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1、常用溶剂性质及相关知识7512J.Org.Chem.1997,62,7512-7515NMRChemicalShiftsofCommonLaboratorySolventsasTraceImpuritiesHugoE.Gottlieb,*VadimKotlyar,andAbrahamNudelman*DepartmentofChemistry,Bar-IlanUniversity,Ramat-Gan52900,IsraelReceivedJune27,1997Inthecourseoftherout
2、ineuseofNMRasanaidfororganicchemistry,aday-to-dayproblemistheidentifica-tionofsignalsderivingfromcommoncontaminants(water,solvents,stabilizers,oils)inless-than-analyti-cally-puresamples.Thisdatamaybeavailableintheliterature,butthetimeinvolvedinsearchin
3、gforitmaybeconsiderable.Anotherissueistheconcentrationdependenceofchemicalshifts(especially1H);resultsobtainedtwoorthreedecadesagousuallyrefertomuchFigure1.ChemicalshiftofHDOasafunctionoftempera-moreconcentratedsamples,andrunatlowermagneticture.fields,
4、thantoday'spractice.Wethereforedecidedtocollect1Hand13Cchemicaldependent(videinfra).Also,anypotentialhydrogen-shiftsofwhatare,inourexperience,themostpopularbondacceptorwilltendtoshiftthewatersignaldown-ªextrapeaksºinavarietyofcommonlyusedNMRfield;thisi
5、sparticularlytruefornonpolarsolvents.Insolvents,inthehopethatthiswillbeofassistancetocontrast,ine.g.DMSOthewaterisalreadystronglythepracticingchemist.hydrogen-bondedtothesolvent,andsoluteshaveonlyanegligibleeffectonitschemicalshift.ThisisalsotrueExperi
6、mentalSectionforD2O;thechemicalshiftoftheresidualHDOisveryNMRspectraweretakeninaBrukerDPX-300instrumenttemperature-dependent(videinfra)but,maybecounter-(300.1and75.5MHzfor1Hand13C,respectively).Unlessintuitively,remarkablysolute(andpH)independent.other
7、wiseindicated,allwererunatroomtemperature(24(1Wethenadded3íLofoneofourstocksolutionsto°C).Fortheexperimentsinthelastsectionofthispaper,probetheNMRtube.ThechemicalshiftswerereadandaretemperaturesweremeasuredwithacalibratedEurotherm840/TpresentedinTable1
8、.Exceptwhereindicated,thedigitalthermometer,connectedtoathermocouplewhichwascouplingconstants,andthereforethepeakshapes,areintroducedintoanNMRtubefilledwithmineraloiltoap-proximatelythesamelevelasatypicalsample.Ateachessentiallysolvent-
