Complexes photochromic

Three different 6-nitroBIPS having as additional substituents l -phenyl, 1 -phenyl-8-methoxy, and 5 -chloro-8-methoxy, exhibited complex photochromic and... 

A spironaphthoxazine derivative incorporating a monoaza-12-crown-4 entity at the 5 -position has been prepared by Kimura el al.19 It is a light-resistant, cation-complexable photochromic compound. 

K. Kimura, M. Kaneshige, T. Yamashita, and M. Yokoyama, Cation complexation, photochromism, and reversible ion-conducting control of crowned spironaphthoxazine, 7. Org. Chem. 59, 1251— 1256 (1994). 

Other Uses. Photochromic glass contains silver chloride (80) and silver molybdate [13765-74-7] (81) (see Chromogenic materials). An apparatus coated with silver nitrate has been described for the detection of rain or snow (82). Treatment with silver-thiosulfate complex has been reported as dramatically increasing the post-harvest life of cut carnations (83). Silver sulfate has been used in the electrolytic coloring of aluminum (84). Silver sulfate also imparts a yellowish red color to glass bulbs (85). 

Thin films of photochromic silver complex oxides were prepared by anodic oxidation of silver metal films (15). Complex oxides, such as Ag2V04, Ag SiO, and Ag2P04, darkened by exposure to visible light, but required heating to 150—250°C for thermal bleaching. 

Reaction Dynamics Studies on Crystalline-State Photochromism of Rhodium Dithionite Complexes 487... 

The photochromism of the spiropyran depends on the structure of heterocyclic parts, the medium such as solvent or plastic films, temperature, and light energy. Though the actual mechanisms may be more complex, a simple photochromic behavior in the spiropyrans is illustrated in Scheme 1. Initially, a spiropyran is excited by photoirradiation, and then a cisoid isomer arises after dissociation of the C—O bond. Finally, the cisoid form changes to the thermodynamically stable transoid form. The equilibrium between the cisoid and transoid forms largely depends on the substituent groups. The reversal of the colored form to the colorless spiropyran occurs by thermal or photochemical energy. More detailed mechanisms will be described in Section 1.2.1.6. 

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) . 

Other imsymmetrical compounds include dipolar photochromic Zn(II) dipyridyl complexes 35 with nonlinear optical properties (08AG(E)577),... 

Nakai H, Mizuno M, Nishioka T, Koga N, Shiomi K, Miyano Y, Irie M, Breedlove BK, Kinoshita I, Hayashi Y, Ozawa Y, Yonezawa T, Toriumi K, Isobe K (2006) Direct observation of photochromic dynamics in the crystalline state of an organorhodium dithionite complex. Angew Chem Int Ed 45 6473-6476... 

The bisbarium complex of azobis(berizo-18-crown-6) ether 28 exhibits catalytic properties that can be reversibly activated-deactivated by light-induced changes in molecular geometry [32]. The azobenzene unit is a well-known photochromic [33], often used in the construction of molecular switches [34]. 

Silver was one of several metals found to give a photochromic primary complex. In THF it was normally yellow (Ama = 470 nm). Activation at 450 nm, i.e. in the region containing the normal visible absorption band, generated a violet solution with in the 570-620 nm... 

Aniline, A -(salicvlaldehydo)-photochromism, 718 Aniline, TV-sulfinyl-metal complexes, 804 Anils... 

Phosphorus-containing macrocycles, 990, 996, 998 macrocychc effect, 1002 ring size, 1003 stereochemistry, 1003 Phosphorus heterocycles transition metal complexes, 1041 Phosphorus ligands, 989-1061 ir-acid series, 1033 bonding, 1030-1041 cone angle concept, 1012 trigonal bipyramidal complexes, 1036 Phosphorus oxychloride metal complexes, 500 Phosphorus ylides transition metal complexes, 1056 Phosphorylation biological, 978 Phosvitin, 975 Photochromism... 

The mechanism of photochromism in spiropyrans and the effect of temperature, viscosity, solvent, and reversing radiation have been studied intensively by Hirshberg et al. (51,54-59). Many of the major features of the photo and thermal processes are now well understood but the complexity of the equilibria involved complicate complete... 

HgSHgX2 Complexes. Although the exact mechanism of the photochromism of 2HgS-HgX2 type complexes is still somewhat in doubt, Rao et al. (67) suggested that such dithiotrimercury (II) salts... 

HgS Hgl2, Takei observed microscopic black spots which he attributed to colloidal mercury. Heating facilitates reversion of the crystal to the yellow form which is explained as a vaporization of the Hg deposits. If this mechanism proves to be correct, this process is merely a permanent photochemical decomposition of the complex and not a true photochromic phenomenon. 

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