Narrow Results

A series of 4-(polyfluoroalkoxy)phthalonitriles have been prepared in high yield by nucleophilic substitution of the nitro group in 4-nitrophthalonitrile on polyfluoroalkoxy groups at room temperature. These dinitriles have been cyclotetramerized in the presence of cobalt or copper salts into the corresponding phthalocyanine complexes. The spectral properties and coordination chemistry of some of them have been studied.

The synthetic pathways to obtain 4-triphenylmethylphthalodinitrile, complexes of tetra (4-triphenylmethyl)phthalocyanine with copper, nickel and cobalt, and di(4-triphenylmethyl)triazolehemiporphyrazine are described.

Pd(II), Co(II), Cu(II) and Zn(II) phthalocyanines with a tricarbethoxyethyl substituent on each benzo group were prepared from 4-(1,1,2-tricarbethoxyethyl)-phthalonitrile and the corresponding divalent metal salt at 170°C. Transesterification occurred when the reaction was carried out in pentanol. Treatment of the palladium complex with sodium ethoxide at room temperature and further acidification resulted with tetra(1,2-dicarboxyethyl)phthalocyaninatopal-ladium. Its UV-vis spectrum in aqueous solution indicated dimeric and monomeric species at pH ≈ 12, but at pH ≈ 6 only the dimeric form were present.

A new route to the synthesis of 4-chloro-5-alkyl-phthalonitrile derivatives was shown by the displacement reaction of 4,5-dichloro-phthalonitrile and diethylmalonate, a CH-acidic precursor, in the presence of K₂CO₃. Cyclotetramerization of 1-chloro-3,4-dicyano-6-(1,1-dicarbethoxy-methyl)benzene and the metal salt without any solvent gave the corresponding metallophthalocyanines (M = Co, CuorPd). Transesterification occurred when the reaction was carried out in hexanol in the presence of DBU to obtain the metal-free derivative. Treatment of 1-chloro-3,4-dicyano-6-(1,1-dicarbethoxy-methyl)benzene with sodium ethoxide at ambient temperature and further acidification resulted in 2,9,16,23-tetra(carboxymethyl)-3,10,17,24-tetrachloro-phthalocyaninatopalladium(II) with partial decarboxylation. Its electronic spectrum in aqueous solution indicated no appreciable change over a pH range from 7 to 12.

Compound 1 (2,4,6-tris(2-oxaphthalonitrile)-s-triazine) has been prepared by the reaction of 4-nitrophthalonitrile and cyanuric acid in dry DMF as the solvent in the presence of K₂CO₃ as the base. An interesting s-triazine, containing three oxa metal phthalocyanines (M = Zn, CoorCu) has been synthesized from compound 1, 4,5-bis(hexylthio)phthalonitrile and the corresponding anhydrous metal salts (Zn (OAc)₂, CoCl₂ or CuCl) by the method of statistically mixed condensation. The new compounds and phthalocyanines were obtained in sufficient purity after successive washings with different solvents and were characterized by elemental analysis, UV-vis, IR, NMR and EPR spectroscopy.

The mixture of phthalonitrile and metal salt in 1,1,3,3-N,N,N',N'-tetramethylguanidinium trifluoroacetate as an ionic liquid without using any other reagents or solvents converted to the metallophthalocyanine under conventional heating conditions in relatively good yields at 130°C after less than 1 h. The ionic liquid can be recovered conveniently and reused efficiently.

We have synthesized a series of tetrakis(arylvinylene)phthalocyanines from the corresponding phthalonitriles. Substitution of the para-fluorine in the pentafluorphenyl ring with an alkoxy group from the solvent occurs during the synthesis. This substitution can be suppressed by the addition of zinc chloride or tin chloride to the reaction mixture. According to ¹H and ¹⁹F NMR data, the cis- or trans-conformations of the starting materials are retained during condensation; thus the phthalocyanines formed are in all-cis or all-trans form. Cis-trans photoisomerization occurs easily for phthalonitriles, while phthalocyanines retain their conformations under UV beam.

The synthesis of new phthalonitrile derivatives by photoinduced reaction is described. Novel unsymmetrically substituted Zn(II) phthalocyanine bearing an aryl alcohol group (ArZnPc) was synthesized by the ring expansion reaction of boron(III) subphthalocyanine chloride with an appropriated phthalonitrile. The spectroscopic and photodynamic properties of these ArZnPc were studied.

Perfluoro phthalonitrile substituted separately with perfluoroalkyl (EWG) and NH₂, NHMe, and NMe₂ (EDG) groups generate a series of aromatic C-H bonds-free nitriles that can now lose electrons, whose HOMO–LUMO gap is narrowed by EDG beyond the level induced by EWG, and whose dipole moments double. Molecular parameters vary linearly with Hammett’s free-energy constants, their electronic underpinning being uncovered by DFT calculations. The phthalonitriles’ assembling in solid-state structures is determined by forces that transition from van der Waals, in the case of EWG, to H-bonding and/or $\pi$-stacking interactions in the case of EDG, as revealed by their single-crystal X-ray structures.