Nickel phthalocyanine preparation

Besides the above mentioned method of Tomoda [phthalonitrile, nickel(II) acetate, 1,8-diaza-bicyclo[5.4.0]undec-7-ene, pen tan-1-ol], nickel phthalocyanine (PcNi) is prepared from phthalonitrile and nickel(II) acetate in 2-(dimethylamino)ethanol117 or with nickel(II) chloride in quinoline.1 30-1 59-277-278 The formation of PcNi also takes place without solvent137 or with nickel(II) acetate in ethylene glycol.127... 

In 1929, Linsted obtained samples of this complex from ICI chemists (Scottish Dyes Ltd was now owned by ICI). ICI had developed two routes leading to the phthalocyanine iron complex. One method started from phthalic anhydride, iron, and ammonia, while the second pathway proceeded from phthalimide, iron sulfide, and ammonia. In 1933/34, elucidation of the phthalocyanine structure was credited to Linstead. The corresponding copper and nickel phthalocyanines had been prepared in the meantime. ICI introduced the first Copper Phthalocyanine Blue to the market as early as 1935, and the Ludwigshafen subsidiary of the IG Farben-industrie followed suit with a corresponding product. 

Y-junction carbon nanotubes were prepared by the pyrolysis of nickelocene-thiophene employing the experimental set-up described earlier [1]. Pyrolysis of nickel phthalocyanine-thiophene mixtures was carried out to obtain N-doped carbon nanotubes with Y-junctions. 

Nickel phthalocyanine is conveniently prepared by heating etched nickel foil in o-cyanobenzamide at 270°C (10). An alternative preparation involves phthahc anhydride, urea, nickel chloride hexahydrate, and ammonium molybdate in trichlorobenzene at 200°C (81). It is stable to concentrated sulfuric acid, sublimes readily, and shows no tendency to form six-coordinate derivatives (10, 213, 325). 

The monovalent and zerovalent phthalocyanines may be prepared as their lithium salts as previously described. The former has one unpaired electron and the latter is diamagnetic (340). No other nickel phthalocyanines are known. 

Khene et al. [7] used Ordinary Pyrolytic Graphite (OPG) coated with both as-prepared and activated NiPc, NiPc(OH)4 and polyNi(OH)Pc(OH)4, respectively. At the NiPc(OH)4/OPG electrode oligomers fouled the electrode surface, while with polyNi(OH)Pc(OH)4/OPG higher currents for the oxidation of 4-CP were observed, although with a shift to more positive potentials. As said above, the authors concluded that the activation led to a catalytic O-Ni-O bridged structure of the nickel phthalocyanine films. 

In an interesting study, phthalocyanine complexes containing four anthraquinone nuclei (5.34) were synthesised and evaluated as potential vat dyes and pigments [18]. Anthraquinone-1,2-dicarbonitrile or the corresponding dicarboxylic anhydride was reacted with a transition-metal salt, namely vanadium, chromium, iron, cobalt, nickel, copper, tin, platinum or lead (Scheme 5.6). Substituted analogues were also prepared from amino, chloro or nitro derivatives of anthraquinone-l,2-dicarboxylic anhydride. 

The first structural report on a phthalocyanine complex concerned [Ni(pc)J (Table 110 I).2878 In the crystal lattice of this compound the square planar macrocycles are arrayed in slipped stacks such that the distance between the molecular planes along the perpendicular direction is 388 pm. [Ni(pc)] may be prepared by a variety of methods 2873,2871 2880 a convenient one is heating a foil of elemental nickel in o-cyanobenzamide at 270 °C (Scheme 60).2881 [Ni(pc)] is insoluble in the most common organic solvents, but soluble in concentrated sulfuric acid from which it is reprecipitated unchanged upon dilution. This complex is thermally very stable and may be sublimed in vacuo. The reduction of [Ni(pc)] can be accomplished by chemical or electrochemical methods and results in ligand-based reduced anions [Ni(pc)]" ( = 1, 2). Analogously, the electrochemical oxidation results in the oxidized ligand. 3... 

Although strictly not a dendritic system, Agar et al.[75] have reported the preparation of copper(n) phthalocyaninate substituted with eight 12-membered tetraaza macrocycles as well as its nickel(n), copper(n), cobalt(n), and zinc(n) complexes. Thus, the use of the l,4,7-tritosyl-l,4,7,10-tetraazacyclododecane offers a novel approach to the 1 — 3 branching pattern and a locus for metal ion encapsulation. 

In order to increase the solubility of porphyrin and phthalocyanine complexes, several structural modifications have been made, a, jS, y, 6-Tetra-(4-pyridyl)-porphin complexes of copper(II), nickel(II), and zinc(II) have been synthesized (35) and their ultraviolet spectra determined in chloroform and in acid solution. By utilizing sulfonic acid groups to increase solubility, complexes of 4,4, 4",4" -tetrasulfophthalocyanine complexes of many metals were prepared (94j 95). This chelating agent was found to have a ligand field strength comparable to cyanide (94y 95). 

Sugimori T, Horike SI, Handa M, Kasuga K (1998) Preparation and some properties of perfluoroalkoxy-substituted phthalocyanine complexes of iron(lll), nickel(ll) and zincfll). Inorg Chim Acta 278 253-255... 

The phthalocyanines constitute an important class of synthetic pigments and dyes. The parent compound is Pigment Blue 16 (phthalocyanine). One method of preparation involves the fusion of phthalonitrile with cyclohexylamine in an inert solvent. The two central hydrogen atoms can be replaced by metals such as copper, nickel, iron, and cobalt. 

The polymer support route is based on the fixation of a phthalonitrile (A) on a polymer, while a different phthalonitrile (B) is added forming a l 3-product, which can be isolated by removing it from the polymer. Unsymmetrically octalkoxy-substituted nickel palladium and platinum phthalocyanines have been prepared recently starting from differently disubstituted phthalonitriles [91]. 

---