ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 22, Number 1
JKCSEZ 22(1)
February 20, 1978 

The luminescence of N-methyllutidone is studied in ethanol matrix at 77。K. No fluorescence is observed but a strong phosphorescence with the quantum yield of 0.1 and the lifetime of 0.2 sec is recorded. An unusually high triplet energy of 85.1 kcal/mole is determined for the compound from the O-O band of phosphorescence. The cis ↔ trans photoisomerization of high triplet energy olefins such as 2-hexene and trans-1,4-dichlorobutene-2 is efficiently sensitized by N-methyllutidone substantiating the high triplet energy of the compound. The negative polarization of O-O band reveals the emitting triplet state to be (π,π*)3 state. Alkaline metal salts such as lithium chloride enhances the phosphorescence intensity through cation-N-methyllutidone coordination widening the gap between (π,π*)3 and (n,π*)3 states.