Analysis of C-13 NMR Spectra New for this specification

How it works Carbon-13 makes up 1.1% of all naturally occurring carbon atoms. Carbon-13 has 13 nucleons, an odd number so it has a residual magnetic spin. i.e. it shows up on NMR. Carbon -13 atoms in different environments have different chemical shifts. There are no integrals

Carbon-13 chemical shifts

Some C-13 Chemical Shifts 1o Alkyl RCH3 0-40 ppm 2o Alkyl RCH2R 10-50 ppm 3o Alkyl RCHR2 15-50 ppm Alkyl Halide C-X 0-65 ppm Alcohol or ether C-O 50-90 ppm Alkenes and Aromatics C=C 100-170 ppm Amides CO)N 150-180 ppm Carboxylic Acids RCOOH 160-185 Aldehydes/ Ketones -(CO)- 182-215 ppm

Propan-1-ol

Propan-1-ol

Propan-2-ol

Propan-2-ol

2-bromopropane

Ethyl methanol

The reasons for using C-13 spectra are; Fewer peaks to sort out The reasons for using C-13 spectra are; Fewer peaks to sort out. Better separation of certain peaks, like benzene Never any coupling

Isomer Carbon environments Ring environment 4 3 5 2 6 1 1 1 1 1 1 1