SYNTHESIS AND PHOTOCHROMISM IN SOLUTION OF PHENOXYNAPHTHACENEQUINONE DERIVATIVES

Two new phenoxynaphthacenequinone derivatives, 6-[4-(2-(4-hydroxypheny l)isopropyl)phenoxy] -5,12-naphthacenequinone (7) and 6-[4-(potassium sulfophenylazo)phenoxy]-5,12-naphthacenequinone (8), were synthesized, and their photochromism in solution was investigated and compared wit h that of 6-phenoxy-5,12-naphthacenequinone (1). On the basis of the s pectral data and the selective irreversible reaction of ammonia with t he colored phenoxy-ana-naphthacenequinone, the concentrations of the a na forms at the photostationary state (PSS), achieved by 365 nm UV irr adiation, and the molar extinction coefficients of the pure ana forms at 481-482 nm of compounds 1, 7 and 8 in dimethylsulfoxide (DMSO) were found to be 83 mol.% and 1.70x10(4) mol(-1) dm(3) cm(-1), 82 mol.% an d 1.62x10(4) mol(-1) dm(3) cm(-1) and 16 mol.% and approximately 1.34x 10(4) mol(-1) dm(3) cm(-1) respectively; the absorption spectra of the colored ana forms of 7 and 1 in DMSO were estimated; the rate;constan ts of photoconversion induced by 365 nm light were obtained. The resul ts show the strong effect of the structure of the phenoxynaphthacenequ inones on their photochromism in solution. In addition to DMSO solutio n, compound 7 exhibited normal photochromism in toluene, benzene, chlo roform and a DMSO-ethanol mixed solvent, but not in dimethylformamide (DMF) in which a photoinduced reaction occurred between 7 and DMF or i mpurities.