Novel Adsorption and Desorption Chemiluminescence of 10,10′-Disubstituted 9,9′(10H,10′H)-Biacridinylidenes in Alumina Slurries

TLDR: In this article, the effects of solvent polarity and alumina activity on the generation of chemiluminescence (CL) in an alumina slurry were investigated and the mechanism was clarified.

Abstract: 10,10′-Disubstituted 9,9′(10H,10′H)-biacridinylidene (1) has a novel chemiluminescence (CL) in an alumina slurry. The CL is yellowish green emissions I and II from the excited singlet state of adsorbed 1 onto alumina, 11*(ads), and blue emission III from the excited singlet state of 10-substituted 9(10H)-acridinone (2), 12*. In this study the effects of alumina activity and solvent polarity on the generation of those emitters were investigated and the mechanism was clarified: 1) 11*(ads) is generated by two-step electron transfers, the first electron transfer from 1 to O2 gives 1+•(ads) accompanied by adsorption of 1 and the following electron transfer from –OH and/or –O− on alumina to 1+•(ads) gives 11*(ads), and 2) 12* is generated from the reaction of 12+ and O2−•, both of which are formed during the reaction of emissions I and II. The two key compounds, 12+ and O2−•, were detected spectroscopically. O2−• in a slurry of 1, benzene, and highly activated alumina was found to be extremely stable and to ge...