Abstract: Three dichromogenic compounds containing both phenoxynaphthacenequinone and azobenzene photochromes, 6-[4-(phenylazo)phenoxy]-5,12-naphthacenequinone(5), 6-[4-(p ethoxyphenylazo)phenoxy]-5,12-naphthacenequinone(6)and 6-[4-(p nitrophenylazo)phenoxy]-5,12-naphthacene quinone(7), were synthesized by reacting-6 chloro 5,12 naphthacene quinone with 4 hydroxyazobenzene and its derivatives. It was found that the phenoxynaphthacenequinone photochromes of all these dichromogenic compounds showed slight UVinduced photochromism. Based on the irreversible reaction of ammonia with the colored phenoxy ana naphthacenequinone, the concentrations of the ana forms of 5 and 6 in DMSO at the photostationary state(PSS)under 365 nm irradiation were estimated to be only 22% and 17% respectively. The results indicate the strong effect of phenylazo group on the photochromic properties of phenoxynaphthacenequinone photochrome. On the other hand, unlike the 4 hydroxyazobenzene precursors, the cis isomers of azobenzene photochromes in the dichromogenic compounds were relatively stable in DMSO solution.

Key words: dichromogenic compound, phenoxynaphthacenequinone, azobenzene, photochromism