The effect of meta versus para substitution on the efficiency of chemiexcitation in the chemically triggered electron-transfer-initiated decomposition of spiroadamantyl dioxetanes.
A similar viscosity dependence of the CIEEL efficiencies for the para- and meta-substituted spiroadamantyl dioxetanes 1 has been observed, which implies that an electron-transfer mechanism operates through solvent-caged species for both regioisomers. The pronounced difference in the chemiexcitation yields for the meta- and para-substituted dioxetanes is rationalized in terms of the much larger (ca. 200-fold) rate constant for the electron back-transfer (BET) step to afford the excited meta CIEEL emitter. An in-depth kinetic analysis of the viscosity effect on the excited-state generation for the para versus meta regioisomers supports this conclusion.
Adam
W
W
Institut für Organische Chemie, Universität Würzburg, Germany. adam@chemie.uni-wuerzburg.de
Trofimov
A V
AV
D000218:Adamantane / Q000031:analogs & derivatives* / Q000737:chemistry*; D004579:Electron Transport; D008163:Luminescent Measurements; D013141:Spiro Compounds / Q000737:chemistry*; D013237:Stereoisomerism
D013141:Spiro Compounds; D000218:Adamantane