Chapter 14: Q50P (page 527)
Identify the carbon atoms that give rise to the signals in the \)^{{\bf{13}}}{\bf{C}}\) NMR spectrum of each compound.
a. \){\bf{C}}{{\bf{H}}_{\bf{3}}}{\bf{C}}{{\bf{H}}_{\bf{2}}}{\bf{C}}{{\bf{H}}_{\bf{2}}}{\bf{C}}{{\bf{H}}_{\bf{2}}}{\bf{OH}}\); \)^{{\bf{13}}}{\bf{C}}\) NMR: 14, 19, 35, and 62 ppm
b. \){\left( {{\bf{C}}{{\bf{H}}_{\bf{3}}}} \right)_{\bf{2}}}{\bf{CHCHO}}\); \)^{{\bf{13}}}{\bf{C}}\) NMR: 16, 41, and 205 ppm
c. \){\bf{C}}{{\bf{H}}_{\bf{2}}}{\bf{ = CHCH}}\left( {{\bf{OH}}} \right){\bf{C}}{{\bf{H}}_{\bf{3}}}\); \)^{{\bf{13}}}{\bf{C}}\) NMR: 23, 69, 113, and 143 ppm
Short Answer
Expert verified
a.
b.
c.
Step by step solution
01
Chemical shift (in ppm)
\)^{{\rm{13}}}{\rm{C}}\)spectroscopy is measured in high value of ppm values to represent the chemical shift value.
- The downfield or high value of chemical shift is due to the presence of electron withdrawing species.
- The upfield or low value of chemical shift is due to the presence of electron donor species.
02
Explanation
a.
C is adjacent to the OH which is an electronegative atom. Therefore, C has higher value of chemical shift. Therefore, the chemical shift value is shown as:
b.
C is adjacent to the CHO which is an electronegative atom. Therefore, C has higher value of chemical shift. Therefore, the chemical shift value is shown as:
c.
C of the double bond has higher value of chemical shift due to the presence of an adjacent OH group (electronegative atom). Therefore, the chemical shift value is shown as:
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