Titanium complexes phthalocyanine

Mbambisa G, Tau P, Antunes E, Nyokong T (2007) Synthesis and electrochemical properties of purple manganese(III) and red titanium(IV) phthalocyanine complexes octa-substituted at non-peripheral positions with pentyl thio groups. Polyhedron 26(18) 5355-5364... 

This is a rather surprising result, and it seems more likely that the complex should be formulated as oxytitanium(IV) phthalocyanine monohydrate. An infrared study would confirm this since oxy titanium (IV) phthalocyanine shows, in addition to the spectrum characteristic of a phthalocyanine, a strong band at 978 cm"1 (341) (965 cm-1) (213), assigned to the Ti=0 stretching vibration. The complex may therefore be regarded as five-coordinate and presumably square pyramidal. The complex is slowly decolorized in chlorobenzene solution in air, phthalimide being the final product (213) (see also Section VI,C). 

There are other metal complexes, such as tin, aluminum, magnesium, iron, cobalt, titanium, and vanadium complexes, which are similarly useful in stabilizing a particular phthalocyanine modification. Moreover, carboxy, carbonamido, sulfo, or phosphono-copper phthalocyanine may be admixed during fine dispersion of the pigment. 

Very few complexes have been examined. It is known that (Pc)TiCl can be converted t (Pc)TiO.152 Dichloro(phthalocyaninato)titanium(lV) can be synthesized via equation (27). Th reaction is a convenient one, inasmuch as the titanium(III) furnishes the electrons necessary t convert phthalonitrile to the phthalocyanine anion.153... 

TV-phenylbenzohydroxamic acid, 506, phthalocyanines, 865 polypyrazolylborates, 248 porphyrins, 823 pseudohalides, 228 Titanium(III) complexes octaethylporphyrin reaction with dioxygen, 325 Titanium(IV) complexes 1,3-diketones, 376 triazines... 

Abstract This chapter discusses the electronic absorption spectra and electrochemistry of phthalocyanine complexes which are redshifted to 730nm and beyond. These are mainly manganese phthalocyanine derivatives and phthalocya-nines containing sulfur substituents. The chapter concentrates mainly on the work done during the last 10 years. There are 96 references quoted and three detailed tables on the electronic absorption spectra, redox potentials, and analytes that are electrocatalyzed using manganese and titanium phthalocyanine complexes. 

Recent reviews of the phthalocyanines by Lever (57) and by Moser and Thomas 66) are available. Complexes of phthalocyanine with all of the first row transition elements, excepting scandium, have been prepared. However, titanium and vanadium phthalocyanines are known only as the oxy- or chloro-compounds and are not then strictly square planar. That phthalocyanine has considerable ability to promote the square planar configuration is further demonstrated by the existence of the chromium (III) and manganese(II) complexes (57). 

Chlorotitanium(III) phthalocyanine is formed by the reaction of titanium trichloride with dilithium phthalocyanine in boiling quinoline in the absence of air. This d1 complex has a magnetic moment of 1.79 B.M. (see Section VI,D) 341). It is stable to air oxidation in the solid state but is oxidized in solution. The oxidation product is oxytitanium(IV) phthalocyanine (titanyl phthalocyanine). This latter diamagnetic complex may also be prepared by the reaction of titanium tetrachloride dipyridinate and phthalonitrile at 270°C followed by sublimation at 400°C/10 6 mm 213). Titanium tetrachloride reacts with phthalonitrile to yield, after recrystallization from sulfuric acid, dihydroxytitanium(IV) phthalocyanine 820). 

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