Abstracts

In this work, we present a new phenoxy-triggered 1,2-dioxetane based on hydroxylated TEPI derivatives, utilizing methodologies our research group has explored with hydroperoxides and silylperoxides derived from triphenylimidazoles. The selected TEPI 1,2-dioxetanes vary in the position of the silyl-protected hydroxy group, featuring ortho, meta, and para substitutions. We studied their deprotection and chemiluminescence (CL) kinetics and proposed a possible mechanistic rationalization for the effect of the phenoxy position on chemiexcitation efficiency. Despite their low stability, which complicates purification, we successfully used the 1,2-dioxetanes in kinetic chemiluminescence assays. For these peroxides, our hypothesis is that an intramolecular electron transfer from the sp² nitrogen atom of the imidazolyl system to the O–O bond of the peroxidic ring occurs, influenced by the charge density of the phenolate group, during the intramolecularly catalyzed decomposition of these 1,2-dioxetanes. It appears that the meta-oriented derivative exhibits higher chemiexcitation efficiencies due to the so-called 'meta effect,' previously observed with other phenoxy-triggered 1,2-dioxetanes. The decomposition of the ortho and para-substituted derivatives may proceed through a more accessible pathway, leading to products in the ground state. Future computational studies exploring the influence of electronic properties and the position of substituents on CL will be invaluable for rationalizing the intramolecular CIEEL panorama. This could significantly enhance our understanding of other light-emitting systems and compounds.