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CHEMICAL CHANGES LEADING TO CHEMILUMINESCENCE OF LUCIGENINE (DIMETHYLBIACRIDYLIUM NITRATE) AND OF SOME PHTHALAZINEDIONE DERIVATIVES
Author(s) -
Totter John R.,
Philbrook George E.
Publication year - 1966
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1966.tb05779.x
Subject(s) - chemiluminescence , chemistry , hydrogen peroxide , inorganic chemistry , luminol , oxygen , ammonium hydroxide , hydroxide , peroxide , redox , photochemistry , organic chemistry
— Measurements of the redox potential of the chemiluminescent compound 10,10′ dimethyl‐9,9′ biacridylium nitrate (‐0.093 V) show that it is thermodynamically possible to reduce it with hydrogen peroxide or with ammonium hydroxide in alkaline solutions at equilibrium concentrations sufficiently high to account for the observed chemiluminescence. Reduction of the compound with ammonium hydroxide takes place much more slowly than the corresponding reaction with hydrogen peroxide so that when both redox couples (O 2 /H 2 O 2 and N 2 H 4 /NH 4 OH) are present the hydrogen peroxide couple predominates if oxygen is supplied. It was shown that interference with the oxygen supply or its partial removal with nitrogen brings about an increase in chemiluminescence intensity in NH 4 OH while increasing the concentration of oxygen diminished the intensity. 5‐amino 2,3 phthalazine 1,4 dione (luminol) also appears to undergo a reduction following a two step oxidation. This is shown by the fact that when oxygen was supplied the chemiluminescence intensity was found to be directly proportional to the OH ‐ concentration while a typical titration curve with p K 11.7 is exhibited by the intensity when the oxygen supply is limited in mixtures of luminol and peroxydisulfate. The peroxide presumably arises in the first oxidation step. Amino peroxyphthalic anhydride is suggested as an intermediate which is reduced to the aminophthalate ion, the presumed emitter in the chemiluminescence.