Kuninobu Kasuga

Preparation and some properties of perfluoroalkoxy-substituted phthalocyanine complexes of iron(III), nickel(II) and zinc(II)

Abstract Tetrakis(2′, 2′, 3′, 3′, 4′, 4′, 5′, 5′-octafluoropentoxy)phthalocyanine complexes of iron(III), nickel(II) and zinc(II) were prepared and characterized. The complexes were soluble in polar solvents such as ethanol and methanol but insoluble in less polar solvents such as benzene and toluene. The electron-withdrawing fluorine atoms in the substituents strongly affected the electrochemical and spectroscopic properties of the complexes.

Cycloaddition of carbon dioxide to propylene oxide catalysed by tetra-t-butylphthalocyaninatoaluminium(III) chloride

Abstract Cyclic propylene carbonate was obtained from propylene oxide in the presence of 1-methylimidazole with atmospheric carbon dioxide at room temperature using tetra- t -butylphthalocyaninatoaluminium(III) chloride as catalyst. The reaction proceeded via insertion of propylene oxide and carbon dioxide between the aluminium(III) ion and the axial ligand. Coordination of the base such as 1-methylimidazole to the aluminium(III) weakens the bonding between the aluminium(III) and the axial ligand, promoting the insertion of carbon dioxide.

Spectral and electrochemical properties of vanadyl hexadecafluorophthalocyanine

A vanadyl complex with perfluorinate phthalocyanine, VOPcF16, was prepared. The monomer-dimer solvent dependence was confirmed based on the solvent effect for the Q-band position-that is, VOPcF16 exists as a monomer in a nonpolar solvent such as benzene, but dimerizes in a polar solvent such as acetone. Electron spin resonance data also supported the solvent dependence found. In addition, the substituent effect of fluorine atoms on the redox properties was investigated by measuring the cyclic voltammograms in dichloromethane. On the reduction side, three redox couples were observed, the first two of which were assigned as being due to the reduction of the phthalocyanine ring (to LUMO), whose potentials are 0.4–0.5 V higher than those of the tetra-t-butyl and octabutoxy derivatives, VOPc(t-Bu)4 and VOPc(O-n-Bu)8.

Photocatalytic decomposition of trichlorophenol by zinc(II) phthalocyanine derivatives in aerated organic solvents

Abstract Trichlorophenol was photodecomposed by irradiation with visible light using zinc(II) phthalocyanine derivatives as a photosensitizer in aerated organic solvents. An oxidative quenching pathway via a generation of hyperoxide was proposed.

Thermotropic liquid crystalline polymers containing five-membered heterocyclic groups. VIII. Synthesis, and liquid crystalline and photoluminescent properties of semi-rigid polyesters based on a distyrylbenzene analogue of 1,3,4-thiadiazole

New semi-rigid polyesters composed of the distyrylbenzene analogue of 1,3,4-thiadiazole, 2,5-bis(2-phenylethenyl)-1,3,4-thiadiazole and aliphatic (dodeca-, deca- and octamethylene) chains were prepared by high temperature solution polycondensation; their liquid crystalline (LC) and photoluminescent properties were investigated. Differential scanning calorimetry, polarizing microscopy and powder X-ray diffraction show that the polyesters having both dodeca- and decamethylene chains form a thermotropic smectic C phase and a lyotropic LC phase in trifluoroacetic acid, but the polyester containing octamethylene chains only exhibits a thermotropic smectic C phase. Solution and solid state absorption and fluorescent spectra indicate that all the polyesters in this work display absorption maxima based on the 2,5-bis(2-phenylethenyl)-1,3,4-thiadiazole moiety, emitting blue light in HFIP solutions and bluish-green light in solids; the Stokes shifts are 80.1-80.7 nm in solution and 74.2-87.2 nm in the solid state.

Oxygen-oxygenation of cyclohexene catalyzed by manganese(III), iron(III) and cobalt(II) complexes of tetra-tert-butylphthalocyanine in the presence of iso-butyraldehyde

Abstract The title reaction was catalyzed by the manganese(III), iron(III), and cobalt(II) complexes of tetra-tert-butylphthalocyanine, but not by the ligand itself and its zinc(II) complex. When the cobalt(II) complex was used as the catalyst, an induction period was observed.

Bathochromic shift of the Q-bands of octakis(p-t-butylbenzyloxy)phthalocyanines with magnesium(II), nickel(II) and copper(II) in a solvent mixture of chloroform and acetic acid

1,4,8,11,15,18,22,25-octakis(p-t-butylbenzyloxy)phthalocyanine complexes of magnesium(II), nickel(II) and copper(II) were prepared by refluxing the propanol solution of 3,6-di(p-t-butylbenzyloxy)phthalonitrile in the presence of magnesium turnings. The complexes showed intense Q-bands between 740 and 750 nm in chloroform. The magnesium(II) complex showed an additional weak band at 807 nm in chloroform, while the nickel(II) and copper(II) did not. The Q-band of the magnesium(II) species was red-shifted with increase of acetic acid in the solvent mixture of chloroform and acetic acid; 745, (765, 807) and (810, 868 nm) in chloroform, 0.1% (v/v) acetic acid and 60% (v/v) acetic acid, respectively. The magnesium(II) complex has bands at 900 and 999 nm in trifluoroacetic acid. In the solvent mixture of 1% (v/v) acetic acid, the red-shift of the Q-band was larger for the magnesium(II) derivative, a little for the nickel(II) and scarcely for the copper(II), respectively. The shift was explained by protonation of the external nitrogen atoms of the phthalocyanine ring.

THE FIXATION OF CARBON DIOXIDE WITH 1,2-EPOXYPROPANE CATALYZED BY ALKALI-METAL HALIDE IN THE PRESENCE OF A CROWN ETHER

Abstract Cyclic carbonate was obtained from a chloroform solution of 1,2-epoxypropane under carbon dioxide atmosphere using alkali-metal halide as catalyst in the presence of a crown ether.

Catalytic oxygenation of olefin with dioxygen and tetra-t-butylphthalocyanine complexes in the presence of sodium borohydride

Abstract Catalytic oxygenation of styrene with dioxygen was performed by tetra-t-butylphthalocyanine complexes of manganese(III), iron(III), and cobalt(II) in the presence of sodium borohydride using ethanol as a solvent. The yield of 1-phenylethanol increased with the passage of time in the case of the manganese(III) and iron(III) complexes, but an induction period appeared in the case of the cobalt(II) complex. The initial reaction rate was 2.8 × 10−3 or 3.4 × 10−2 mmol min−1 for the reaction catalyzed by the manganese(III) or cobalt(II) complex respectively. No oxygenation product was formed in anaerobic ethanol with any of the complexes, but ethylbenzene was formed exclusively in the presence of the cobalt(II) complex. A radical scavenger, 2,2,6,6-tetramethylpiperidine-1-oxyl, inhibited the reaction considerably with the manganese(III) or iron(III) complex, but inhibited the reaction slightly with the cobalt(II) complex. The amount of oxygenation product from α-methylstyrene was larger than that from styrene in the case of the manganese(III) and iron(III) complexes, but the amount of oxygenation product from α-methylstyrene was almost the same as that from styrene in the case of the cobalt(II) complex. A radical mechanism is proposed for the oxygenation reaction of olefin catalyzed by the complexes. In the case of the cobalt(II) complex, a σ-bound intermediate may also contribute to the reaction.

The Radical Formation of Diphthalocyanine Complexes of Lanthanum(III), Neodymium(IIl) and Yttrium(III) with p-Benzoquinone

Abstract Three species of neodymium(III) phthalocyanine: PcNdPcH (λ max = 345 and 636 nm), radical PcNdPc (324, 470 and 676 nm) and PcNdCH 3 COO (336 and 675 nm) were obtained from a crude neodymium(III) phthalocyanine mixture by column chromatography on silica gel. The diphthalocyanine complexes of lanthanum (III), neodymium(III) and yttrium(III) were oxidized to the radical with p -benzoquinone and the reaction rate was increased with the decrease of an ionic radius, e.g. the rate was increased with the decrease of the distance of two macrocycles in the complex.