Phthalocyanine derivatives

Synthesis. Usually a substituted phthalodinitrile or a substituted phthalic acid is used as starting material. A mixture of an unsubstituted and substituted starting material in approximate ratios, respectively, of 1 3, 2 2, or 3 1 can also be used. When reactivities of the two starting materials are approximately equal, Pc derivatives whose degree of substitution closely corresponds to the ratio of the starting materials are obtained. More often, however, a mixture of products results. 

With the exception of tetrachlorophthalic acid, substituted phthalic acids, phthalimides, or phthalonitriles are industrially not readily accessible in pure form. 

Substitution. Copper phthalocyanine is preferred as starting material. Very little is known about the position of substitution. With the exception of hexadeca-chloro CuPc, all commercial Pc substitution products, as well as the tetrasubsti-tuted derivatives synthesized from monosubstituted phthalic acids, are mixtures of isomers. Despite the 16 hydrogen atoms that can be substituted, only two different monosubstituted Pc s are possible. The number of disubstituted isomers is higher. Mono- to heptasubstituted Pc derivatives have not yet been isolated in isomerically pure form. In addition, only a limited number of isomers are accessible in pure form by synthesis. Only symmetrically substituted phthalic acids, phthalimides, or phthalodinitriles (3,6-di-, 4,5-di-, or 3,4,5,6-tetrasubstituted derivatives) yield pure isomers of octa- or hexadecasubstituted phthalocyanine derivatives. All other substituted phthalic acids give mixtures of isomers. 

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Depending upon the metallic compound used, different metallic phthalocyanine derivatives are obtained, e.g. when copper chloride is used copper phthalocyanine (Monastral Fast Blue B) is obtained. 

Fig. 6. Dyes for WORM media phthalocyanine derivatives. The basic stmcture (12) of naphthalocyanine derivatives. Y = Si, Ge, Sn, Al, Ga, In, or a transition metal = ORj, OSiR R R, polymer. and represent substituents on the tings of the naphthalene system.

Incorporation of less than a stoichiometric amount of alkyl sulfonamides of copper phthalocyanines into copper phthalocyanine improves the pigment s properties in rotogravure inks (67). Monomeric and polymeric phthalocyanine derivatives with basic substituents adsorb strongly to the pigment surface and promote the adsorption of binder molecules (68—72). 

LB films of 1,4,8,11,15,18-hexaoctyl-22,25-bis-(carboxypropyl)-phthalocyanine (2), an asymmetrically substituted phthalocyanine, were stable monolayers formed at the water—air interface that could be transferred onto hydrophilic siUca substrates (32—34). When a monolayer film of the phthalocyanine derivative was heated, there was a remarkable change in the optical spectmm. This, by comparison to the spectmm of the bulk material, indicated a phase transition from the low temperature herringbone packing, to a high temperature hexagonal packing. 

Little is known about the O2 adducts of cofacial corrole/porphyrin, cofacial biscor-role, or cofacial phthalocyanine derivatives (Fig. 18.13). 

The new phthalocyanine derivatives in Scheme 10 have recently been reported to be capable of recording high-quality signals at higher speeds.221... 

It should be noted that the patent literature describes a vast number of phthalocyanine derivatives for use as CD-R dyes along the lines already described, with almost every conceivable combination of central metal, axial groups on the central metal, and peripheral substituents on the ligand however, the difference between real and proposed molecules is not obvious, and experimental information and optical performance data is sketchy at best. 

Fuxi, G. Tao, L. Optical properties and recording characteristics of phthalocyanine-derivative LB films. Proc. SPIE Vol. 2053, 95-105. Optical Storage Third International Symposium, Fuxi, G. Ed. 

Several zinc(II) and aluminum(III) phthalocyanine derivatives substituted with carboxylic acid and sulfonic acid groups were anchored to nanocrystalline Ti02 films and tested for their photovoltaic behavior.72,73 Interestingly, zinc(II)-2,9,16,23-tetracarboxyphthalocyanine (55) exhibited 45% monochromatic current conversion efficiency at 700 nm. It is shown that electron injection to Ti02 occurs from the excited singlet state of the phthalocyanine derivatives. The... 

Table 3 Photophysical and photobiological properties of silicon(IV) phthalocyanine derivatives with...

It should be noted that the basic reactions used to prepare phthalocyanine derivatives today are fundamentally those developed by Linstead and coworkers in the 1930s [52-54]. Due to the large number of substituted phthalocyanines described in the literature, space limitations mean that a detailed review of synthetic aspects cannot be provided here. The following discussion is concerned with the synthesis of lanthanide phthalocyanines via (i) template tetramerization of phthalonitrile with lanthanide salts, (ii) direct metalation of the metal-free ligands by the salts or (iii) metal exchange of a labile metal ion or ions for a lanthanide. 

In addition to the discussed cyclotetramerizations, direct metallation of the metal-free ligands or metal exchange of a labile metal ion or ions for one held more robustly, the desired complexes may be prepared by the direct substitution, exchange or modification of substituents on preformed phthalocyanine derivatives. However, a review of works carried out on these types of transformations lies out of the scope of this chapter. 

Copper phthalocyanine derivatives are well established as turquoise blue direct and reactive dyes for cellulosic fibres. Chlorosulphonation at the 3-position, followed by hydrolysis, yields sulphonated direct dyes such as Cl Direct Blue 86 (5.32 X = H) and Blue 87 (5.32 X = S03Na). Solubility and dyeing properties can be varied by introducing four chlorosulphonyl groups, some of which are hydrolysed and some converted to sulphonamide by reaction with ammonia or alkylamines. This approach is also the main route to reactive dyes of the copper phthalocyanine type. The reactive system Z is linked to a 3-sulphonyl site... 

Mdssbauer spectra of NaY-encapsulated FePc(t-Bu)4/NaY and external FePc(t-Bu)4+NaY at 78 K are shown in Fig 4. The Mfissbauer paraaeters after curvefitting analysis suggested that the Fe precursor in NaY reacted with 1,2-dicyanobenzene to be converted into iron phthalocyanine derivatives without any other residual species of iron. The appreciable difference was observed for I.S. and Q.S. values between the internal and external sanples of FePc(t-Bu)4, suggesting that the electron density at the central Fe of FePc(t-Bu)4 inside... 

The pseudorotaxane self-assembles through hydrogen bonding, and the binding constant, calculated using steady-state fluorescence, is 1.4 x 10. The zinc phthalocyanine derivative exhibited an excited-state lifetime of approximately 3.1 ns. The fast decay of the excited state of 1 ZnPc upon complexation with the fullerene... 

Metal-semiconductor-metal or metal-insulator-semiconductor (MIS) devices have been constructed using polymerized phthalocyanine derivatives with PF5 as the dopant (phosphorane structure)34. 

Since complexes of 2,2 -bipyridyl and 1,10-phenanthroline with chromium in oxidation states I and 0 can be obtained by reduction (Scheme 64) of the chromium(n) complexes, these oxidation states will be considered together. Oxidation, as shown in Schemes 65 and 68 of Section 35.4.2.5, gives chromium(III) complexes, which are often best prepared in this way. Earlier work has been extensively reviewed, and few complexes of 2,2 6, 2"-terpyridyl are known.32 A chromium(I) phthalocyanine derivative is mentioned in Section 35.4.9.3. 

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