Phthalocyanine compounds

Reverse saturable absorption is an increase in the absorption coefficient of a material that is proportional to pump intensity. This phenomenon typically involves the population of a strongly absorbing excited state and is the basis of optical limiters or sensor protection elements. A variety of electronic and molecular reorientation processes can give rise to reverse saturable absorption many materials exhibit this phenomenon, including fuUerenes, phthalocyanine compounds (qv), and organometaUic complexes. 

Oxidation can also occur at the central metal atom of the phthalocyanine system (2). Mn phthalocyanine, for example, can be produced ia these different oxidation states, depending on the solvent (2,31,32). The carbon atom of the ring system and the central metal atom can be reduced (33), some reversibly, eg, ia vattiag (34—41). Phthalocyanine compounds exhibit favorable catalytic properties which makes them interesting for appHcations ia dehydrogenation, oxidation, electrocatalysis, gas-phase reactions, and fuel cells (qv) (1,2,42—49). 

Phthalocyanine compounds have been synthesized with various metals (1,2,4). The most important metal phthalocyanines are derived from phthalodinitnle, phthaUc anhydride. Pc derivatives, or alkaU metal Pc salts. 

Phthalocyanines. The pyrrole ring system is also the fundamental stmctural unit of the important group of blue and blue-green pigments known as the phthalocyanines (see Phthalocyanine compounds). 

Replacement of the hydrogens ia Phthalocyanine Blue by chlorine gives a blue—green. If bromine replaces chlorine, the shades become yellower, progressively yielding pigments designated 2Y, 3Y, 6Y, and 8Y (see PHTHALOCYANINE COMPOUNDS). 

Dyes and Pigments. Several thousand metric tons of metallated or metal coordinated phthalocyanine dyes (10) are sold annually in the United States. The partially oxidized metallated phthalocyanine dyes are good conductors and are called molecular metals (see Semiconductors Phthalocyanine compounds Colorants forplastics). Azo dyes (qv) are also often metallated. The basic unit for a 2,2 -azobisphenol dye is shown as stmcture (11). Sulfonic acid groups are used to provide solubiHty, and a wide variety of other substituents influence color and stabiHty. Such complexes have also found appHcations as analytical indicators, pigments (qv), and paint additives. 

Engchpedia articles oa specific chemical types of dyes ate Azinedyes Azo dyes Cyanine dyes Dyes, anthraquinone Phthalocyanine compounds POLYTffiTHINE dyes StILBENE DYES SULFURDYES ThIAZOLE DYES TrIPHENYLT THANE AND RELATED DYES XaNTTIENE DYES. 

Consequentiy, phthalocyanines are used extensively ia printing inks and paints. The preponderance of blue and green labeling on products is testament to the popularity of phthalocyanine-based printing inks, and most blue and green cars are the product of phthalocyanine-based paints (see Phthalocyanine compounds). 

Other dyes in this group are phthalocyanine compounds which stiU have commercial importance, particularly in textile printing. 

Phthalocyanine Dyes. The phthalocyanine molecule is much too big to be used on hydrophobic fibers and therefore is only used in its sulfonated form as the basis for direct and reactive dyes (see Phthalocyanine compounds). Its forces of attraction are different from a small linear yeUow a2o dye with which it is used to form bright greens. CompatibiHty between the two is likely to be a problem in practice and to overcome this, green dyestuffs containing a phthalocyanine dye linked via a saturated chromophore blocker (—x—) have been made, eg,... 

Phthalocyanines are commonly very stable compounds. Therefore, the macrocyclic structure of these compounds is maintained during most of the chemical reactions. If reaction conditions are harsh enough to break bonds ofthe macrocyclic skeleton, usually defined or undefined97-361 products of minor interest are obtained. Usually, however, reactions on phthalocyanines can be regarded as syntheses of other phthalocyanine compounds. 

Nippon Kayaku. New Phthalocyanine Compounds Useful in Water-Based Inks are Prepared by Reacting Aminophthalocyanine Compounds with Methacrylic or Acrylic Acid. World Patent Application, 200064901 A, 27 April, 1999. 

Kaeida, O., et al. (Nippon Shokubai). Novel Phthalocyanine Compounds Production Method Thereof Near Infrared Ray Absorption Materials Containing the Same. European Patent 523,959, July 14, 1992. 

Moser, F. Thomas, A. (1963). Phthalocyanine Compounds, New York Reinhold. 

F FI Moser and A L Thomas, Phthalocyanine compounds, (New York Reinhold, 1963). 

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