Naphthol and 1-Aminopyrene

While HAN shows an ESIPT reaction between two groups both located on the molecular frame of the dye and does not need solvation for the occurrence of internal proton motion, 1- and 2-naphthol, which are among the most studied aromatic systems, show an excited-state intermolecular proton transfer to the medium (water, alcohols) [88-96]. The produced anionic structure emits at the blue side of the normal form. The effects of CD on the intermolecular proton-transfer reaction from 1-naphthol (1-NP) [97, 98] to water and from water to 1-aminopyrene (1-AP) [98] have been studied by emission spectroscopy. For 1-NP in pure water, the decay of the 360 nm emission band (that of the neutral reactive species leading to the anionic one emitting at the blue side, 460 nm) was fitted with a 36 ps exponential component [98]. In the presence of (S-CD, the decay at 370 nm needed two exponential functions with time constants of 700 ps (75%) and 1600 ps (25%) [98]. The average time constant for deprotonation of 1-NP in the presence of (S-CD (1 1 

For 1-AP, the rate of the proton-transfer reaction from water to the dye was found to increase upon formation of 1 1 complexes involving yS-CD [98]. To explain this observation, the authors suggest using geometrical factors for the confined structures (Fig. 7.5) which influence the dynamics of the proton-transfer reaction. 

Femtosecond Studies of Proton Transfer in Cyclodextrin Complexes 

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The first studies of the photoprotolytic dissociation of 1-naphthol, 2-naphthol and 1-aminopyrene cation in micellar solutions were made by Klein and Hauser [116] and also by Weller and SeUnger [117,118] who have shown that the photoprotolytic dissociation slows down in anionic micelles. Fendler [119] observed the photoprotolytic dissociation of 1-hydroxypyrene-trisulfonate in CTAB micelles. The inhibition of dissociation was explained in terms of the relatively low polarity and high microviscosity of the micellar phase [116-119] and also the effect of the negative micellar potential. 

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