DEPT 135
Definition
A 13C editing experiment that flips CH3 and CH peaks up, CH2 peaks down, and makes quaternary carbons disappear. Used to assign every carbon signal to a multiplicity class without running a full 2D experiment.
- Full name
- Distortionless Enhancement by Polarization Transfer, 135°
- CH3, CH
- Peaks point up
- CH2
- Peaks point down
- Quaternary C
- Signal absent
- Use
- Carbon multiplicity assignment without a 2D experiment
Common questions
Why does DEPT 135 not show quaternary carbons?+
The technique relies on polarization transfer from directly attached protons, and a quaternary carbon has no attached hydrogen to transfer that polarization from, so it gives no signal in the DEPT spectrum even though it appears in the standard 13C spectrum.
How is DEPT 135 used alongside a standard 13C spectrum in casework?+
The examiner overlays the DEPT result on the full 13C spectrum: any peak present in the 13C spectrum but absent from DEPT is assigned as quaternary, while the up or down phase of the remaining peaks sorts them into CH3/CH versus CH2, speeding up structural confirmation of a questioned compound.
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