Photochromism single crystals

Dynamics of Surface Morphology Changes of Photochromic Single Crystals... 

Naumov P, Yu P, Sakurai K (2008) Electronic tera-order stabilization of photoinduced metastable species structure of the photochromic product of spiropyran determined with in situ single crystal X-ray photodiffraction. J Phys Chem A 112 5810-5814... 

All the 311 molecules adopt a P-helical conformation in the central hexatriene part (this crystal is named (P)-311 NpF). Single crystals with the opposite chirality, (M)-311 NpF, in which 311 is in an M-helical conformation, were also obtained from the same sample batch. The chiral cocrystals underwent photochromism. Upon irradiation with 365 nm light, the colorless crystal turned blue. 

Yamamoto, S., Matsuda, K., and Irie, M. (2003) Absolute asymmetric photocyclization of a photochromic diarylethene derivative in single crystals, Angew. Chem. Int. Ed., 42, 1636-1639. 

In addition, most photochromic reactions are performed in solution. Generally, the practical uses require them to undergo photochromism in solid films or even at the level of single molecules. Therefore, it is desirable to develop new photochromic dithienylethene-phthalocyanines and their analog systems such as single crystals and polymers. 

Surface state densities of the order of 10 cm are commonplace for semiconductor electrodes of the sort considered in previous sections of this chapter. These translate to equivalent volume densities of 10 cm for nanocrystalline films. Such high densities enhance light absorption by trapped electrons in surface states, giving rise to photochromic and electrochromic efiects [297-299] (see below). Unusually high photocurrent quantum yields are also observed with sub-band-gap light with these photoelectrode materials. Corresponding sub-band-gap phenomena are rather weak and difficult to detect with single crystal counterparts. 

Irie, M., Kobatake S., and Horichi M. Reversible surface morphology changes of a photochromic diarylethene single crystal by photoirradiation- Science 2001, 291, 1769-1772. 

Use Photography, photometry and optics, batteries, photochromic glass, silver plating, production of pure silver, antiseptic. Single crystals are used for infrared absorption cells and lens elements, lab reagent. 

Chapter 7 (Structural Studies by X-ray Diffraction). The geometric parameters of photochromic compounds have been determined by X-ray diffraction on single crystals and yield interesting correlations with photochromic behavior (colorability, thermal bleaching rates, or absorption spectrum of the colored species). More intensive studies have been carried out on members of the spiropyran series (indolinospiropyrans), examining both closed spiranic forms and permanent merocyanines. The latter served as models of open photomer-ocyanines, the transient species produced by UV irradiation of spiropyrans. 

Kuroki, L., Takami, S., Shibata, K. and Irie, M. (2005) Photochromism of single crystals composed of dioxazolylethene and dithiazolylethene. Chem. Commun., 6005-6007. 

Photochromism of diarylethene single crystals Crystal structures and photochromic performance. Chem. Commun., 3895-3905. 

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