Magnesium methoxide-induced chemiluminescent decomposition of bicyclic dioxetanes bearing a 2'-alkoxy-2-hydroxy-1,1'-binaphthyl-7-yl moiety.

Bicyclic dioxetanes 2a-c bearing a 2'-alkoxy-2-hydroxy-1,1'-binaphthyl-7-yl moiety were effectively synthesized and their base-induced chemiluminescent decomposition was investigated by the use of alkaline metal (Na(+) and K(+) ) or Mg(2+) alkoxide in MeOH. When 2a-c were treated with tetrabutylammonium fluoride (TBAF) in dimethyl sulfoxide (DMSO) as a reference system, they showed chemiluminescence as a flash of orange light (maximum wavelength λmax (CL)  = 573-577 nm) with efficiency Φ(CL)  = 6-8 × 10(-2) . On the other hand, for an alkaline metal (Na(+) or K(+) ) alkoxide/MeOH system, 2a-c decomposed slowly to emit a glow of chemiluminescence, the spectra of which were shifted slightly toward red from the TBAF/DMSO system, and Φ(CL) (= 1.4-2.3 × 10(-3) ) was considerably decreased. In addition, Mg(OMe)2 was found to play a characteristic role as a base for the chemiluminescent decomposition of 2a-c through coordination to the intermediary oxidoaryl-substituted dioxetanes 13. Thus, Mg(2+) increased Φ(CL) to more than twice those with Na(+) or K(+) , while it shifted λmax (CL) considerably toward blue (λmax (CL)  = 550-566 nm).
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