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The synthesis of new Zn(II), and Si(IV) phthalocyanine (Pc) derivatives containing chalcone group was successfully achieved and the compounds were characterized by MALDI-TOF mass spectroscopy, FT-IR, ¹H NMR, ${}^{13}$C NMR, and UV-vis spectral data. The photophysical and photochemical properties of these novel Pcs were investigated in DMF. The in vitro cytotoxic effect of the compounds on mammary breast adenocarcinoma cell lines (MCF-7 and MDA-MB-231) and normal mammary breast epithelium (MCF-12A) were evaluated by using the WST assay. Based on the WST assay analysis, cytotoxicity of the Pc derivatives to mammary breast carcinoma cells was compared to normal mammary breast epithelium cells dependent on light illumination. The results of the present investigation demonstrate that all the Pc derivatives containing the chalcone group have a phototoxic effect on mammary breast cancer cells and could be promising photodynamic therapy (PDT) agents for further studies.

1,7-dithia (12-crown-4)-bridged phthalocyanine network polymers were prepared from tetracyanodibenzo-[1,7-dithia(12-crown-4)]. In addition, the synthesis of two 1,7-dithia (12-crown-4) linked peripherally octa-substituted dimeric phthalocyanines, which contain a combination of hexakis(alkylthia) side chains, is described. These extremely soluble compounds were prepared by the condensation of an iminoisoindoline derivative and a subphthalocyanine. The novel compounds are characterized by elemental analyses, UV/vis, IR, mass, ¹H NMR and ¹³C NMR spectroscopy. The electrical conductivity measurements of three of the four network polymers were unsuccessful; however chemical doping with NOBF₄ could be increased to a measurable value. The electrical conductivity of the dimeric phthalocyanines are in the semiconductor range.

By a mixed condensation of 1,3-bis(3″,4″-dicyanophenoxy)-2-ethyl-2-methylpropane with a large amount of 4,5-bis(3,3-dimethyl-1-butynyl)phthalonitrile, 1,3-bis-2″-(9″,10″,16″,17″,23″,24″-hexakis(3″,3″-dimethyl-1″-butynyl)phthalocyaninoxyl)-2-ethyl-2-methylpropane, was synthesized as a binuclear phthalocyanine having a single isomer. NMR studies at various temperatures and concentrations suggested that the interactions between the phthalocyanine macrocycles were dominated by intermolecular aggregation at lower temperatures or high concentrations whereas intramolecular aggregation was predominant at higher temperatures or lower concentrations.

The surface electrochemical response of the Co^II/Co^I redox process of tetraaminophthalocyaninatocobalt(II) (Co^IITAPc) adsorbed on a graphite electrode, was studied in the pH range of 2–13. In aqueous solution, the Co^IITAPc adsorbed graphite electrode displays very strong electrocatalytic activity toward N₂O reduction to N₂, a process which was examined by cyclic and rotating disk electrode voltammetries. The possible application of this Co^IITAPc modified electrode in N₂O analysis was explored.

The new metal-free phthalocyanine 2 and phthalocyaninatometals 3–5 (M = Ni, Co and Zn) carrying eight hydroxyethylmercapto groups on peripheral positions have been synthesized from 1,2-bis(hydroxyethylmercapto)-4,5-dicyanobenzene in the presence of a suitable anhydrous metal salt [NiCl₂, CoCl₂ or Zn(O₂CMe)₂] or hydroquinone. Zinc (II) phthalocyaninate reacted with palladium(II) salt to form complexes with a phthalocyanine (metal ratio of 1:4). The electrical conductivity of the phthalocyanines 2, 3, 5, 5a are in the semiconductor range.

Three types of amphiphilic water-soluble fluorinated zinc phthalocyanines are characterized. They have absorption bands at long wavelength, which cause greater penetration depth of a tissue. The uptake and photodynamic activity of the phthalocyanines against HeLa cells were measured, showing that the phthalocyanines exhibited higher photodynamic activities than zinc tetrasulfonated phthalocyanine.

Perylene derivative films doped with metal ion were deposited on indium tin oxide (ITO)-coated glass electrodes by electrodeposition from solutions of N, N″-4-hydroxyphenyl-3,4,9,10-perylenetetracarboxylic-diimide (hph-PTC) and CaCl₂, PbCl₂, ZnCl₂ or CoBr₂ as a supporting electrolyte in N, N-dimethylformamide (DMF). The p-n junction diodes consisting of a p-type phthalocyanine (Pc) sublimed film and an n-type hph-PTC electrodeposited film doped with metal ion exhibited Zener-type breakdown and photocurrent enhancement. The device with a p-n junction consisting of a Pc sublimed film and an hph-PTC electrodeposited film doped with Ca²⁺ showed the largest amplification of photocurrent. This result suggests that the dopant ion in hph-PTC is an important factor in the preparation of p-n junction diodes.

The reaction with sodium cyanide of the μ-oxo-bridged complex of tetra-4-tert-butyl-substituted iron phthalocyanine (form ‘690’) and that of the product of its treatment with organic bases such as Py, Im, etc. (form ‘627’) result in the formation of the same ferrous bis-cyanide complex Na₂[Pc^tFe^II(CN)₂] which can be readily oxidized to the analogous ferric complex Na[Pc^tFe^III(CN)₂]. Form ‘690’ has been oxidized to the corresponding ferric μ-oxo complex (form ‘630’). Data for all μ-oxo-bridged complexes (chemical behavior; electronic, NMR, Mössbauer, X-ray photoelectron and ESR spectra; magnetic susceptibility) are discussed, and based on them, the following structures are proposed: (HPc^tFe^II)₂O (form ‘690’), H₂[(LPc^tFe^II)₂O] (form ‘627’) and (Pc^tFe^III)₂O (form ‘630’).

The UV-vis absorption, MCD and fluorescence spectra of phthalocyaninatosilicon (SiPc) covalently linked to one or two TEMPO radicals have been studied in comparison with those of (dihydroxy)SiPc. The electronic absorption and MCD spectra show little change on substitution of TEMPO radicals, indicating that the electronic interaction between excited singlet SiPc (¹SiPc*) and doublet TEMPO (²TEMPO) is very weak or non-existent. In contrast, fluorescence quantum yields decrease markedly with increasing number of TEMPO radicals. This result is interpreted reasonably by assuming that the decay from ¹SiPc* to excited triplet SiPc (³SiPc*) partially becomes a spin-allowed transition owing to the interaction between ³SiPc* and ²TEMPO.

The synthesis of and spectroscopic data on subazaporphyrins, subphthalocyanines, subnaphthalocyanines and their related compounds reported to date are summarized, together with the results of molecular orbital (MO) calculations from our laboratory. Thus the problems and key points in the synthesis of these subazamacrocycles and their electronic absorption and magnetic circular dichroism (MCD) spectra are discussed, together with those of the monosubstituted-type low-symmetrical phthalocyanines obtained by their ring expansion reaction. The Q bands of these subazamacrocycles are orbitally doubly degenerate, and in the Soret band region, three transitions to the orbitally degenerate state are found. The MO calculations suggest that the HOMO levels destabilize considerably while the LUMO levels change slightly with increasing size of the π system. In addition, the electronic adsorption data are reproduced by the calculation only when the two pyrrole hydrogens in the monosubstituted-type phthalocyanines are assumed to be linked to the two pyrrole nitrogens along the short axis.

Serendipity has been a major player in most dye discoveries, and phthalocyanines are no exception. The true account of their discovery in 1928 is given using information provided by one of the individuals involved (Ron Greig). One of the inventors, Drescher, after making a key observation as to the nature of the insoluble blue impurity formed in the routine manufacture of phthalimide from phthalic anhydride, was killed weeks later when, on his beloved Sunbeam motorcycle, he had a head-on collision with a steamroller on his way to work. The unique properties of phthalocyanine dyes and pigments make them the colorant of choice for most blue and green colours. Thus most blue and green cars, including sports cars, are coloured by phthalocyanine pigments. In addition to these traditional uses, phthalocyanines are also finding extensive use in modern hi-tech areas. They are used for their colour as, for example, cyan dyes in ink jet printing, and in colourless applications such as infrared absorbers in security. The discovery, traditional and hitech applications of phthalocyanines are described in detail in this paper.

Rapid reactions of tetra(tert-butyl)phthalocyanine, H₂(tbpc), and its zinc complex, [Zn(tbpc)], with tellurium tetrachloride (TeCl₄) in non-aqueous solutions have been investigated. Upon mixing respective solutions containing the reactants, drastic spectral changes occurred in chloroform and toluene even at room temperature. The electronic spectra of the products indicated that the reactions involved an acid-base equilibrium where the phthalocyanines and tellurium tetrachloride acted as a Lewis base and a Lewis acid respectively. By monitoring the spectral changes based on various initial molar ratios of the reactants, the compositions of the products for each system have been determined. [Zn(tbpc)] formed a 1:1 (tbpc:TeCl₄) adduct in both chloroform and toluene, showing the same spectra close to those of the known monoprotonated phthalocyanines. On the other hand, H₂(tbpc) formed a 1:1 adduct in chloroform but a 1:3 adduct in toluene even though both products showed essentially the same spectra close to those of the known diprotonated phthalocyanines. Equilibrium constants have been calculated for the four systems. Magnetic circular dichroism (MCD) spectra of conjugated acids of phthalocyanines have been studied for the first time.

Dithallium phthalocyanine (Tl₂Pc) was synthesized by direct reaction of Tl metal with 1,2-dicyanobenzene. A thin film of the product was prepared by vacuum deposition on KCl single-crystalline substrate and its structure and epitaxy were examined by electron microscopy. The crystal structure of the thin film was the same as the orthorhombic structure reported previously. The film grew epitaxially on KCl substrate as expected from point-on-line coincidence. The UV-vis spectrum of the film was measured and compared with that of an as-synthesized powder sample. The UV-vis spectrum of the thin film of Tl₂Pc showed some differences from that of the powder in the visible region, which may result from the difference in molecular orientation. The electrical resistance of a Tl₂Pc thin film deposited on mica was about 10¹⁰Ω in our measuring set-up, which means that the film does not show high conductivity.

Polyaniline (PA) and aniline black (AB) were prepared in powder form by the chemical method of oxidative polymerization, from which free-standing thin films were obtained by solvent evaporation using N-methyl pyrrolidinone (NMP). The thin films contained 2, 4, 6 or 8 wt% AB. Electrical measurements showed that the samples containing 4% AB exhibited the highest photoconductivity of the four concentrations. Thus there appears to be a critical ratio of PA to AB for maximum photoconductivity. Annealing up to 570 K has little effect on the conductivity. Upon adding a small quantity of copper phthalocyanine (CuPc) to the PA + AB, the electrical conductivity increased considerably and the optical absorption was extended from the UV to the near IR. The electrical conductivity mechanism is a consequence of a redox process, since AB is the oxidized state of PA and, upon illumination, there is an exchange of charge carriers. The extension of the range of optical absorption upon addition of CuPc is interpreted to suggest that CuPc photosensitizes the material and enhances the carrier transport process in the redox couple. The activation energy from the temperature-dependent conductivity and the band gap from the electrolyte electroreflectance method were determined. The activation energy for 0.4% CuPc is lowest (0.52 eV) and the corresponding band gap is determined to be 3.0 eV. This organic compound could be a good candidate for inexpensive, reliable and efficient solar energy-converting devices.

In photodynamic therapy it is important to avoid undesirable side effects caused by photodynamic reactions with accumulated photosensitizers, especially in the skin. Although phthalocyanine monomers can serve as photosensitizers, aggregated phthalocyanines are inactive. In this study the aggregations of five zinc phthalocyanines (MSPc, TSPc, TX-101A, TX-105A and TX-106A) in the skin and in the tumor are compared. Every phthalocyanine was more dissociated in the tumor than in the skin. In particular, TX-101A and TX-106A remained in monomeric form in the tumor but were aggregated in the skin. The aggregation effects of phthalocyanines in organic solvents and biological materials were also investigated. These phthalocyanines were aggregated in water and ethanol and also by the addition of bovine serum albumin and ghosts of red cells. On the other hand, they were dissociated in propanol and also by the addition of low-density lipoprotein. It was found that the dissociation of these phthalocyanines depended strongly on the polarity of the solvents and on the biological microenvironment.

Several recent studies of phthalocyanines and porphyrins as materials in emerging technologies are reviewed here. Emphasis is placed on the use of these materials as components in building materials where the symmetry, optical and electrical properties of the molecule are important. Aggregates or polymers of these molecules have been known for some time to possess interesting electrical conductivities, and more recently interesting optical properties. Their optical properties as isolated species in condensed phases have also recently become interesting, and their ability to form new hybrid materials, by mixing or by thin film deposition, with other molecules with different electron affinities and ionization potentials, now appears to be extremely attractive. Device technologies in which we can anticipate these molecules appearing in the near future include organic light-emitting diodes, organic field effect transisitors, organic photovoltaics, optical limiters and optically based chemical sensors.

Phthalocyanine (Pc) derivatives in which substituents hold the Pc units in isolation from one another in the solid state are potentially useful materials. Three synthetic approaches to achieve this goal are described: the construction of a dendrimer about a Pc core; the incorporation of alkyl side chains which are forced to lie out of the plane of the macrocycle; and the synthesis of sterically crowded hexadeca-substituted derivatives. The effectiveness of each of these strategies is readily measured by comparing the visible absorption spectrum of a spin-coated film with that obtained from the non-aggregated Pc in dilute solution. These studies show that the size of the substituents is of secondary importance for their efficiency in inducing Pc isolation. Of more importance is the substituents' adopted position relative to the Pc ring.

This paper provides a review of synthesis of the phthalocyanines containing various macrocycles at the peripheral position of the benzene rings. They are expected to be suitable to change the chemical and physical properties toward the need of technologycal applications. In addition, transition and alkali metal phthalocyanine complexes especially rare-earth bis phthalocyanines, are object of intense investigations for their unique optical and electrochemical properties. The methodology of synthesis, purification and yield varies the structural designation which is restricted and depends on the starting compounds.

Tetra-2,3-pyridoporphyrazinatosilicon (SiPyD) containing bis(tri-n-hexylsiloxy) (1) or bis(n-heptylcarbonyloxy) (2) axial ligands have been prepared and characterized by NMR, IR and electronic absorption spectroscopies and by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). These SiPyDs are soluble in common organic solvents, and face-to-face-type stacking is prevented in solution and films. Accordingly, their NMR spectra could be reasonably assigned. Their electronic absorption spectra in solution appear to the blue and red compared with those of the corresponding Si phthalocyanines (SiPcs) and Si tetrapyrazinoporphyrazines (SiPyZs) respectively. These characteristics are reproduced by molecular orbital calculations in the framework of the Pariser-Parr-Pople approximation. On formation of films, the Q bands shift to the red of those in solution by ca 20 nm, suggesting that other similar tetravalent metallophthalocyanines with two long axial ligands can be used for shifting the Q band to the red. TGA and DTA experiments show that the thermal stability of the macrocycles is markedly influenced by the type of axial ligands.

The kinetics of photobleaching of zinc(II) tetra-t-butyltetrabenzoporphyrin 1, zinc(II) 13,17-diethyl-12,18-dimethyl-5-azadibenzo[b,g]porphyrin 2 and zinc(II) tetra-t-butylphthalocyanine 3 are studied. In methanol containing ca 0.1% pyridine, complex 1 undergoes photoaggregation, 2 is relatively photostable, while 3 undergoes a smooth true photobleaching process with loss of intensity across the visible region. Where appropriate, apparent first-order rate constants for the photodiminution of the α band in the spectra are reported, and the effects of solvent variation and of additives are measured. It has not been possible to provide an overall rationalization of the solvent effects, but the effects of additives support the view that the photo-oxidative processes involve singlet oxygen. Experiments with potassium superoxide do not support superoxide involvement. Preparative experiments in methanol have been carried out with 1 and 3. 1 leads to a large recovery of the starting material, indicating that the photoaggregation does not involve the formation of new covalent bonds. 3 gives rise to at least five products (besides the starting material). Two of these, isolated in low yields (<5%), are identified as a fragmentation (depolymerization) product, 4-t-butylphthalonitrile, and the expected oxidative product, 4-t-butylphthalimide. The results are discussed and conclusions drawn.