Effect of co-adsorbed water on photodimerization and photooxygenation of 4-methoxystyrene included in NaY

Article abstract of DOI:10.1016/S0040-4039(99)00510-9

Irradiation of 4-methoxystyrene (1) in zeolite NaY under vacuum, dry oxygen, and wet air yielded dimers and oxygenation products dependent on the atmosphere and co-adsorbed water. Head-to-head cis- and trans-cyclobutane dimers of 1 were produced at the isomer ratio of 91/9 under vacuum through excimer of 1 and 38/62 under wet air through cation radical of 1, respectively. However, 4-methoxybenzaldehyde was a primary product under dry oxygen at the expense of production of the dimers (c/t = 81/19). These results show significant differences in the photochemical behavior of 1 in solution and in NaY.