79792-94-2Relevant articles and documents
Synthesis, Thermal Stability, and Chemiluminescence Properties of the Dioxetanes Derived from 1,4-Dioxines
Adam, Waldemar,Peters, Eva-Maria,Peters, Karl,Platsch, Herbert,Schmidt, Ernst,et al.
, p. 3920 - 3928 (2007/10/02)
Photosensitized oxygenation of benzo- and naphtho-1,4-dioxins 3 afforded the corresponding 1,2-dioxetanes 4 in moderate to good yields.Ene products 7 were obtained in those cases in which the 1,4-dioxins 3 bear alkyl substituents.Thermal decomposition of the 1,2-dioxetanes 4 afford the corresponding diesters 5 essentially quantitatively.The X-ray crystal structures of the dioxetanes 4g, 4h, and 4j indicate that the four-membered rings are all essentially planar.These dioxetanes exhibit surprisingly similar thermal stabilities; the free energies of activation (ΔG(excit.)) at 298 K fall within 26 +/- 1 kcal/mol, the enthalpies of activation (ΔH(excit.)) within 24 +/- 1.5 kcal/mol, and the entropies of activation (ΔS(excit.)) within -6 +/- 2 eu.In their chemiluminescence properties they are inefficient sources of chemienergized, electronically excited diester products.The singlet excitation yields (ΦS) range between 0.0001percent and 0.003percent and the triplet excitation yields (ΦT) between 0.01percent and 3.5percent.They represent typical dioxetanes in that preferentially triplet excited carbonyl products are chemienergized.
