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The pentafluorosulfanyl (SF5) group is more electronegative, lipophilic and sterically bulky relative to the well‐explored trifluoromethyl (CF3) group. As such, the SF5 group could offer access to pharmaceuticals, agrochemicals and optoelectronic materials with novel properties. Here, the first synthesis of phthalocyanines (Pcs), a class of compounds used as dyes and with potential as photodynamic therapeutics, with a SF5 group directly attached on their peripheral positions is disclosed. The key for this work is the preparation of a series of SF5‐containing phthalonitriles, which was beautifully regio‐controlled by a stepwise cyanation via ortho‐lithiation/iodination from commercially available pentafluorosulfanyl arenes. The macrocyclization of the SF5‐containing phthalonitriles to SF5‐substituted Pcs required harsh conditions with the exception of the synthesis of β‐SF5‐substituted Pc. The regiospecificity of the newly developed SF5‐substituted Pcs observed by UV/Vis spectra and fluorescence quantum yields depend on the peripheral positon of the SF5 group.

A redox potential controlled intermolecular [2 + 2] cross-cycloaddition has been developed in the presence of a thioxanthylium photoredox catalyst. Electron-rich styrenes such as β-bromostyrene (E p/2 = +1.61 V vs SCE) were selectively oxidized by a thioxanthylium photoredox catalyst (E 1/2 (C*/C•–) = +1.76 V vs SCE) to styryl radical cations and reacted with styrene (E p/2 = +1.97 V vs SCE) to furnish polysubstituted cyclobutanes in high yields. The present reaction can be successfully applied to intermolecular [2 + 2] cross-cycloaddition of β-halogenostyrenes, which cannot be effectively achieved by the hitherto reported representative organophotoredox catalysts.

The effect of temperature is discussed on the magnetic-alignment process of micron-sized particles dispersed in a fluid medium, based on the experimental data compiled on various non-ferromagnetic materials having different concentrations of paramagnetic impurity ion. The fieldintensity required to achieve alignment decreased with temperature following the relation calculated from the Langevin theory, when the diamagnetic particles were free of paramagnetic ions. The rotational Brownian motion was considered to randomize the direction of the microcrystals in the theory. The above-mentioned temperature dependence was expected to occur for most of the diamagnetic oxides, since the oxides were expected to posses a finite amount of diamagnetic anisotropy according to a model proposed recently to explain the origin of anisotropy. The decease of temperature caused additional reduction on the field-intensity to achieve alignment, when finite amount of paramagnetic ion was contained in the particle. This was because the paramagnetic anisotropy increased which the reduction of temperature. The doping of paramagnetic ion on non-ferromagnetic materials in the course of processing a material expected to reduce the field intensity to achieve magnetic alignment at room temperature. The above findings, concerned with the reduction of field intensity to achieve magnetic alignment, may increase the possibility of practical applications of the phenomena of magnetic alignment. (Received June 20, 2003; Accepted November 14, 2003) Keywords: diamagnetic anisotropy, magnetic alignment at low magnetic field, temperature dependence of magnetic alignment, magnetic alignment of micron-sized particle, magneto-rotation, Curie temperature dependence of paramagnetic anisotropy, doping of paramagnetic ion, ceramic material, kaolinite, graphite