Optically detected magnetic resonance of α-deuterated 2-indanone

When 2-indanone is optically pumped into the phosphorescent triplet state, the excitation remains localized on the carbonyl moiety. Hence, the hydrogens at the α carbons play an important role in the electronic relaxation. Subtle perturbations can be introduced by exchanging these slightly acidic hydrogens with deuteriums. Various deuterated 2-indanone molecules were synthesized and the properties of their phosphorescent triplet state were experimentally determined by optically detected magnetic resonance (ODMR). Theoretical calculations showed that the shifts in the observed zero-field splitting parameters as a function of deuteration are a result of spin–orbit coupling. Finally, unexpected features in the ODMR spectra are explained in terms of the moleculeʹs crystal structure.