Rd. Gordon et Wkc. Park, THE 353 NM 1N-PI-ASTERISK TRANSITION OF 4H-PYRAN-4-ONE AND A DEUTERATED DERIVATIVE, Canadian journal of chemistry, 71(10), 1993, pp. 1672-1675
The 353 nm vapour absorption of 4H-pyran-4-one, and its 3,5-d2 derivat
ive, has been measured and assigned to a forbidden, 1A2 (npi) - 1A1 e
lectronic transition, with electronic origin near 28 360 cm-1, made al
lowed by vibrations involving out-of-plane ring and C-H motions. Altho
ugh the molecule remains planar upon excitation, other effects of conj
ugation on the nature of the excited state are less marked than in 2-c
yclopenten-1-one.