¹H NMR and ¹³C NMR are two common types of NMR spectroscopy, and they both provide information about the structure of organic molecules. The main difference is the type of nucleus being observed—hydrogen or carbon.
Here’s a clear comparison:
1. Nucleus Observed
- ¹H NMR: Observes hydrogen atoms (protons) in a molecule.
- ¹³C NMR: Observes carbon-13 nuclei in a molecule.
2. Sensitivity
- ¹H NMR: Very sensitive because hydrogen is abundant (most molecules contain many hydrogens).
- ¹³C NMR: Less sensitive because carbon-13 is only about 1% of all carbon atoms naturally.
3. Signal Count
- ¹H NMR: Shows all non-equivalent hydrogens, and peaks can be split into multiplets due to spin-spin coupling.
- ¹³C NMR: Shows all non-equivalent carbons, but splitting is usually removed using a technique called proton decoupling, so most peaks appear as singlets.
4. Chemical Shift Range
- ¹H NMR: Typically ranges from 0–12 ppm.
- ¹³C NMR: Typically ranges from 0–220 ppm.
5. Information Provided
- ¹H NMR: Gives details about:
- Number of hydrogen atoms in each environment (integration)
- Neighboring hydrogens (splitting patterns)
- Type of hydrogen (alkyl, aromatic, aldehyde, etc.)
- ¹³C NMR: Gives details about:
- Number of unique carbons (peak count)
- Type of carbon (methyl, methylene, quaternary, carbonyl, aromatic, etc.)
- Less detailed about neighboring hydrogens unless special techniques are used
6. Applications
- ¹H NMR: Useful for studying hydrogen placement, functional groups, and connectivity in molecules.
- ¹³C NMR: Useful for determining the carbon skeleton and confirming the structure of the molecule.
In Short
¹H NMR focuses on hydrogens, is very sensitive, and shows splitting patterns.
¹³C NMR focuses on carbons, is less sensitive, usually shows singlets, and helps identify the carbon framework of molecules.