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The first detection and characterization of magnetic interaction between two 4f electronic systems in the dinuclear "inverted-sandwich-type" phthalocyanine complex with terbium ions and that of dysprosium ions are presented. Temperature dependent magnetic measurements for the diterbium complex, (μ-phthalocyaninato)bis[di(2,2,6,6-tetramethylheptane-3,5-dionato)terbium], show that the value of magnetic susceptibility times temperature, χT, sharply decreases as temperature is lowered, indicating the presence of an antiferromagnetic-type interaction between the Tb 3+ ions in the dinuclear complex. Similar temperature dependence was observed for the corresponding dinuclear dysprosium complex. These results are completely opposite to those observed for Pc triple-decker dinuclear terbium or dysprosium complexes, which are known to function as single molecule magnets. The NMR signals for the protons on the Pc ligand of the diterbium complex show up-field paramagnetic shifts due to the partially-filled 4f shells of the metal ions. This again makes sharp contrast to the triple-deckers, for which large down-field paramagnetic shifts are observed. These intriguing results seen in the NMR and magnetic susceptibility measurements are explained assuming the ligand field potential of the inverted-sandwich complexes gives strong easy-plain-type magnetic anisotropy, where Jz value of the lowest sublevel has a small value, while sandwich-type Pc3Ln2 ( Ln = Tb or Dy ) complexes have a strong easy-axis-type magnetic anisotropy.

The synthesis, and spectroscopic and magnetic properties of quadruple-decker phthalocyanines (Pcs) have been reviewed. While the presence of stacked mercury Pc oligomers was proposed as early as 1992, the isolation of a quadruple-decker Pc was first achieved in 2010. Herein, we review how the synthetic strategy for quadruple-decker Pcs has come to be conceived from the recent development of cadmium Pc oligomers, which will be followed by illustration of unique physicochemical properties originating from the structure of the quadruple-decker frameworks. In the spectroscopy section, the electronic structures of the quadruple-decker Pc are discussed based on the theoretical and experimental results. A simple molecular orbital (MO) method predicts that energy gaps among the occupied frontier MOs of the quadruple-decker Pc become smaller than those of double- or triple-decker Pcs, leading to the observation of exceptionally low-lying electronic transitions for the oxidized quadruple-decker Pcs. It has been confirmed that the corresponding lowest π–π* electronic transitions reach the infrared region for the one-electron oxidized quadruple-decker Pcs. In the magnetic property section, a clear evidence of the long-range magnetic dipole–dipole f–f interactions between two f-electronic centers of diterbium quadruple-decker Pc is provided, and its magnetic relaxation phenomena arising mainly from quantum tunneling magnetizations (QTMs) will be discussed by using the alternate current (ac) magnetic susceptibility data, and the numerically calculated Zeeman diagram of the f-electronic centers in the quadruple-decker Pc.

A trivalent manganese complex of a non-planar 1,4,8,11,15,18,22,25-octaphenylphthalocyanine derivative, 3, has been synthesized by treating metal-free 1,4,8,11,15,18,22,25-octaphenylphthalocyanine, 2, with manganese(II) chloride in refluxing DMF. X-ray crystallography has revealed that the complex adopts a highly-deformed skeletal conformation due to steric congestions between the substituted bulky phenyl groups. Although mass spectrometry results provide no indication of the presence of axial ligands, the crystal data clearly show that the manganese ion is coordinated axially by a chloride ion in addition to the four equatorial isoindole nitrogen atoms. The oxidation state of the manganese center of 3, therefore, has been assigned to 3+. Electronic absorption spectra revealed that the Q-band of 3 shows a significant bathochromic shift compared to that of the planar Mn ( III ) phthalocyanine 4 and non-planar metal-free phthalocyanine 2. The analysis of MCD and UV-vis spectra suggests that the absorption band observed at 555 nm for 3 is LMCT in origin. Electrochemical investigations indicate that the first oxidation couple is ligand-centered. Since the HOMO of 2 is destabilized due to the synergetic effects of the electron-donating phenyl groups at the non-peripheral positions and the deformed π-electronic skeleton, the resulting manganese complex 3, is anticipated to also have a ligand-centered HOMO. The results of spectroelectrochemistry confirm that the first oxidation process of 3 is indeed ligand-centered. DFT calculations indicate that the MO amplitudes of the HOMO and LUMO localize mainly on the Pc ligand and the manganese ion, respectively, also supporting the assignments of the cyclic voltammograms. By combining the manganese ion and non-planar Pc ligand, a novel, stable near-infrared (NIR)-absorbing material has been achieved in the present study.

Electrocatalytic properties of cobalt phthalocyanine (CoPc), cobalt tetra-carboxy phthalocyanine (CoTCPc) and cobalt octa-carboxy (CoOCPc), towards the detection of dicrotophos have been studied. Catalytic behavior towards the reduction of dicrotophos was found to be dependent on the pH, as well as the substitution on the phthalocyanine ring. Strong electron withdrawing groups on the phthalocyanine ring yielded best catalysis as evidenced by the enhancement of the reduction peak current, (~5 fold) compared to the bare glassy carbon electrode. The analysis gave a good detection limit of 1.25 × 10-7 M, and good linearity for the studied concentration range. A high Tafel slope value was obtained, indicating a strong interaction between dicrotophos and the cobalt phthalocyanine complex.

Mixed condensation of 1,2-dicyanofullerene (1) and 3,6-dibutyloxyphthalonitrile (2a) in the presence of nickel chloride dihydrate ( NiCl2·2H2O ) in quinoline forms an α-hexabutyloxy-substituted tribenzotetraazachlorin (TBTAC)-fullerene ( C 60) conjugate (3). UV-vis absorption and magnetic circular dichroism (MCD) properties of 3 have been obtained, and the results compared with those of the β-substituted isomer (4). Although the absorption spectra of 3 and 4 are similar in shape, a significant band shift to longer wavelength is observed for 3. According to the results of DFT calculations, the observed spectroscopic differences are ascribed to differences in the distribution of the MO amplitudes at the α- and β-positions of the TBTAC moiety.

A two dimensional colormap analysis program customized for phthalocyanines and related macrocyclic compounds has been developed in order to effectively visualize the atomic displacements from the mean plane. Eleven known phthalocyanine structures, including super- and subphthalocyanines, have been analysed as examples using the program, and the distribution of the skeletal deformations within the molecules surveyed.