Organic phthalocyanines

Lelu S, Novat C, GraUlat C, et al. (2003) Encapsulation of an organic phthalocyanine blue pigment into polystyrene latex particles using a miniemulsion polymerization. Polym Int 52 542-547... 

Molecular films, ordered thin organic films in a thickness range from a few nanometers (a monolayer) to several hundred nanometers, show considerable technological promise [205, 206]. Phthalocyanine thin films have been of particular interest because of their photo and electrical responses [207-210]. However, unsubstituted phthalocyanines generally have some limitations as far as arranging and organizing phthalocyanine moieties into a desired crystal... 

A. Schmidt, L. K. Chau, A. Back, and N. R. Armstrong, Epitaxial Phthalocyanine Ultrathin Films Grown by Organic Molecular Beam Epitaxy (OMBE), in Phthalo-cyanines, Vol. 4, C. Leznof and A. P. B. Lever, eds., VCH Publications, 1996. 

Photochromic Organic Dyes. Intensive investigations into this category of substances have led to numerous patent appHcations. Copper—phthalocyanine pigments, organic dyes based on cyanine (Ricoh, Pioneer), naphthochinone (Nippon Denki), and ben2othiopyrane (Sony) (123) have been described. They did not lead, however, to any commercial use. Surveys on the possibiUties of optical data storage with photochromic dyes can be found (124,125). 

Materials. Beside inorganic materials (eg, barium chloride/fluoride crystals, doped with 0.05% samarium), transparent thermoplasts are preferred for the PHB technique, eg, poly (methyl methacrylate) (PMAIA), polycarbonate, and polybutyral doped with small amounts of suitable organic dyes, organic pigments like phthalocyanines, 9-arninoacridine, 1,4-dihydroxyanthraquinone [81-64-1] (quinizarin) (1), and 2,3-dihydroporphyrin (chlorin) (2). 

Metal-free, chloroaluminum phthalocyanine [14154-42-8] vanadyl phthalocyanine [13930-88-6], or magnesium phthalocyanines are sufficiently soluble in organic solvents and show enough bleachable absorption at 694.3 nm to serve as repeated Q-switching elements for mby lasers (qv) (180). Phthalocyanines have been used in other lasers as weU (181). 

Phthalocyanine pigments account for approximately 23% of the total worldwide organic pigment consumption of 225,000 tons. Approximately 20,000 t are used in printing inks, 10,000 t in paints, 9,000 t in plastics, 3,000 t in textiles, 7,000 t in dyes, and 2,000 t in specialty uses. Table 1 shows the worldwide distribution of cmde phthalocyanine capacity. The production history of phthalocyanine in the United States from 1980 to 1990 is given in Table 2 (161). The 1990 prices of phthalocyanine blue and green pigments were ca 11—22/kg and 21—27/kg, respectively. 

Chemical and biological sensors (qv) are important appHcations of LB films. In field-effect devices, the tunneling current is a function of the dielectric constant of the organic film (85—90). For example, NO2, an electron acceptor, has been detected by a phthalocyanine (or a porphyrin) LB film. The mechanism of the reaction is a partial oxidation that introduces charge carriers into the film, thus changing its band gap and as a result, its dc-conductivity. Field-effect devices are very sensitive, but not selective. 

Fig. 6. Classes of charge-generating dyes and pigments (a) perylenes, (b) thiapyrylium, (c) phthalocyanines, (d) squaiaines, and (e) a2o. R and Z are organic...

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