cations are described. The assignment of geometric configuration is based on 1H n.m.r. spectroscopy. The kinetics of the aquation and base hydrolysis of these two complex cations have been studied over a range of temperature. The first-order aquation rate constants are greater than those of the corresponding bis(ethylenediamine) and 1,4,8,11-tetra-azacyclotetradecane complexes, whereas the second-order base hydrolysis rate constants are less. These results are consistent with the kinetic nephelauxetic effect of these amine ligands on the central cobalt(III) ion. Unimolecular reaction mechanisms are assigned to these reactions.
{"title":"Structural and mechanistic studies of co-ordination compounds. Part II. Preparation, aquation, and base hydrolysis of trans-chloronitro- and trans-bromonitro-tetra-amminecobalt(III) cations","authors":"C. Poon, H. Tong","doi":"10.1039/J19710002151","DOIUrl":"https://doi.org/10.1039/J19710002151","url":null,"abstract":"The preparation and characterization of trans-[Co(NH3)4NO2Cl]+ and trans-[Co(NH3)4NO2Br]+ cations are described. The assignment of geometric configuration is based on 1H n.m.r. spectroscopy. The kinetics of the aquation and base hydrolysis of these two complex cations have been studied over a range of temperature. The first-order aquation rate constants are greater than those of the corresponding bis(ethylenediamine) and 1,4,8,11-tetra-azacyclotetradecane complexes, whereas the second-order base hydrolysis rate constants are less. These results are consistent with the kinetic nephelauxetic effect of these amine ligands on the central cobalt(III) ion. Unimolecular reaction mechanisms are assigned to these reactions.","PeriodicalId":17321,"journal":{"name":"Journal of The Chemical Society A: Inorganic, Physical, Theoretical","volume":"37 1","pages":"2151-2154"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91027825","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}
Using simple models for calculation it is shown that light atom M–O–M systems can possess ‘pseudo-linear’ vibrational characteristics until the interbond angle closes beyond the region of 140°.
用简单的模型计算表明，轻原子M-O-M体系在键间角关闭超过140°区域之前具有“伪线性”振动特性。
{"title":"The vibrational spectra of systems containing linear or non-linear M–O–M linkages","authors":"I. R. Beattie, M. Gall","doi":"10.1039/J19710003569","DOIUrl":"https://doi.org/10.1039/J19710003569","url":null,"abstract":"Using simple models for calculation it is shown that light atom M–O–M systems can possess ‘pseudo-linear’ vibrational characteristics until the interbond angle closes beyond the region of 140°.","PeriodicalId":17321,"journal":{"name":"Journal of The Chemical Society A: Inorganic, Physical, Theoretical","volume":"119 1","pages":"3569-3571"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89450742","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}
A direct method of trimethylsilylation reported previously for hemimorphite was applied to other silicates with well-defined structures. For anhydrous minerals the presence of water in the reaction medium was essential for trimethylsilylation. The effects of water and of time, temperature, and concentration of reagents on the trimethylsilylation were studied. A unified procedure was developed for conversion of orthosilicates to trimethylsilyl derivatives of the anion SiO44–, pyrosilicates to trimethylsilyl derivatives of Si2O76–, and silicates with a tetrameric ring structure to trimethylsilyl derivatives of Si4O128–, and for determination of these structures by gas–liquid partition chromatography.
{"title":"Trimethylsilyl derivatives for the study of silicate structures. Part II. Orthosilicate, pyrosilicate, and ring structures","authors":"J. Götz, C. R. Masson","doi":"10.1039/J19710000686","DOIUrl":"https://doi.org/10.1039/J19710000686","url":null,"abstract":"A direct method of trimethylsilylation reported previously for hemimorphite was applied to other silicates with well-defined structures. For anhydrous minerals the presence of water in the reaction medium was essential for trimethylsilylation. The effects of water and of time, temperature, and concentration of reagents on the trimethylsilylation were studied. A unified procedure was developed for conversion of orthosilicates to trimethylsilyl derivatives of the anion SiO44–, pyrosilicates to trimethylsilyl derivatives of Si2O76–, and silicates with a tetrameric ring structure to trimethylsilyl derivatives of Si4O128–, and for determination of these structures by gas–liquid partition chromatography.","PeriodicalId":17321,"journal":{"name":"Journal of The Chemical Society A: Inorganic, Physical, Theoretical","volume":"33 1","pages":"686-688"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89916514","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}
The complexes halogenocyclopentadienyldiquinolin-8-olatometal(IV), C5H5MXox2(M = Ti, Zr; X = Cl, Br and M = Hf, X = Cl), have been prepared by the direct interaction of quinolin-8-ol (oxH) and dihalogenobis(cyclopentadienyl)metal(IV)[(C5H5)2MX2] in acetonitrile solution at room temperature. Reactions of these complexes with ethanol, with ethoxide, and with hydrogen halides have been studied. I.r. (4000–80 cm.–1), n.m.r., and mass spectra are reported.
配合物卤代环戊二烯二喹啉-8-羟基金属(IV)， C5H5MXox2(M = Ti, Zr;用喹啉-8-醇(oxH)和二卤代烃(环戊二烯基)金属(IV)[(C5H5)2MX2]在室温下在乙腈溶液中直接相互作用制备了X = Cl, Br和M = Hf, X = Cl)。研究了这些配合物与乙醇、乙醇和卤化氢的反应。报告了I.r (4000-80 cm - 1)、n.m.r和质谱。
{"title":"Reactions of quinolin-8-ol with covalent halides. Part VI. Bis-π-cyclopentadienyldihalides of titanium, zirconium, and hafnium","authors":"J. Charalambous, M. Frazer, W. Newton","doi":"10.1039/J19710002487","DOIUrl":"https://doi.org/10.1039/J19710002487","url":null,"abstract":"The complexes halogenocyclopentadienyldiquinolin-8-olatometal(IV), C5H5MXox2(M = Ti, Zr; X = Cl, Br and M = Hf, X = Cl), have been prepared by the direct interaction of quinolin-8-ol (oxH) and dihalogenobis(cyclopentadienyl)metal(IV)[(C5H5)2MX2] in acetonitrile solution at room temperature. Reactions of these complexes with ethanol, with ethoxide, and with hydrogen halides have been studied. I.r. (4000–80 cm.–1), n.m.r., and mass spectra are reported.","PeriodicalId":17321,"journal":{"name":"Journal of The Chemical Society A: Inorganic, Physical, Theoretical","volume":"81 1","pages":"2487-2491"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89731980","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}
The photochemistry of tocoquinone-1 has been investigated by use of steady-state and flash photolysis techniques. In polar solvents proton transfer leads to a long-lived transient assigned to an ortho-quinone methide. The photochemical behaviour of tocoquinone-1 is compared with that of vitamin K1.
{"title":"Photochemistry of tocoquinone-1","authors":"G. Leary","doi":"10.1039/J19710002248","DOIUrl":"https://doi.org/10.1039/J19710002248","url":null,"abstract":"The photochemistry of tocoquinone-1 has been investigated by use of steady-state and flash photolysis techniques. In polar solvents proton transfer leads to a long-lived transient assigned to an ortho-quinone methide. The photochemical behaviour of tocoquinone-1 is compared with that of vitamin K1.","PeriodicalId":17321,"journal":{"name":"Journal of The Chemical Society A: Inorganic, Physical, Theoretical","volume":"1 1","pages":"2248-2250"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89742624","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 the five-co-ordinate [Ni(NP3)X]X complexes [NP3= tris(2-diphenylphosphinoethyl)amine; X = Cl, Br, I] with MX2 salts (M = Fe, Co, Ni, Zn) gives complexes of general formula NiM(NP3)X4. Spectrophotometric, conductometric, and far-i.r. data suggest for these complexes a binuclear non-ionic structure consisting of a square-planar ‘core’ with a NiNP2X chromophore, and a pseudo-tetrahedral ‘core’ with a MPX3 chromophore. The analogous nickel–manganese complexes undergo selective oxidation with formation of a phosphine oxide, probably bonded to MnII.
{"title":"Binuclear mixed-metal complexes formed by nickel(II) and other 3d bivalent ions with tripod ligands","authors":"M. Bacci, R. Morassi, L. Sacconi","doi":"10.1039/J19710003686","DOIUrl":"https://doi.org/10.1039/J19710003686","url":null,"abstract":"Reaction of the five-co-ordinate [Ni(NP3)X]X complexes [NP3= tris(2-diphenylphosphinoethyl)amine; X = Cl, Br, I] with MX2 salts (M = Fe, Co, Ni, Zn) gives complexes of general formula NiM(NP3)X4. Spectrophotometric, conductometric, and far-i.r. data suggest for these complexes a binuclear non-ionic structure consisting of a square-planar ‘core’ with a NiNP2X chromophore, and a pseudo-tetrahedral ‘core’ with a MPX3 chromophore. The analogous nickel–manganese complexes undergo selective oxidation with formation of a phosphine oxide, probably bonded to MnII.","PeriodicalId":17321,"journal":{"name":"Journal of The Chemical Society A: Inorganic, Physical, Theoretical","volume":"2 1","pages":"3686-3689"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90109634","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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