Phthalocyanine
chemical compound
Phthalocyanine (H2Pc) is a large, aromatic, macrocyclic, organic compound with the formula (C8H4N2)4H2. It is of theoretical or specialized interest in chemical dyes and photoelectricity.
It is composed of four isoindole units linked by a ring of nitrogen atoms. (C8H4N2)4H2 = H2Pc has a two-dimensional geometry and a ring system consisting of 18 π-electrons. The extensive delocalization of the π-electrons affords the molecule useful properties, lending itself to applications in dyes and pigments. Metal complexes derived from Pc2−, the conjugate base of H2Pc, are valuable in catalysis, organic solar cells, and photodynamic therapy.
Properties
Phthalocyanine and derived metal complexes (MPc) tend to aggregate and, thus, have low solubility in common solvents. Benzene at 40 °C dissolves less than a milligram of H2Pc or CuPc per litre. H2Pc and CuPc dissolve easily in sulfuric acid due to the protonation of the nitrogen atoms bridging the pyrrole rings. Many phthalocyanine compounds are, thermally, very stable and do not melt but can be sublimed.
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This entry incorporates text from “Phthalocyanine” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.