D. Reyman et al., PHOTOCHEMICAL AND SONOCHEMICAL REACTIONS OF NORHARMANE, Journal of photochemistry and photobiology. A, Chemistry, 98(1-2), 1996, pp. 39-44
In this work, a study on the photochemical and sonochemical behaviour
of norharmane in halomethane media (dichloromethane, chloroform, carbo
n tetrachloride and dibromomethane) is presented. When solutions of no
rharmane in these media are irradiated with UV light or sonicated with
ultrasound at 20 or 50 kHz, the cationic species of norharmane appear
s in solution. In order to explain the formation of this species by a
UV radiation effect, a exciplex (charge transfer complex) between norh
armane and halomethane has been proposed. The formation rate constants
of the exciplex were calculated using fluorescence quantum yields and
lifetime values. The sonochemical formation of cationic species does
not occur by formation of a charge transfer complex between norharmane
and halomethane. In this paper, we report that an initially neutral m
edium can quickly develop acidity in a few minutes of exposure in a co
nventional bath to ultrasound.