Question

Construct a 13C NMR data table for the structure shown. Identify the chemical shifts, and the type of splitting that you\'d expect were a \"coupled\" carbon-NMR to be acquired.

Construct a 13C NMR data table for the structure shown. Identify the chemical shifts, and the type of splitting that you'd expect were a "coupled" carbon-NMR to be acquired. CH3)2CHCH, CH = CHCH,OCH3 0-50 50-100 100-160 160-220 singlet doublet triplet quartet Chem. Shift Splitting

Answer 1

In 13C NMR, the number of signals tells us how many different carbons or set of equivalent carbon atoms are pr esent in the co mpound. The splitting of a signal depends on the hydrogen atoms attached to each carbon (N+1 rule) -CH,-quartet CH2 triplet -CH-doublet -C-singlet The chemical shift predicts the hybridization of each carbon The chemical shift values in 13C NMR for the provided compound are as follows: 23.3 CH3 a bcd HaCCH_CH-CCHCH2-O-CH 57.8 28.8 36.6 29.2 68.0 128.7

Here, carbon a is attached to three carbon atoms, so it splits into quartet and the chemical shift range is in between 0-50 Carbon b is attached to one carbon atom, so it splits into doublet and the chemical shift range is in between 0-50 Carbon c is attached to two carbon atoms, so it splits into triplet and the chemical shift range is in between 0-50 Carbon d is attached to one carbon atoms, so it splits into doublet and the chemical shift range is in between 100-160 Carbon e is attached to one carbon atoms, so it splits into doublet and the chemical shift range is in between 100-160 Carbon f is attached to two carbon atoms, so it splits into triplet and the chemical shift range is in between 50-100 Carbon g is attached to three carbon atoms, so it splits into quartet and the chemical shift range is in between 50-100 Thus, the table is filled with data as follows Chem. Shift Splitting quartet doublet triplet doublet doublet triplet quartet 0-50 0-50 0-50 100-160 100-160 50-100 50-100 9