Phthalocyanine a macrocyclic compound. It consists of four isoindole-class
[(C6H4)C2N] units linked by four nitrogen atoms to form a conjugated chain,
which take play in hosting various different metal ions in its centrer. This
structure is Macrocyclic structure shows a striking feature as a colorant like
porphyrins (biopigments) in nature. Phthalocyanine derivatives derived from
the basic compound of (C6H4C2N)4N4 are used as light-fast blue or green
pigments. The hosted metals and substituted groups result in distinct colors;
phthalocyanine (blue-green), copper phthalocyanine (blue), chlorinated copper
phthalocyanine (green), and sulfonated copper phthalocyanine (green). Recently
they are involved in the study of photosensitizer chemistry or metal complex chemistry such
as transition-metal complex catalyst chemistry for uniform polymerization,
luminescence chemistry and spectrophotometric analysis, organic synthesis and
polymerization. Phthalocyanine pigments are used in enamels, linoleum, inks,
plastics, and rubber goods.