The crystal structure of the title compound, the ‘pentamer’ fraction of the acid-catalysed polymerisation of thiophen, has been determined by direct methods from three-dimensional photographic data. The crystals are monoclinic, space group, P21/c(C52h), with a= 14·13, b= 7·68, c= 13·78 A and β= 104·1°. The disordered structure has been refined by least-squares methods to R 0·111 over 2307 independent reflexions. The cyclohexene ring adopts the half-chair conformation with the thienyl substituents in a cis-configuration.
{"title":"Crystal and molecular structure of 4,7-di-(2-thienyl)-4,5,6,7-tetrahydrobenzo[b]thiophen","authors":"D. M. Hawley, G. Ferguson","doi":"10.1039/J29710000843","DOIUrl":"https://doi.org/10.1039/J29710000843","url":null,"abstract":"The crystal structure of the title compound, the ‘pentamer’ fraction of the acid-catalysed polymerisation of thiophen, has been determined by direct methods from three-dimensional photographic data. The crystals are monoclinic, space group, P21/c(C52h), with a= 14·13, b= 7·68, c= 13·78 A and β= 104·1°. The disordered structure has been refined by least-squares methods to R 0·111 over 2307 independent reflexions. The cyclohexene ring adopts the half-chair conformation with the thienyl substituents in a cis-configuration.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"34 1","pages":"843-846"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74989588","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 crystal structure of 8,12-diethyl-2,3,7,13,17,18-hexamethylcorrole has been elucidated by X-ray crystallographic analysis and the geometry of the macrocyclic ring system has been found to be not strictly planar. The distortions are probably caused by short N–N contacts brought on by the direct C(1)–C(19) link. The ‘ruffling’ of the pyrrole rings is similar to that found in some substituted porphyrins, although individual ring geometries have been altered by the inner crowding. Crystallographic evidence suggests that the three inner hydrogen atoms are statistically distributed among the four nitrogen atoms. Packing is in the ‘parallel disc’ mode and is specific for the molecular distortion.
{"title":"Crystal and molecular structure of 8,12-diethyl-2,3,7,13,17,18-hexamethylcorrole","authors":"H. R. Harrison, O. Hodder, D. Hodgkin","doi":"10.1039/J29710000640","DOIUrl":"https://doi.org/10.1039/J29710000640","url":null,"abstract":"The crystal structure of 8,12-diethyl-2,3,7,13,17,18-hexamethylcorrole has been elucidated by X-ray crystallographic analysis and the geometry of the macrocyclic ring system has been found to be not strictly planar. The distortions are probably caused by short N–N contacts brought on by the direct C(1)–C(19) link. The ‘ruffling’ of the pyrrole rings is similar to that found in some substituted porphyrins, although individual ring geometries have been altered by the inner crowding. Crystallographic evidence suggests that the three inner hydrogen atoms are statistically distributed among the four nitrogen atoms. Packing is in the ‘parallel disc’ mode and is specific for the molecular distortion.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"127 1","pages":"640-645"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77515604","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 5-nitro-, 5-chloro-, 5-methyl-, and unsubstituted-1,3-dimethylbenzimidazolium ions react with mercury(II) chloride in mildly alkaline solution to give the corresponding 2-[chloromercury(II)]-derivatives. The latter are stable for long periods in aqueous perchloric acid at 65°, but readily undergo acidolysis in the presence of chloride ion, through unimolecular heterolysis of the corresponding dichloro- and trichloro-mercury(II) derivatives. The effect of substituents on the rate of the one-chloride-ion catalysis is small, and on the rate of the two-chloride-ion-catalysed acidolysis is even smaller.
{"title":"N-substituted heterocyclic cations. Part IX. The preparation and chloride-ion catalysed unimolecular acidolysis of 2-[chloromercury(II)]-1,3-dimethylbenzimidazolium ions in aqueous solution","authors":"C. Cooksey, D. Dodd, M. D. Johnson","doi":"10.1039/J29710001380","DOIUrl":"https://doi.org/10.1039/J29710001380","url":null,"abstract":"The 5-nitro-, 5-chloro-, 5-methyl-, and unsubstituted-1,3-dimethylbenzimidazolium ions react with mercury(II) chloride in mildly alkaline solution to give the corresponding 2-[chloromercury(II)]-derivatives. The latter are stable for long periods in aqueous perchloric acid at 65°, but readily undergo acidolysis in the presence of chloride ion, through unimolecular heterolysis of the corresponding dichloro- and trichloro-mercury(II) derivatives. The effect of substituents on the rate of the one-chloride-ion catalysis is small, and on the rate of the two-chloride-ion-catalysed acidolysis is even smaller.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"34 1 1","pages":"1380-1384"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77675164","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 syn-(alkylthio)-configuration of the thermodynamically more stable α-isomer of S-cyanoethyl acetothio-hydroximate has been confirmed by crystal-structure determination. The compound crystallizes in the monoclinic space group P21/c, with a= 16·535 ± 0·011, b= 4·654 ± 0·003, c= 19·536 ± 0·012 A, β= 106° 44′± 2′, and Z= 8. The X-ray intensities were measured on a computer-controlled four-circle diffractometer with Mo-Kα radiation. The atomic co-ordinates were determined by Fourier and least-squares methods to give R 0·069 over 903 independent reflections. The CN, CN, N–O, C(sp)–C(sp3), C(sp2)–C(sp3), C(sp3)–C(sp3), S–C(sp2), and S–C(sp3) bonds have lengths of 1·28, 1·13, 1·41, 1·45, 1·50, 1·52, 1·76, and 1·82 A, respectively, with standard deviations of ca. 0·01 A.
{"title":"Configuration of the S-alkyl thiohydroximates: crystal-structure analysis of the syn-(alkylthio)-isomer of S-cyanoethyl acetothiohydroximate","authors":"M. Waite, G. Sim","doi":"10.1039/J29710001102","DOIUrl":"https://doi.org/10.1039/J29710001102","url":null,"abstract":"The syn-(alkylthio)-configuration of the thermodynamically more stable α-isomer of S-cyanoethyl acetothio-hydroximate has been confirmed by crystal-structure determination. The compound crystallizes in the monoclinic space group P21/c, with a= 16·535 ± 0·011, b= 4·654 ± 0·003, c= 19·536 ± 0·012 A, β= 106° 44′± 2′, and Z= 8. The X-ray intensities were measured on a computer-controlled four-circle diffractometer with Mo-Kα radiation. The atomic co-ordinates were determined by Fourier and least-squares methods to give R 0·069 over 903 independent reflections. The CN, CN, N–O, C(sp)–C(sp3), C(sp2)–C(sp3), C(sp3)–C(sp3), S–C(sp2), and S–C(sp3) bonds have lengths of 1·28, 1·13, 1·41, 1·45, 1·50, 1·52, 1·76, and 1·82 A, respectively, with standard deviations of ca. 0·01 A.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"36 1","pages":"1102-1105"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78050719","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}
When a solution of potassium ferrioxalate containing 0·02% of o-phenanthroline monohydrate and acetate buffer (final pH 3·7) is irradiated with 2537 and 3650 A light, the absorbance at 5100 A due to the formation of the ferrous o-phenanthroline complex has been found to increase linearly with dose. The suitability of this system as a more convenient chemical actinometer is discussed here.
{"title":"A modification to the ferrioxalate actinometer","authors":"K. C. Kurien","doi":"10.1039/J29710002081","DOIUrl":"https://doi.org/10.1039/J29710002081","url":null,"abstract":"When a solution of potassium ferrioxalate containing 0·02% of o-phenanthroline monohydrate and acetate buffer (final pH 3·7) is irradiated with 2537 and 3650 A light, the absorbance at 5100 A due to the formation of the ferrous o-phenanthroline complex has been found to increase linearly with dose. The suitability of this system as a more convenient chemical actinometer is discussed here.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"459 1","pages":"2081-2082"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79814049","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 SN1 methanolysis of 2-phenylthio-1,2-di-p-tolylvinyl 2,4,6-trinitrobenzenesulphonates in 4:1 acetone–methanol at 25 °C is at least 97% stereospecific. ‘Retention’ of configuration is probably involved. The pair of structural isomers 2-phenyl-2-phenylthio-1-p-tolylvinyl and 1-phenyl-2-phenylthio-2-p-tolylvinyl trinitrobenzene-sulphonates was prepared in mixtures of different composition (from 3:1 to 1:2). The methanolysis in 4:1 acetone–methanol at 25 °C of such mixtures gives the two isomers, 1-methoxy-2-phenyl-2-phenylthio-1-p-tolylethylene and 1-methoxy-1-phenyl-2-phenylthio-2-p-tolylethylene in a ratio of ca. 4·5:1. This ratio is independent on the proportion of the two isomers in the starting material. Similarly, in nitromethane at 25 °C, mixtures of the p-tolylthio-analogues give the two isomers, 6-methyl-2-phenyl-3-p-tolylbenzo[b]thiophen and 6-methyl-2-p-tolyl-3-phenylbenzo[b]thiophen in a ratio of 5:1 independently on the isomeric distribution in the reagents.Both retention of configuration and migration of the β-arylthio-group are evidence of β-sulphur participation and indicate that a bridged structure, probably a thiirenium ion, is involved as an intermediate in an SN1 reaction of β-arylthiovinyl sulphonic esters.
{"title":"Reactivity of vinyl sulphonic esters. Part V. Stereochemistry and rearrangements in SN1 reactions of β-thiovinyl trinitrobenzenesulphonates","authors":"G. Modena, U. Tonellato","doi":"10.1039/J29710000381","DOIUrl":"https://doi.org/10.1039/J29710000381","url":null,"abstract":"The SN1 methanolysis of 2-phenylthio-1,2-di-p-tolylvinyl 2,4,6-trinitrobenzenesulphonates in 4:1 acetone–methanol at 25 °C is at least 97% stereospecific. ‘Retention’ of configuration is probably involved. The pair of structural isomers 2-phenyl-2-phenylthio-1-p-tolylvinyl and 1-phenyl-2-phenylthio-2-p-tolylvinyl trinitrobenzene-sulphonates was prepared in mixtures of different composition (from 3:1 to 1:2). The methanolysis in 4:1 acetone–methanol at 25 °C of such mixtures gives the two isomers, 1-methoxy-2-phenyl-2-phenylthio-1-p-tolylethylene and 1-methoxy-1-phenyl-2-phenylthio-2-p-tolylethylene in a ratio of ca. 4·5:1. This ratio is independent on the proportion of the two isomers in the starting material. Similarly, in nitromethane at 25 °C, mixtures of the p-tolylthio-analogues give the two isomers, 6-methyl-2-phenyl-3-p-tolylbenzo[b]thiophen and 6-methyl-2-p-tolyl-3-phenylbenzo[b]thiophen in a ratio of 5:1 independently on the isomeric distribution in the reagents.Both retention of configuration and migration of the β-arylthio-group are evidence of β-sulphur participation and indicate that a bridged structure, probably a thiirenium ion, is involved as an intermediate in an SN1 reaction of β-arylthiovinyl sulphonic esters.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"57 1","pages":"381-385"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80238726","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 hydrolysis rate constant for acylchymotrypsins correlates with the rate constant for reaction of hydroxide ion with the ethyl esters (slope = 0·64, r= 0·867) over a wide range of structure variation in the acyl group. The low sensitivity to change of acyl group and to change in σ for benzoylchymotrypsins (ρ= 1·55, r= 0·952) is suggested to be due to electrophilic participation at the carbonyl oxygen of the acyl group. Tosylchymotrypsin is suggested as a model for the tetrahedral adduct of 4-methylbenzoylchymotrypsin with water and the electrophiles are identified as the NH groups of gly-193, asp-194, and ser-195 peptide bonds.
{"title":"Hydrolysis of acylchymotrypsins","authors":"Andrew Williams, G. Salvadori","doi":"10.1039/J29710002401","DOIUrl":"https://doi.org/10.1039/J29710002401","url":null,"abstract":"The hydrolysis rate constant for acylchymotrypsins correlates with the rate constant for reaction of hydroxide ion with the ethyl esters (slope = 0·64, r= 0·867) over a wide range of structure variation in the acyl group. The low sensitivity to change of acyl group and to change in σ for benzoylchymotrypsins (ρ= 1·55, r= 0·952) is suggested to be due to electrophilic participation at the carbonyl oxygen of the acyl group. Tosylchymotrypsin is suggested as a model for the tetrahedral adduct of 4-methylbenzoylchymotrypsin with water and the electrophiles are identified as the NH groups of gly-193, asp-194, and ser-195 peptide bonds.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"12 1","pages":"2401-2406"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79074202","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}
1 H N.m.r. data obtained from the direct observation of benzo- and dibenzo-thiopyran SS-dioxide anions and of some methyl derivatives (I)–(IV) are consistent with a substantially trigonal configuration of the carbanion carbon and with extensive delocalisation of the negative charge within the rings. Evidence is also presented for the occurrence of 1H n.m.r. time scale chemical exchange at the methylene group of 1-benzothiopyran SS-dioxide derivatives in methanol and in the presence of sodium methoxide.
从苯并和二苯并-硫代吡喃ss - 2阴离子以及一些甲基衍生物(I) - (IV)的直接观察中获得的1 H n .m.r数据与碳离子碳的基本三角构型和环内负电荷的广泛离域一致。在甲醇和甲醇钠存在的情况下，1-苯并噻吩吡喃ss -二氧化衍生物的亚甲基发生了1H nmrr时间尺度的化学交换。
{"title":"Cyclic sulphones. Part XI. Extensive delocalisation in benzo- and dibenzo-thiopyran SS-dioxide anions","authors":"S. Bradamante, A. Mangia, G. Pagani","doi":"10.1039/J29710000545","DOIUrl":"https://doi.org/10.1039/J29710000545","url":null,"abstract":"1 H N.m.r. data obtained from the direct observation of benzo- and dibenzo-thiopyran SS-dioxide anions and of some methyl derivatives (I)–(IV) are consistent with a substantially trigonal configuration of the carbanion carbon and with extensive delocalisation of the negative charge within the rings. Evidence is also presented for the occurrence of 1H n.m.r. time scale chemical exchange at the methylene group of 1-benzothiopyran SS-dioxide derivatives in methanol and in the presence of sodium methoxide.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"1 1","pages":"545-548"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81425065","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 kinetics of oxidation of pinacol by periodate have been studied at 0° and 25° over the range pH 0–13. The kinetics are second order except at 0° and pH >11. Under the latter conditions, with excess pinacol, the kinetics are those of consecutive first-order reactions, showing that an intermediate is being formed in appreciable concentration. Several features of the kinetics resemble closely those observed for the formation of the cyclic ester from propane-1,2-diol and periodate. It is concluded that the oxidations of pinacol and propane-1,2-diol by periodate proceed via a mechanism which is probably common to all oxidations of 1,2-diols by periodate, viz. the formation of a periodate monoester, followed by ring-closure to a cyclic ester, then decomposition of a monoanion of the cyclic ester to the reaction products. The stages of the mechanism are discussed in detail, and it is shown that the different types of pH dependence observed in the oxidation of 1,2-diols by periodate can be readily accommodated by this mechanism. The stability of the periodate esters is discussed, and it is concluded that the general order of stability of esters containing six-co-ordinated iodine is: cyclic triester > cyclic diester (5-membered ring) > cyclic diester (6-membered ring) > monoester. A comparison of the acid strengths of H5IO6 and cyclic periodate esters suggests that the periodiate di- and tri-anions are appreciably dehydrated in aqueous solution to HIO52– and IO53–.
{"title":"The mechanism of oxidation of α-glycols by periodic acid. Part X. The oxidation of pinacol, and a general discussion of the stability of periodate esters and their role in the mechanism of oxidation","authors":"G. Buist, C. A. Bunton, W. S. P. Hipperson","doi":"10.1039/J29710002128","DOIUrl":"https://doi.org/10.1039/J29710002128","url":null,"abstract":"The kinetics of oxidation of pinacol by periodate have been studied at 0° and 25° over the range pH 0–13. The kinetics are second order except at 0° and pH >11. Under the latter conditions, with excess pinacol, the kinetics are those of consecutive first-order reactions, showing that an intermediate is being formed in appreciable concentration. Several features of the kinetics resemble closely those observed for the formation of the cyclic ester from propane-1,2-diol and periodate. It is concluded that the oxidations of pinacol and propane-1,2-diol by periodate proceed via a mechanism which is probably common to all oxidations of 1,2-diols by periodate, viz. the formation of a periodate monoester, followed by ring-closure to a cyclic ester, then decomposition of a monoanion of the cyclic ester to the reaction products. The stages of the mechanism are discussed in detail, and it is shown that the different types of pH dependence observed in the oxidation of 1,2-diols by periodate can be readily accommodated by this mechanism. The stability of the periodate esters is discussed, and it is concluded that the general order of stability of esters containing six-co-ordinated iodine is: cyclic triester > cyclic diester (5-membered ring) > cyclic diester (6-membered ring) > monoester. A comparison of the acid strengths of H5IO6 and cyclic periodate esters suggests that the periodiate di- and tri-anions are appreciably dehydrated in aqueous solution to HIO52– and IO53–.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"24 1","pages":"2128-2142"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81531082","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}
Nucleophilic attack upon cyclopentyl, endo-2-norbornyl, endo-5,6-trimethylene-endo-2-norbornyl, endo-5,6-trimethylene-endo-8-norbornyl, and endo-5,6-trimethylene-endo-9-norbornyl cyclic tosylates has been studied. No rearrangement occurred during the reactions. The relative rates of displacement have been found to be very similar to the reactivity observed for solvolyses. Increased steric interaction by alkyl groups on the leaving group causes the displacement rate to decrease.
{"title":"Substitution reactions in cyclic systems. Displacement reactions of some sterically hindered tosylates","authors":"I. Rothberg, R. Russo","doi":"10.1039/J29710001214","DOIUrl":"https://doi.org/10.1039/J29710001214","url":null,"abstract":"Nucleophilic attack upon cyclopentyl, endo-2-norbornyl, endo-5,6-trimethylene-endo-2-norbornyl, endo-5,6-trimethylene-endo-8-norbornyl, and endo-5,6-trimethylene-endo-9-norbornyl cyclic tosylates has been studied. No rearrangement occurred during the reactions. The relative rates of displacement have been found to be very similar to the reactivity observed for solvolyses. Increased steric interaction by alkyl groups on the leaving group causes the displacement rate to decrease.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"6 1","pages":"1214-1218"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81792160","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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