CIDNP assisted assignment of carbon-13 NMR lines in α-tetralone and α-indanone

The reversible abstraction of hydrogen from benzene-1,3,5-triol by photoexcited α-tetralone or α-indanone in solutions of methanol leads to CIDNP in the ¹³C NMR spectra of these compounds. The information gained from the phase of the polarization in the CIDNP spectra is used to resolve the ambiguities in the assignment of the ¹³C NMR lines for α-indanone and α-tetralone, arising from conflicting literature data. Chemical shifts for both compounds in methanol are reported. 2′-Methylacetophenone does not exhibit CIDNP in the ¹³C spectrum under similar conditions.