# How can I report ""^13"C" NMR data?

Sep 11, 2015

In a typical lab report, I would expect someone to report the following data:

• Number of unique carbons in the molecular formula
• Number of distinct ""^13 C peaks seen in the spectrum
• Presence or absence of symmetry (such as in a benzene ring with two identical substituents para or meta to each other)
• Chemical shifts of each unique carbon in $\text{ppm}$
• Proposed carbon types (e.g. ${\text{C sp}}^{3}$ (likely alkyl) bonded to carbonyl ${\text{C sp}}^{2}$); this can be an educated guess
• Your carbon labels (e.g. ${\text{C"_A, "C}}_{B}$, etc.)

This is how I tended to do it when I took O-Chem:

Based on the table, I said that ${\text{C}}_{A}$ was the methyl attached to the carbonyl, ${\text{C}}_{F}$, ${\text{C}}_{E}$, and ${\text{C}}_{D}$ were the aromatic carbons, starting from the top carbon on the ring going counterclockwise as well as their symmetric counterparts on the opposite side of the symmetry axis, ${\text{C}}_{C}$ was the aromatic carbon directly connected to the carbonyl carbon, and ${\text{C}}_{B}$ was the carbonyl carbon.

In published research papers though, you should not have any row borders (except those below a heading), nor outermost column borders, at least by ACS convention. Also, you would need a table caption at the top, explaining briefly what the table is showing.

Sep 13, 2015

For a lab report, you follow the format specified by your instructor.

#### Explanation:

If your instructor has not specified a format, Truong-Son N. has provided you with an excellent template in the preceding answer.

Research journals usually have their own formats for the reporting of $\text{^(13)"C}$ NMR data.

These include rules such as:

• The peak shifts should be rounded off to the nearest 0.1 ppm except when greater precision is needed to distinguish closely spaced peaks.
• Information about numbers of hydrogen atoms may be included, in order of increasing number of attached hydrogens.
• Detailed peak assignments should not be included in the Experimental section (they go in the Discussion section).

The usual format is:

$\text{^(13)"C}$ NMR (frequency, solvent) δ in decreasing order of frequency.

Thus, you might see spectra reported in formats such as:

$\text{^(13)"C}$ NMR (50 MHz, ${\text{CDCl}}_{3}$) δ 145.4, 129.3, 128.5, 29.1, 16.0

$\text{^(13)"C}$ NMR (50 MHz, ${\text{CDCl}}_{3}$, DEPT) δ 145.4, 129.3, 128.5, 29.1, 16.0

$\text{^(13)"C}$ NMR (50 MHz, ${\text{CDCl}}_{3}$, DEPT) δ $\text{C}$ 145.4, $\text{CH}$ 128.5, 128.9, 129.3, ${\text{CH}}_{2}$ 29.1, ${\text{CH}}_{3}$ 16.0