EXCITED-STATE PROTON-TRANSFER FROM HYDROXYALKYLNAPHTHOLS

The excited-state proton-transfer (ESPT) reactions of 1-propyl-2-napht hol (PN), 1-(3-hydroxypropyl)-2-naphthol (HPN), and 1-(2,3-dihydroxypr opyl)-2-naphthol (DPN) in aqueous methanol solutions have been investi gated. The hydroxypropyl and dihydroxypropyl side chains have a pronou nced effect on the rate of the proton transfer and on the number of wa ter molecules involved, indicating that proton transfer in alcoholic s olvents is more complex than simple models of water clusters can accom modate. Alternative models in which a side chain facilitates the forma tion of the requisite geometry for proton transfer are discussed.