Phthalocyanine

• 29H, 31H - tetrabenzo [b, g, l, q] [ 5,10,15,20 ] tetraazaporphin
• 5,28:14,19 - Diimino 7,12:26,21 - dinitrilotetrabenzo [c, h, m, r] [ 1,6,11,16 ] tetraazacycloeicosin
• C. I. 74100
• C. I. Pigment Blue 16

Black to dark blue / purple crystals

Fixed

> 300 ° C

550 ° C ( sublimation)

• Insoluble in water
• Soluble in sulfuric acid

Attention

Template: Infobox chemical / molecular formula search available

Phthalocyanine (of phthalic acid, and gr cyanos, κυανός, blue) is the namesake of the phthalocyanines, a class of macrocyclic compounds having an alternating nitrogen-carbon ring structure. Structurally, they are similar to the related classes of organic dyes such as the porphyrin and the cyanines. Phthalocyanines are characterized by high chemical and thermal stability. Phthalocyanine - abbreviated Pch2 - is resistant to concentrated sulfuric acid and can be sublimed at 500 ° C. in a vacuum. Four in the phthalocyanine benzopyrrole units via nitrogen ( aza- ) bridges are connected. The systematic name is Tetrabenzotetraazaporphyrin.

History

The first occurrence of an unknown blue -product has been described in 1907. It is now known that this acted to a metal - free phthalocyanine. The actual discovery of the phthalocyanine dye as also happened by chance, as in 1928 in the Scottish work of Scottish Dyes Ltd.. (ICI ) should be made ​​in Grangemouth phthalimide from phthalic anhydride and ammonia in enamelled iron boilers. At one point where the enamel had chipped up to iron, a dark blue substance was formed. In subsequent experiments it was found that the blue color could be obtained not only with iron, but also by reaction of phthalonitrile with other metals such as copper or nickel or their salts.

A year earlier had Henri de Bach and E. This is already reported from the meadow in the journal Helvetica Chimica Acta on the synthesis and the brilliancy of color of copper phthalocyanine, but without realizing its economic potential as a pigment. The Linstead of 1933 porphinartige postulated structure of the phthalocyanine was used by Robertson in 1935 by X-ray structural analysis. It was clear that the phthalocyanines biologically relevant metal complexes such as the red blood pigment heme or chlorophyll of plants are similar.

The commercial production of copper was recorded in 1934 by ICI. Bayer followed in 1936 and brought the substance as Heliogenblau B on the market. The inorganic pigments used hitherto ultramarine and Prussian blue were largely obsolete in the coming years. Later, the range has been extended by the Metallphthalocyaninpigmente exchange of copper to cobalt or nickel but also by chlorination ( phthalocyanine green ) and sulfonation ( high water solubility ) of the base body.

Production and representation

The phthalocyanine macrocycle is built up of four identical (corner ) blocks. As a synthesis strategy is therefore to provide raw materials that meet these corners. These are usually derivatives of phthalic acid, such as phthalonitrile, phthalic anhydride, phthalimide or Diiminoisoindol.

Conventional techniques

First, the salts of different transition metals may be reacted with phthalonitrile, and sodium methoxide in a suitable solvent. On the other hand, the reaction of elemental transition metals with 1,3- Diiminoisoindol can take place in solution. In both cases, the corresponding metal phthalocyanine obtained at 80-140 ° C, or in the case of PCH2 absence of metals or salts thereof. Also possible is the implementation of various transition metal salts with urea and phthalic anhydride in an inert, high-boiling solvent using ammonium as a catalyst and tetramethyl urea as a promoter. The reaction solution thus requires a temperature of 120-250 ° C. The use of other phthalocyanine precursors is possible with this, also industrially used, process. In the absence of metals or their salts in this case Pch2 is also formed.

Microwaves

For the synthesis of metal phthalocyanines by the irradiation with microwaves is expected from metal-free phthalocyanines, which are reacted with the zinc, magnesium, cobalt and copper salts of acetic acid or hydrochloric acid. As the product is in this case the metal tetra- tert- butylphthalocyanine receive appropriate. Important for the reaction, a reaction mixture is free of any organic solvents. Metal phthalocyanine sandwich complexes ( MPC 2 ) can only be produced in this way. Another possible application is in the production of CuPc by the reaction of copper ( I) chloride with urea and phthalic anhydride in the presence of a catalyst. The yield can be increased by using higher - energy microwaves.

Ultrasound

Reactions ultrasound can be conducted at room temperature. The time required varies from one minute to eight hours. On the one hand can be obtained by the reaction of phthalonitrile with copper ( I) chloride in a suitable solvent copper phthalocyanine. Alternatively, the reaction of copper ( I) chloride with Dichlorsilikon phthalocyanine monomers and a Natriumchalkogen enables the construction of poly ( phthalocyanato ) siloxanes [Si ( Pc) O ] n

Electrosynthesis

The method of electrophotographic synthesis also provides a means to present at room temperature phthalocyanines. Among other phthalonitrile of the anode with the corresponding metal salt in alcoholic solution at the cathode is reacted. As Cu -, Ni -, Co - and Mg - phthalocyanine complex may be represented by using methanol. The use of ethanol allows the synthesis of Pb phthalocyanine.

Irradiation (UV / VIS)

The irradiation of the reaction mixture consisting of phthalonitrile in an alcohol in the presence of sodium methoxide at room temperature provides PCH2.

Irradiation (laser )

For the production of copper phthalocyanine ( CuPc), a copper target is bombarded with a laser in this method. The ejected copper atoms can be incorporated into a thin film of 1,3 - Diiminoisoindol which CuPc is obtained.

Other methods

In addition to the above-described shortly methods exist among other possibilities synthesis at relatively low temperatures (<100 ° C ) to carry out. This overlap thematically with the electric syntheses. Furthermore, it is possible to produce, inter alia, be by irradiation or electrochemical methods phthalocyanine radicals which are stable under atmospheric oxygen. The last method is, for the sake of completeness, the representation of phthalocyanine complexes using radioactive elements or radioactive isotopes of stable elements are called.

Use

Phthalocyanines are used as dye ( Dye) on optical media (CD -R) and as pigments for plastics, coatings and in the paper industry. In addition, they may serve as photoconductors in laser printers, or as an electrode material in fuel cells. In the chemical research phthalocyanine is used as easy to produce a model substance for the biologically important porphyrins. Furthermore find phthalocyanine derivatives application in photodynamic therapy. In this phthalocyanines are enriched in the tumor tissue, and ( 600-800 nm in wavelength ) excited by light, which reactive singlet oxygen is liberated. Due to the associated secondary reactions occur within a few hours by necrosis and apoptosis of cell death, which after 4-6 weeks ideally leads to total resolution of the tumor.

Phthalocyanine derivatives

• Aluminum phthalocyanine, CAS: 14154-42-8
• Nickel phthalocyanine, CAS: 14055-02-8
• Cobalt phthalocyanine, CAS: 3317-67-7
• Iron phthalocyanine, CAS: 132-16-1
• Zinc phthalocyanine, CAS: 14320-04-08
• Copper, CAS: 147-14-8
• Polychlorkupferphthalocyanin, CAS: 1328-53-6
• Hexadecachlorphthalocyanin, CAS: 28888-81-5
• Hexadecabromphthalocyanin, CAS: 28746-04-5
• Manganese phthalocyanine, CAS: 14325-24-7