Photoreduction of 3,7-diaminophenoxazinylium chloride (‘oxonine’) by iron(II). A model system for singlet-state driven photogalvanic cells

Complexation and Fluorescence of Tricyclic Basic Dyes Encapsulated in Cucurbiturils

“…In the case of pyronine Y, the complexes with CB [7] and CB [8] have a one-to-one and three-to-one stoichiometry, respectively. The binding constants for CB [7] complexes range from 3.07 10 6 to 1.70 10 7 m…”

“…The presence of a positive charge as well as the amino substituents and the molecular dimensions should make these cationic dyes adequate to form stable complexes with CBs of the appropriate size. Precedents reporting the encapsulation of some of these dyes in CB [7] can be found in the literature. [22,23] [a] P. Montes-Navajas, Dr. A.…”

“…[22,23] [a] P. Montes-Navajas, Dr. A. Corma Tricyclic basic dyes (proflavine, acridine orange, pyronine, pyronine Y, oxonine, thionine and methylene blue) often form one-toone or two-to-one complexes with CB [7] and CB [8], respectively. In the case of pyronine Y, the complexes with CB [7] and CB [8] have a one-to-one and three-to-one stoichiometry, respectively.…”

“…Also, as a general effect of encapsulation inside an inert matrix, a photoactive organic molecule become stabilized, often significantly increasing its persistence before undergoing photodegradation. [19] Thus, it has been reported that rhodamine 6G partially encapsulated inside CB [7] becomes stabilized to such an extent that the corresponding rhodamine 6G-CB [7] host-guest complex can be used advantageously as a laser dye. [20,21] This phenomenon is generally due to the fact that oxygen reacts with many triplet excited states resulting in the formation of singlet oxygen, and this active oxygen species can attack and degrade the organic molecule.…”

“…[7][8][9][10] Some of these dyes bear a positive charge delocalized throughout the structure. Given the shape and size of these tricyclic dyes, as well as the positive charge, they appear as suitable guest molecules to form strong host-guest complexes with cucurbiturils (CBs).…”