A singlet state-driven photogalvanic cell based on the photoreduction of 3,7-diaminophenoxazinylium chloride (‘oxonine’) by iron(II)

Complexation and Fluorescence of Tricyclic Basic Dyes Encapsulated in Cucurbiturils

“…The absence of host-guest complexes between CB [5] and CB [6] is also supported by 1 H NMR data. In contrast, addition of CB [7] or CB [8] …”

“…[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.…”

“…[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).…”

“…Overall, these binding constants are four orders of magnitude higher than those reported for the same dyes in b and g-cyclodextrins. Formation of the host-guest complexes leads to an increase in the fluorescence quantum yields in the case of CB [7], while the dimeric or trimeric dye encapsulated in CB [8] are remarkably less fluorescent than the same dye in diluted solutions.…”

“…In the case of CB [8], the association constant varies between 3.24 10 13 and 2.50 10 16 m À2 . Overall, these binding constants are four orders of magnitude higher than those reported for the same dyes in b and g-cyclodextrins.…”