Fluorescence quenching of intramolecular exciplex by pyridine and formation of triple exciplex

Hydrocarbon analogs of the type II photoeliminations of ketones. Photochemistry of 1-substituted 4-phenyl-4-pentenes

“…Recrystallization from hexane gave 1.79 g (90%) of 8: nip 57-58 "C; NMR (CDC13) T 2.15 (m. 2 H, aromatics ortho to C=O), 2.68 (m,8 H, remaining aromatics), 4.73 (broad s, 1 H, C=CH), 4.90 (broad s, 1 H, C=CH), 6.97 (broad singlet with shoulders, 4 H, CH2's). This material wasdistilled togive3,39g(18%)of6,bp 137-142"C(0.25 mm).This material crystallized on standing and was recrystallized from hexane to give an analytical sample: mp 40-41 "C; NMR (CDC13) T 2.6 (m, I O H, aromatics), 7.2 (m, 3 H, C H and CH2), 8.0 (m, 2 H, CH2), 8.8 (d, J = 7 Hz, 3 H, CH3); A, , , (ethanol) 241 nm ( e 12 000), 278 ( e 810).…”