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| 5 - halo uracil proton transfer isomerization and Raman spectroscopy density functional theory
sontautomersof5-fluorouraciland5-chlorouracil [J]. AChimicaSinica, 2005,16 (63) :1495-1499DensityFunctionalTheoryandRamanSpectroscopyStudyoftheProtonTransferTautomerismof5-HalogenouracilsWANGYa-qiong, ZHANGShu-qiang, ZHENGXu-ming (CollegeofScience, ZhejiangSci-TechUniversity, Hangzhou310018, China) Abstract: Sevenprotontransfertautomerizationchannelsof5-halogenouracil (5 a XU,mbt shoes sale, X: F,ralph lauren outlet, Cl , Br, I) wereinvestigatedusingdensityfunctionaltheorycomputationsattheB3LYP/6-31G (d) leveloftheory. Thegeometrystructuresandtherelativeenergiesforalltautomersaswellasthecorrespondingtransition-statesarereported. Theresultsindicatethattheelectron-withdrawingcapacityofsubstituent (X) for5-halogenouracilhavelittleeffectonthestabilityofprotontransfertautomers,mbt shoes on sale, thoughtheenergybarrierforeachprotontransfertautomerizationsdiffers. Therearethreeprotontransferstepsfor5-halogenouracilsthatdisplaythreedifferentenergybarrier: 188 ~ 214kJ · mol a forthefirststep, 158 ~ 171kJ · mol a forthesecondstep, and145 ~ 155kJ · mol a forthirdstep. TheFT. . Ramanspectraof5-iodouracilanduracilaremeasuredandtheirsimilaritiesandthedifferenceswerediscussedinRamanfrequencyandRamanintensity. TheRamanactivityofC4 a C5/C5 a C6stretchingmode,tory burch outlet, C4 a Olostretc-hingmodeandN3 a H9waggingmodefor5-iodouracildifferssignificantlyfromuracil. Itshowsthatlightorelectro-magneticfieldhasgreateffectontheelectronclouddistributionofC4 a OlobondandN3 a H9bondandmightselec-tivelyfavortheXU1-'XU3protontransferprocess. Keywords: Protontransfer; 5-Halogenouracils; Densityfunctionaltheory; VI 'A raman (Editor: Xu Hui children) More articles related to topics： tory burch outlet Agent Intrusion Detection System mac cosmetics wholesale AT24C512 memory devices in mac cosmetics wholesale A201C, D Comber Nipper mot |
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