Transcription of Introduction to 13C-NMR Spectroscopy - Department of …
1 344 Organic Chemistry LaboratoryIntroduction to 13C-NMR SpectroscopyMain topics-13C-atom chemical shift range-1H-coupled and decoupled 13C-NMR Spectrum of n-pentane2three 1H-atom Spectrum of n-hexane3three 1H-atom Spectrum of n-docosane413C is NMR active (I= ); 12C is NMR inactive (I= 0).The natural abundance of 13C is ~ greater chemical shift range provides greater better differentiation of signals; reduced 2ndorder effectsOften the NMR experiment is performed in a 1H-decoupled manner to simplify the spectrum; removes coupling to Spectroscopy5(~220 ppm) Spectrum of n-Hexane6three 13C-atom environmentsCH3OH1H is > 99% abundant; it couples strongly to 13C atom it is attached to (1 JHC= 100-210 Hz) with normal n+1 rulesplitting.
2 512 scans30 min10 M concentrationCDCl3CH3OH13C-NMR Spectrum of Methanol1H Decoupled1H Coupled7 CDCl3 CDCl3CH3CH2 OHCH3CH2 OHCH3CH2 OHCH3CH2OH13C-NMR Spectrum of Ethanol512 scans30 min10 M concentration1H Decoupled1H Coupled813C-NMR Spectroscopy Chemical Shift Ranges9sp2hybridized 13C-atomssp3hybridized 13C-atomssphybridized 13C-atomsReich, Hans J. scans30 M concentrationCDCl3abcdabcdee13C-NMR Spectrum of Ethyl Cyanoacetate101113C-NMR Spectrum of Ethyl NMR Shifts relative to TMS calculated with WebMO/Gaussian09 at B3 LYP/6-31G(d) of 4 -sulfamoylacetanilide Regiochemistry13 Determination of 4 -sulfamoylacetanilide RegiochemistryABCDEF