Nickel phthalocyanine

Fig. 3. TEM images of CNTs obtained by CVD of nickel phthalocyanine on a quartz substrate at 800°C the bottom of the tube (right) and tip of the tube (left).

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... 

The products are called 1,4-octasubstituted or 1,4,8,11,15,18,22,25-octasubstituted phthalocyanines. In this case only one structural isomer is possible. 3,6-Diheptylphthalonitrile when refluxed in pentan-1 -ol in the presence of nickel(II) acetate and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) for 48 hours yields the nickel phthalocyanine 16. 

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. 

Fig. 16 (a) Variation of current density with reciprocal temperature for ohmic and SCL currents in nickel phthalocyanine (NiPc) crystal thickness... 

Zhang and Rusling [66] employed a stable, conductive, bicontinuous microemulsion of surfactant/oil/water as a medium for catalytic dechlorination of PCBs at about 1 mA cm-2 on Pb cathodes. The major products were biphenyl and its reduced alkylbenzene derivatives, which are much less toxic than PCBs. Zinc phthalocyanine provided better catalysis than nickel phthalocyanine tetrasulfonate. The current efficiency was about 20% for 4,4 -DCB and about 40% for the most heavily chlorinated PCB mixture. A nearly complete dechlorination of 100 mg of Aroclor 1260 with 60% Cl was achieved in 18 hr. Electrochemical dehalogenation was thus shown to be feasible in water-based surfactant media, providing a lower-cost, safer alternative to toxic organic solvents. 

Agboola BO, Ozoemena KI, Nyokong T (2006) Electrochemical properties of benzylmer-capto and dodecylmercapto tetra substituted nickel phthalocyanine complexes electrocatalytic oxidation of nitrite. Electrochim Acta 51(28) 6470-6478... 

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. 

X lO M, respectively. These observations apply to ferrous, cobaltous, and manganous phthalocyanines, and it is noteworthy that the cupric, magnesimn, and nickel phthalocyanines had no significant catalytic activity. It appears, therefore, that oxidation of the central metal ion by one-electron transfer plays an important role in initiating autoxidation. 

Some papers have appeared that deal with the use of electrodes whose surfaces are modified with materials suitable for the catalytic reduction of halogenated organic compounds. Kerr and coworkers [408] employed a platinum electrode coated with poly-/7-nitrostyrene for the catalytic reduction of l,2-dibromo-l,2-diphenylethane. Catalytic reduction of 1,2-dibromo-l,2-diphenylethane, 1,2-dibromophenylethane, and 1,2-dibromopropane has been achieved with an electrode coated with covalently immobilized cobalt(II) or copper(II) tetraphenylporphyrin [409]. Carbon electrodes modified with /nc50-tetra(/7-aminophenyl)porphyrinatoiron(III) can be used for the catalytic reduction of benzyl bromide, triphenylmethyl bromide, and hexachloroethane when the surface-bound porphyrin is in the Fe(T) state [410]. Metal phthalocyanine-containing films on pyrolytic graphite have been utilized for the catalytic reduction of P anj -1,2-dibromocyclohexane and trichloroacetic acid [411], and copper and nickel phthalocyanines adsorbed onto carbon promote the catalytic reduction of 1,2-dibromobutane, n-<7/ 5-l,2-dibromocyclohexane, and trichloroacetic acid in bicontinuous microemulsions [412]. When carbon electrodes coated with anodically polymerized films of nickel(Il) salen are cathodically polarized to generate nickel(I) sites, it is possible to carry out the catalytic reduction of iodoethane and 2-iodopropane [29] and the reductive intramolecular cyclizations of 1,3-dibromopropane and of 1,4-dibromo- and 1,4-diiodobutane [413]. A volume edited by Murray [414] contains a valuable set of review chapters by experts in the field of chemically modified electrodes. 

An X-ray study of the structure of the phthalocyanines. Part I. The metal-free, nickel, copper, and platinum compounds, J. M. Robertson, J. Chem. Soc., 1935,615, An X-ray study of the phthalocyanines. Part II. Quantitative structure determination of the metal-free compound, J. M. Robertson, J. Chem. Soc., 1936, 1195 An X-ray study of the phthalocyanines. Part III. Quantitative structure determination of nickel phthalocyanine, J. M. Robertson and I. Woodward, J. Chem. Soc., 1937, 219 An X-ray study of the phthalocyanines. Part IV. Direct quantitative analysis of the platinum compound, J. M. Robertson and I. Woodward, J. Chem. Soc., 1940, 36. 

Benzyl phenyl sulphide was oxidized to benzyl phenyl sulphone quantitatively in 6h with iron phthalocyanine as catalyst. Experiments were similarly carried out with other metal phthalocyanines using phenyl and benzyl phenyl sulphides. Experiments using copper phthalocyanine, nickel phthalocyanine and no catalyst, were carried out for 24 h and the products analysed by HPLC. These results are presented in Table-1. In these experiments... 

Results in Table-1 show that with iron phthalocyanine (Fe(II)Pc), manganese phthalocyanine (Mn(II)Pc) and cobalt tetrasulphonatophthalocyanine (Co(II)TSPc) as catalyst both phenyl and benzyl phenyl sulphides could be quantitatively oxidized to corresponding sulphones in 3-6 h. However, oxidation of benzyl phenyl sulphide to the corresponding sulphone with vanadyl phthalocyanine took 18h. In case of copper phthalocyanine (Cu(II)Pc) and nickel phthalocyanine (Ni(II)Pc), no sulphone formation was detected even after 24h, and the products analysis by HPLC showed the formation of 61% and 4.2% benzyl phenyl sulphoxide, respectively. The results for the oxidation of benzyl phenyl sulphide with Ni(II)Pc as catalyst and without any catalyst (entry 9, 10 Table-1) show that Ni(II)Pc rather gave negative effect in these oxidations. 

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. 

Certain metal derivatives, particularly the ferrous and chloroferric complexes, catalyze the decomposition of hydrogen peroxide. They are themselves destroyed in the process (58, 127, 871). Paquot and his coworkers have extensively investigated the catalytic properties of the phthalocyanines (71, 270-277). Nickel phthalocyanine is a useful catalyst for the autoxidation of a-carbon atoms of ethylenic molecules. Thus nickel phthalocyanine (0.4%) catalyzes the aerial oxidation of cyclo-... 

The X-ray absorption edge spectra of iron, cobalt, and nickel phthalo-.cyanines have been recorded. When a compound absorbs X-rays, a Is electron is considered to make a transition to some unoccupied orbital of the K-electron excited atom (i.e., an atom having a hole in the K shell). Nickel phthalocyanine showed absorption at 7 and 18.5 eV 248), iron phthalocyanine at 18 eV, and cobalt at 25 eV 117). The second maximum may be due to a second order plasma interaction (i.e., transition from a... 

Fujiki M, Tabei H and Kurihara T 1988 Self-assembling features of soluble nickel phthalocyanines J. Phys. Chem. 92 1281-5... 

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