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Irreversible photochromism

A class of crown spirobenzopyrans 10 exhibit thermally irreversible photochromism only in the presence of alkali-metal cations (Scheme 3). The favored complexation between 10 and lithium cation was thus revealed by the effect of lithium salt on the electronic absorption spectra of 10. Lithium complexation was also corroborated on the basis of FAB mass experiments. Before addition of Lil to 10, ion peaks for MH, [M + Na] and [M + K] were detected after the addition the signals decreased, while a peak for [M + Li]+ appeared (Figure 10) . [Pg.217]

Recently (08JPCA4765), new thermally irreversible photochromes 156-159 containing silicon or phosphorus atoms in the five-membered bridge have been synthesized. They have fluorescence in the closed forms, whereas their open forms do not exhibit fluorescence. Hence, they are highly promising for the nondestructive readout of optical information (07MI1). Their synthesis from 2- and 3-substituted butadienes was documented (09NJC1357). [Pg.34]

Compound 311 underwent a thermally irreversible photochromic reaction in solution (08JCS(CC)335). Upon alternate irradiation with UV and visible light, a hexane solution of 311 reversibly changed its color from colorless to bluish purple due to the isomerization between the open- and closed-ring isomers, 311 and 312. [Pg.227]

Such thermally irreversible photochromic chromophores represent the other class, classified as P-type (photochemically reversible type). Although many photochromic compounds have been so far reported, P-type chromophores are very rare. Only two families, furylfulgide derivatives and diarylethene derivatives, exhibit this reactivity.19 101 The photogenerated isomers of these derivatives are thermally stable and never revert to their initial isomers even at elevated temperatures (-100 °C). The thermally stable photochromic compounds offer potential for various applications in photoswitching and memory devices. [Pg.38]

Since 1981, when Heller and co-workers synthesized a furylfulgide 2,141 fulgides have included representatives of thermally irreversible photochromic compounds among their number. Fulgides known until then had been thermally reversible. Three major modifications were made to the fulgide structure ... [Pg.109]

Application of a thermally irreversible photochromic compound in an optical memory medium requires that several conditions should be satisfied. Among them, the development of a non-destructive readout method is a difficult problem. Exposure to light that might be absorbed should be avoided, because it causes destruction of memory. [Pg.110]

T. Yoshida and A. Morinaka, Irreversible photochromism of spiropyran films at low temperatures, J. [Pg.80]

The synthesized fulgenates were thermally irreversible photochromic compounds. Their photochromic reaction is shown in Scheme 26. [Pg.181]

Y. Yokoyama, T. Serizawa, S. Suzuki, Y. Yokoyama, and Y. Kurita, Fulgenolides thermally irreversible photochromic lactones with large quantum yields of photoreactions, Chem. Lett., 1995, 17-18. [Pg.201]

Y. Yokoyama, K. Sugiyama, S. Yamada, H. Takimoto, and Y. Kurita, Fulgenates. A new class of fulgide-related irreversible photochromic system, Chem. Lett., 1994, 749-752. [Pg.201]

I. Cabrera, A. Dittrich, and H. Ringsdorf, Thermally irreversible photochromic liquid crystal polymers, Angew. Chem. Int. Ed. Engl, 30, 76-78 (1991). [Pg.205]

Diarylethenes having thiazole rings also undergo thermally irreversible photochromic reactions.8 Introduction of a trifluoromethyl group at the 4-position of the thiazole ring is effective in increasing the thermal stability of the closed-ring form. [Pg.209]

M. Irie and M. Mohri, Thermally irreversible photochromic systems. Reversible photocyclization of diarylethene derivatives, J. Org. Chem. 53, 803-805 (1988). [Pg.221]

K. Uchida, T. Ishikawa, M. Takeshita, and M. Irie, Thermally irreversible photochromic systems. Reversible photocyclization of l,2-bis(thiazolyl)perfluorocyclopentenes, Tetrahedron, 54, 6627-6638 (1998). [Pg.221]

Furyl fulgide 20 (Eq. (7)) is the first known example of thermally irreversible photochromic molecules. Although phenyl fulgides such as 21 have been known to show photochromic reactions, photogenerated dihydronaphthalene derivatives such as 21C (Eq. (8)) are thermally unstable and undergo irreversible side reactions, i.e., 1,5-hydrogen shifts to produce 1,2-dihydonaphthalene derivatives [23-26]. This... [Pg.3403]

Stilbene derivatives also undergo thermally irreversible photochromic reactions. Among the derivatives, the thioxanthenes 41 and 42 are of the most interest from the viewpoint of their apphcation to memory media [42-44]. [Pg.3410]

K. Uchida, S. Nakamura, and M. Me, Thermally irreversible photochromic systems. Substituent effect on the absorption wavelength of ll,12-dicyano-5a,5b-dihydro-5a,5b-dimethylbenzo[l,2-fe6,5-i bis l benzothiophene, Hull. Chem. Soc. Jpn. 65, 430-435 (1992). [Pg.257]

Nakamura, S. and Irie, M. (1988) Thermally irreversible photochromic systems. A theoretical study./. Org. Chem., 53, 6136-6138. [Pg.174]

Photochromic reactions of cw-l,2-diarylethenes are the extension of photochemical electrocyclization of cw-stilbene, which yields dihydrophenanthrene. When the aromatic stabilization energy (aromaticity) of at least one aryl group is low (such as furan, thiophene, benzothiophene) and the nonhydrogen substituents are located on the ring-forming carbon atoms, the thermally irreversible photochromism is observed. When the aromaticity of both aryl groups are high (such as phenyl, indolyl, or pyrryl), the diarylethene is thermally reversible [31]. [Pg.242]

Complete erasing of the recording information can be completely erased by ultraviolet illumination. Dual-use chromophore molecules allow to write both irreversible photochromic and erasable photorefractive holographic gratings into the same storage volume. ... [Pg.45]

K. Rameshbabu, A. Urbas, Q. Li, Synthesis and characterization of thermally irreversible photochromic cholesteric liquid crystals. J. Phys. Chem. B 115, 3409-3415 (2011)... [Pg.175]

S. M. Shrestha, H. Nagashima, Y. Yokoyama, Y. Yokoyama, Synthesis of novel thermally irreversible photochromic l-aryl-l,3-bntadiene derivatives. Bull. Chem. Soc. Jpn., 76, 363-367 (2003). [Pg.810]


See other pages where Irreversible photochromism is mentioned: [Pg.19]    [Pg.26]    [Pg.52]    [Pg.1150]    [Pg.120]    [Pg.3394]    [Pg.3397]    [Pg.3409]    [Pg.258]    [Pg.357]    [Pg.324]    [Pg.693]    [Pg.66]    [Pg.803]    [Pg.805]   
See also in sourсe #XX -- [ Pg.84 ]




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