Spectroscopy Tutorial: Alkynes

IR Spectroscopy

The band at 2260-2100 is highly distinctive of a carbon-carbon triple bond stretch. Also note the C–H stretch of an alkyne from 3330–3270.

• –C(triple bond)C– stretch from 2260-2100 (weak)
• –C(triple bond)C–H: C–H stretch from 3330-3270
• –C(triple bond)C–H: C–H bend from 700-610

NMR Spectroscopy

An alkyne proton shows up from 2–3 ppm.

Example

Example 15