6-Phenoxy-5,12-naphthacenequinone

To determine the photoinduced structure, the orange crystals that were formed after irradiation of benzene solutions of 6-phenoxy-5,12-naphthacenequinone were used.46 It turned out that the elemental composition of the photoinduced form coincided with the ana-quinone composition. In addition, the interaction of 6-phenoxy-5,12-naphthacenequinone with ammonia and aniline in benzene resulted in the formation of compounds that were identified as derivatives of ana-naphthace-nequinone by the counter synthesis. The ana structure of the photoinduced form was supported by the similarity of the absorption spectrum of the ana form to the spectra of unsubstituted and 5-bromo derivatives of 6,12-naphthacenequinone46 as well as by the analysis of the IR spectra of initial and photoinduced forms of 6-phenoxy-5,12-naphthacenequinone. 4... 

Figure 7.8. Absorption spectra of 6-phenoxy-5,12-naphthacenequinone in toluene (C - 1.02 x 10 4 mol/liter)43 before (1) and after (2) irradiation (Xtxc = 405 nm).

A comparative study of the photochromic transformations for 6-phenoxy-5,12-naphthacenequinone in toluene and polymer matrix showed that the value of the quantum yields was unchanged with a polymer binder in place of toluene. 61 Quantum yields for direct and back photoreactions were equal to cpB= 0.3 and (Pa = 0.005 under UV light and q>A = 0.005 under visible irradiation. 

Photochromism resulting from photoinduced reversible arylotropy (para-ana phototransformations) was observed for the quinonemethide analog of phenoxy-naphthacenequinone (Scheme 21).37,39... 

A. Zelichenok, F. Buchholz, E. Fischer, J. Katner, V. Krongauz, H. Anneser, and C. Brauchle, Photochemistry and multiple holographic recording in polymers with photochromic phenoxy-naphthacenequinone side groups, J. Photochem. Photobiol. A Chem. 76, 135-151 (1993). 

Bom, R., Fischer, W., Heger, D., Tokarczyk, B., Wirz, J., Photochromism of Phenoxy naphthacenequinones Diabatic or Adiabatic Phenyl Group Transfer , Photochem. Photobiol. Sci. 2007, 6, 552 559. 

Chloro-5,12-naphthacenequinone was used for the synthesis of 6-[4(2-(4-hydroxyphenyl)-isopropyl]- and 6-[4-(potassium sulfophenylazo)phenoxy]-5,12-naphthocenequinones (IIIB)55 as well as other derivatives of 11-phenoxynaphtha-cene-5,12-quinone.53... 

Phenoxy-substituted 2H, 8 -naphtha [l,2,3-de]-benz[/j]-2,8-quinolinedione (IIIC, R2 = hydrogen, R3 = CH3) was synthesized by cyclization of TV-chloro-acetyl-6-aminonaphthacenequinone in pyridine to the corresponding naphthacenepyrido-nyl-3-pyridinium chloride, with the subsequent reductive elimination of the pyridi-nium residue.39 The 3-acetyl derivative was obtained by the interaction of 6-amino-ll-chloro-5,12,naphthacenequinone with acetic anhydride in phenol in the presence of anhydrous sodium carbonate.39... 

Phenoxynaphthaceno[12,ll[6c]-2,8-pyrandione (HIE) was obtained from 6-phenoxy-5,ll-naphthacenequinone (Scheme 6), which was synthesized from... 

Similar to 1-phenoxyanthraquinones, photochromism is absent in 6-dimcthv-lamino and 6-phenylamino derivatives of ll-phenoxy-5,12-naphthacenequinone. Photochromic properties are absent for ll-phenoxyphenol-6-amino-5,12-naphtha-cenequinone because of steric hindrances to forming the transient spirocomplex (see Scheme 9) during photochromic transformation of this compound. 

One can see from Table 7.8 that there was a distinct dependence of the maxima of the initial and photoinduced forms on the nature of the substituent in the naphthacenequinone ring. Note that the absorption spectra of 11-phenoxynaphtha-cene-5,12-quinones and nonphotochromic para-quinone without the phenoxy group were quite similar.46 The linear correlation r = 0.992) between the position of the... 

Table 7.9 shows that the positions of the long-wavelength absorption bands were virtually independent of the substituent nature in the phenyl ring of the phenoxy group for the photochromic compounds without and with 6-amino substituents in a naphthacenequinone nucleus.43,52 However, the introduction of 6-amino substituents resulted in the shift of the absorption bands of the initial and photoinduced forms to the visible spectral range (Table 7.9) and their substantial overlapping (Figure 7.9). 

Absorption bands of the initial and photoinduced forms of 6-phenoxy-5,13-pentacenequinone (Figure 7.13) were slightly shifted (by 10 nm) to the red compared with 11 -phenoxy-5,12-naphthacenequinone.57... 

The presence of the electron-donor substituents in the migration group of 11-aryloxy derivatives of 6-amino-5,12-naphthacenequinone was favorable for photochromic transformations.52 Aryloxynaphthacenequinones with electron-acceptor substituents in the phenoxy group were photoisomerized less efficiently. 

The efficiencies of the photochromic transformations for phenoxypentacene-quinone and the derivatives of phenoxyphthaloylpyrene match the photocoloring and photobleaching efficiencies for the phenoxy derivatives of naphthacenequinone.57... 

Yu. E. Gerasimenko, A. A. Parshutkin, N. T. Poteleshenko, V. P. Poteleshenko, and V. V. Romanov, Photochromism of peri-aryloxy-p-quinones. Determination of molecular absorption coefficients for 6-phenoxy-5,ll-naphthacenequinones, Zh. Prikl. Spektr. 30, 954-956 (1979) (Russ.). 

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