Photosolvolysis of bulky (4-hydroxyphenyl)naphthalene derivatives.
Six new naphthylphenols , bearing bulky hydroxymethyl substituents on the naphthalene, were synthesized and their photoreactivity was investigated by preparative irradiation, fluorescence measurements, and laser flash photolysis. All derivatives (in S1) undergo deprotonation of the phenolic OH in the aqueous solution. Also, fluorescence quenching with HClO4 in the pH range 2-4 indicates that can be protonated in S1. Formation of QMs most probably takes place sequentially, triggered by the phenol deprotonation. However, with the present data, a mechanism that involves simultaneous deprotonation and the loss of OH(-) cannot be ruled out. Photodehydration takes place only for , , and , delivering the corresponding QMs which react with nucleophilic solvents giving the corresponding photosolvolysis products. The other less likely option for the formation of the observed solvolysis products from , , and may involve some radical species. Photodehydration of and was not observed which may be due to the anticipated high energy of the corresponding sterically-congested and . The most efficient photosolvolyses were observed for the 2,6-substituted naphthalenes.
Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia. nbasaric@irb.hr.
Dani
D
Skalamera
Kata
K
Mlinarić-Majerski
Lidija
L
Uzelac
Marijeta
M
Kralj
Peter
P
Wan
Nikola
N
Basarić
D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry* / Q000528:radiation effects*; D055668:Photochemical Processes / Q000528:radiation effects*; D010782:Photolysis / Q000528:radiation effects; D012995:Solubility / Q000528:radiation effects
D009281:Naphthalenes