THE QUANTUM YIELD OF THE CHEMILUMINESCENCE OF DIMETHYLBIACRIDYLIUM NITRATE AND THE MECHANISM OF ITS ENZYMICALLY INDUCED CHEMILUMINESCENCE*

Abstract— Quantum yields for dimethylbiacridylium ion chemiluminescence based on the amount of methyl acridone formed by treatment with either H₂O₂ or with xanthine oxidasehypoxanthine in 0.01 M Na₂CO₃ at pH 10.4 and at 25°C were found to lie between 0.011 and 0.020 with an average of about 0.016.In mixed solvents containing pyridine and water or alcohol and water the emission spectrum of chemiluminescence of dimethylbiacridylium ions as well as those of diniethylbiacridene and its oxide were found to be identical with or very similar to the fluorescence of methyl acridone in the same solvent.A mechanism involving two successive two equivalent reductions of the diniethylbiacridylium ion to dimethylbiacridan followed by a radical attack and auto-oxidation leading to a compound which can undergo a reverse aldol type reaction to yield one (or two) molecule of methylacridone and one of a somewhat more reduced form is suggested.The kinetic equation relating maximum intensity of chemiluminescence to dimethylbiacridylium ion, hypoxanthine, xanthine oxidase, H⁺ and O₂ concentrations was derived from the scheme suggested and found to fit satisfactorily the data obtained from a series of experiments in which the quantum yield was also obtained.     

Light production in alkaline mixtures of reducing agents and dimethylbiacridylium nitrate.

Abstract— Kinetic studies were made of light production and 0₂ absorption elicited by treatment of dimethylbiacridylium hydroxide [D(OH)₂] with reducing agents in alkaline aqueous solutions. D(OH)2 addition stimulated O₂ uptake which proceeded with zero-order kinetics until nearly all of the O₂ or of the D(OH)₂ was converted to end products. At the termination of the reactions with fructose as reductant the D(OH)₂ was converted to methylacridone and to dimethylbiacridene each compound accounting for approximately one-half the D(OH)₂ consumed. O₂ was reduced to H₂O₂. With hydroxylamine as the reducing agent the emitted light intensity was related to the first power of the D(OH)₂ concentration and the rate of O₂ uptake to the square root of the D(OH)₂. The disappearance of D(OH)₂ in these circumstances was by a first order or pseudo-first order rate. Fructose as a reducing agent by contrast resulted in an O₂ uptake nearly independent of D(OH)₂ concentration over a range from 1 × 10^-5M-1 × 10^-4M, while the light intensity and disappearance of D(OH)₂ followed a one-half order rate. O₂ uptake was by zero order kinetics and the oxidation of fructose proceeded at the same rate as was found with ferricyanide as oxidant. The kinetics, quantum yields and temperature dependence of the fructose reactions were compared with similar reactions employing H₂O₂ as the light eliciting reagent. The results are interpreted as indicating that D(OH)₂ acts as a chain initiator in a manner analogous to better known, radical producing compounds found to accelerate hydrocarbon autooxidations.     

CHEMICAL CHANGES LEADING TO CHEMILUMINESCENCE OF LUCIGENINE (DIMETHYLBIACRIDYLIUM NITRATE) AND OF SOME PHTHALAZINEDIONE DERIVATIVES

Abstract— 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 (O₂/H₂O₂ and N₂H₄/NH₄OH) 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 NH₄OH 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.     

THE CHEMILUMINESCENCE OF CERTAIN INDOLES*

Abstract— A series of twenty-four indoles and related compounds have been examined for chemiluminescent activity in aqueous solution and in dimethylsulfoxide. Seven compounds were found to chemiluminesce in the presence of base and peroxydisulfate in aqueous solution and eleven compounds gave chemiluminescence in dimethylsulfoxide with base using oxygen as the oxidizing agent. The relative intensities have been determined. There is no clear correlation between substitution patterns and the presence of chemiluminescence in either series. Some preliminary kinetic studies have been made on the indole system. Product studies indicate that the indole is degraded by at least two different pathways and that chemiluminescent process is probably only a small fraction of the total chemical change occurring.