Phthalocyanine

Blue to purple powder

Phthalocyanine is a common macrocylic blue-green dye able to form coordination complexes with many elements on the periodic table.

phthalocyanine: A synthetic compoundhaving molecules with fourisoindole rings linked by –N= bridges.The structure is similar to that of theporphyrins. It can form complexeswith central metal ions. Copperphthalocyanines are used as dyes.

Phthalocyanine is a group of benzoporphyrins which have strong pigmenting power, forming a family of dyes.
The basic structure of the molecule comprises four isoindole groups (C₆H₄,)C₂N, joined by four nitrogen atoms. Four commercially important modifications are: (a) metal free phthalocyanine (C₆H₄C₂N)₄, having a bluegreen color,(b copper phthalocyanine in which a copper atom is held by secondary valences of the isoindole nitrogen atoms, (c) chlorinated copper phthalocyanine, green, in which 15 to 16 hydrogen atoms are replaced by chlorine, and (d) sulphonated copper phthalocyanine, water-soluble and green, in which two hydrogens are replaced by sulphonic acid groups. It is used in decorative enamels and automotive finishes; chlorophyll and haems have basic phthalocyanine structures in their molecules.

Purify phthalocyanine by sublimation (two to three times) in an argon flow at 300-400Pa; and similarly for the Cu(II), Ni(II), Pb(II), VO(II) and Zn(II) phthalocyanine complexes. [Beilstein 26 III/IV 4255.]