Phthalocyanine Complexes of the Transition Elements

No complexes of scandium or of yttrium are known. The complexes of the lanthanides and of the actinides will be considered in Sections I and J. 

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). 

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). 

Both zirconium and hafnium tetrachlorides react with phthalonitrile at 170°C to give products which when crystallized from sulfuric acid were formulated as dihydroxyzirconium(IV) and -hafnium(IV) chloro-phthalocyanine dihydrates (284). Once again their formulation as oxy derivatives, perhaps polymeric, seems more reasonable. A sulfonated hafnium phthalocyanine has also been reported (119). 

Complexes with niobium and with tantalum are unknown. 

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