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Abstract
Our interest i directed towards tudying the photochemical and pbotophy ical propertie of some heterocyclic compound . $0 yntbe is
of some coumarin derivariv s. 7-hydroxyc .lunar in \ as used a a rtarting
mat rial to synthe is 7-allyloxycoumarin dye II. 7-propargyloxycQumarin
dye ill. Dye Twa reacted with nitrilimines [0 give the cycloadducr dyes
IVlL~’
The effect of olvenrs On the light ab orption and fluorescence
emis ion of d, e II, III also 011 th - eycloaddu dyes IV,..., were
discussed. It v a’ found that the effect of solvent polarity on the
ab orption trausirion energy, half-band width v 1’_ and oscillator
strength (f), displayed different spectral behaviour i.e, positive or
negative . olvatochromism in different solvent classes, Stoke .hifts.
fluorescence energie and fluorescence quantum ield tJlr also have been
tudied .
.Furthermore, the effect of temperature on excitation and
fluorescence spectra of dye I b wa discu sed according to Williams.
Lande! and Ferry (VlLF) equation, TI1e re ult revealed that both of
excitation and fluore cenee spe tra of tbe dye abe, \VLFequatiotl at
remperatur ranged from Tg to (Tg + lOOcC), while at temperature higher
than (Tg + 100” ) another beha iour was obser ed.
The effect of concentration on the Onere ’eeoc pectra of dye n
lind IVb [0 know the probability of fonnatiou of the excimer Or higher
aggregation in the excited tale Was tudied, The results showed that there.