Mechanism of direct and rubrene enhanced chemiluminescence during .alpha.-peroxylactone decarboxylation

Abstract

Publication costs assisted by the Atomic Energy Commission and the Petroleum Research Fund Direct chemiluminescence measurements during the decarboxylation of the tertbutyl and dimethyl a-peroxylactones (2a and 2b) in benzene and carbon tetrachloride afforded singlet yields (a) of 4.7 X 10~4 for both excited tertbutylcarboxaldehyde and acetone, respectively. The required fluorescence quantum yields ( ) were determined to be 0.91 X 10~3 for tertbutylcarboxaldehyde and 1.2 X 10-3 for acetone.The triplet yields (ß) were estimated to be 1.5 X 10"' for tertbutylcarboxaldehyde and 5.3 X 10""2 for acetone by means of rubrene-enhanced chemiluminescence measurements. From this data the ratio in efficiencies of triplet and singlet excited state production (ß/ ) was calculated as 320 ± 55 for the tert-butyl and 115 ± 25 for the dimethyl systems, indicating a great preference for the formation of triplet excited carbonyl products in the -peroxylactone decarboxylation. On the basis of a kinetic analysis of the chemiluminescence intensities (I) and decay times (r) as a function of a-peroxylactone and rubrene concentra-5

Firefly Chemiluminescence and Bioluminescence: Efficient Generation of Excited States

“…[1,2] However, it was discovered that simple 1,2-dioxetanes produced mainly triplet excited-state products (with a small amount of singlet excitedstate products). [74] Due to various experimental problems (difficulties in synthesis, low thermal and catalytic stabilities), [81,82] the formation of excited-state products remained a mystery. The ratio between triplets and singlets do vary, depending on the structure of 1,2-dioxetanes, but triplet excited-state products were always found to be produced in higher quantities.…”

Bioluminescence and Chemiluminescence

“…More experimental data on these two dioxetanones, difficult to work with because of their short lifetimes at room temperature, is definitely called for. 1 for the less stable dioxetanones). The total yield of excited products is reported to be -17% and the ratio of triplets to singlet is - 10 [112].…”

Bioluminescence of the firefly: key steps in the formation of the electronically excited state for model systems.

“…This reaction sequence is: carbonyl compound (9). In a later report, Adam et al (10) Consistent with this mechanistic postulate, it has been observed that methylation of the phenolic oxygen of firefly luciferin makes the system nonbioluminescent although the methylated ketone itself fluoresces efficiently (12). This is the expected result if intramolecular CIEEL is responsible for light production.…”