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Antibacterial photodynamic therapy (APDT) is a promising method of treatment of local infections, based on photochemical reaction of photosensitizer (PS) under irradiation with visible or near infra-red light of appropriate wavelength. A molecule of PS is activated by light energy and as a result singlet oxygen and other reactive oxygen species, which are toxic for microbes, are generated. Antibacterial action of new PS (synthetic polycationic bacteriochlorin derivatives with spectral maximum of absorbance at 760 nm) with improved features was investigated in vitro in this work. Tetra- and octacationic bacteriochlorins with lower molecular mass, as compared with ones previously proposed, turned out to be highly effective against Pseudomonas aeruginosa and Staphylococcus aureus in plankton and biofilm state: reduction of viable bacteria in biofilms reached 5log10. The dependence of the effect on PS concentration, the time of incubation with PS and light dose was ascertained. Light microscopy of biofilms after photodynamic treatment and Live/Dead staining confirmed the death of bacteria or damage of their membranes after exposure to PS and irradiation.

The use of crystalline nanoparticles of aluminium phthalocyanine (AlPc) as nanophotosensitizers for phototheranostic is a promising direction, but due to insufficient study of their properties depending on the method of production, size, ratio of solvent concentrations, the use of these compounds is not widely developed yet.The investigations of size dependence, absorption and fluorescence of AlPc nanoparticles on various particle production conditions were carried out, and optimal conditions for obtaining the most effective samples of initial solutions for their testing on cancer and immune cells were found.

Microencapsulation and targeted delivery of cytotoxic and antibacterial agents of photodynamic therapy (PDT) improve the treatment outcomes for infectious diseases and cancer. In many cases, the loss of activity, poor encapsulation efficiency, and inadequate drug dosing hamper the success of this strategy. Therefore, the development of novel and reliable microencapsulated drug formulations granting high efficacy is of paramount importance. Here we report the in vitro delivery of a water-soluble cationic PDT drug, zinc phthalocyanine choline derivative (Cholosens), by biodegradable microcapsules assembled from dextran sulfate (DS) and poly-l-arginine (PArg). A photosensitizer was loaded in pre-formed [DS/PArg]4 hollow microcapsules with or without exposure to heat. Loading efficacy and drug release were quantitatively studied depending on the capsule concentration to emphasize the interactions between the DS/PArg multilayer network and Cholosens. The loading data were used to determine the dosage for heated and intact capsules to measure their PDT activity in vitro. The capsules were tested using human cervical adenocarcinoma (HeLa) and normal human dermal fibroblast (NHDF) cell lines, and two bacterial strains, Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Our results provide compelling evidence that encapsulated forms of Cholosens are efficient as PDT drugs for both eukaryotic cells and bacteria at specified capsule-to-cell ratios.

Three water-soluble quaternized metal-free tetra-(3-pyridyl)bacteriochlorins were synthesized and characterized by UV-vis, MCD, and NMR spectroscopy as well as elemental analysis. DFT calculations are indicative of the [Formula: see text]HOMO [Formula: see text] [Formula: see text]LUMO relationship, which correlates well with the experimentally observed by MCD spectroscopy for all bacteriochlorins “reversed” sign sequence in the Vis-NIR region. TDDFT calculations also correctly predict large splitting between the [Formula: see text] and [Formula: see text] bands as well as splitting of the Soret band observed experimentally in all bacteriochlorins.

A comparative experimental study of the specific activity of drugs based on 5-aminolevulinic acid (5-ALA) and its hexyl ester (5-ALA HE) was carried out. Their ability to induce the synthesis of photoactive protoporphyrin IX in the healthy tissues of the rabbit bladder when instilling the drug solutions at various concentrations has been estimated. It was shown that 5-ALA HE results in the induction and accumulation of PPIX in the rabbit bladder epithelium at much lower concentrations than 5-ALA. Thus, a significant increase in the fluorescence intensity in comparison with the control was achieved by instillation of 5-ALA HE solution in the rabbit’ bladder at a concentration of only 0.0001% (fluorescence intensity 2.20±0.60 a.u.), and for 5-ALA – only when using a solution at a concentration of 0.3% (fluorescence intensity 2.60±1.02 a.u.).

Antibacterial photodynamic therapy is a promising method of treating local infected foci, especially surgical and burn wounds, trophic and diabetic ulcers. This work explores the photophysical and antibacterial properties of novel phthalocyanine- and synthetic-bacteriochlorin-based octacationic photosensitizers (PS). The results of the study confirm their low degree of aggregation at high concentrations, as well as high efficiency of photodynamic treatment of Gram-negative bacterial biofilms.

Cationic bacteriochlorin derivatives which molecules differing by lipophilicity and positive charge degree have been investigated in vitro as photosensitizers for photodynamic inactivation of biofilm bacteria.

We developed the original preparation Lymphotest on the basis of disulphoderivative of diaminotriphenylmet- anic dye, differing from Lymphazurin by positions if sulphogroups in benzene ring - N-[4-[[4-(diethylamino)phenyl] (2,5-disulfophenyl)methylene]-2,5-cyclohexadien-l-ylidene]-N-ethylethanaminium hydroxide, inner salt, sodium salt. The proposed compound practically does not differ by spectrum from Lymphazurin, but is much more accessible and highly lymphotropic. Lymphotest in the form of 1% aqueous solution is characterized by a high diagnostic efficiency when using direct color lymphography, low toxicity (imposed dose exceeded the anticipated maximum dose for a human in 50-1000 times) and has no locally-irritating effect when using subcutaneously.

The research is devoted to development and study of photosensitizers on a base of injectable nanoparticular formulations of phthalocyanine derivatives absorbing at long wavelength (near-infrared) range of 710–740 nm: Thiosens [liposomal form of aluminum hydroxide 1,8,15,22-tetrakis(phenylsulfanyl)phthalocyanine] and Octasens [polymeric micellar form of zinc 1,4,8,11,15,18,22,25-octachloro-2,3,9,10,16,17,23,24-octakis-(decylsulfanyl)phthalocyanine based on domestic poloxamer Emuxol-268]. Experiments have shown that the photosensitizers under study show high selectivity of accumulation and prolonged retaining at high concentration in tumor, relatively fast clearance from normal tissue and high therapeutic efficiency of photodynamic treatment on model tumors.

An unprecedented stable neutral radical nickel(II) complex of 3,5-bis(dimedonyl)azadiisoindomethene (1) was prepared by the direct reaction between 1,3-diiminoisoindoline and dimedone. A new radical complex 1 has an intense and narrow absorption at 1008 nm and can be reduced to a less stable anionic [1]− with a typical aza(dibenzo)boron dipyrromethene (aza-BODIPY) UV−vis spectrum. Complex 1, along with two other colored condensation reaction products 2 and 3, was characterized by spectroscopy and X-ray crystallography, while the paramagnetic nature of 1 was probed by EPR and SQUID methods. Complex 1 forms dimers in the solid state with short (∼3.16 A) Ni---Ni contacts. Redox data on 1 are indicative of a reversible reduction process in this complex; its magnetism suggests a S = 1/2 state with the spin density delocalized over the aza-BODIPY core. The experimental data 1 and [1]− were correlated with the density functional theory (DFT) and time-dependent DFT calculations.

Physico-chemical properties, biodistribution in animal tissues, and PDT efficacy of bacteriochlorin photosensitizers, namely cationic salts of synthetic meso-tetrakis(N-alkyl-3-pyridyl)bacteriochlorins were studied in НЕр2 cell line and in the LLC mouse model. The tested compounds showed high stability in the dark and high in vitro phototoxicity against НЕр2 cells (the half maximal inhibitory concentration LD50 in the range from 0.34 ± 0.03 to 1.5 ± 0.03 μm). Synthetic bacteriochlorins rapidly accumulate in mouse tumor tissue with tumor-to-normal tissue fluorescence contrast ratios of 2.3–3.3, possess high PDT activity against LLC cells: inhibition of tumor growth, TGI 85.8–100%, increase in life span, ILS 105.7–129.2%, response rate, RR 50–100%. The highest PDT efficacy was found for meso-tetrakis[1-(4′-bromobutyl)-3-pyridyl]bacteriochlorin tetrabromide (IC50 0.34 ± 0.03 μm in vitro, TGI and RR 100% in vivo).

Polycationic derivatives of synthetic bacteriochlorin with absorption in the near infrared range are promising for the creation of photosensitizers (PS) for antimicrobial photodynamic therapy. In the present work, the photophysical and antibacterial properties of PS based on tetracationic derivatives of synthetic bacteriochlorins: hydrophilic 3-Py4BC(EtBr)4Br4 in aqueous solution and amphiphilic 3-Py4BCHP4Br4 in the dispersion of Kolliphor ELP were studied. Analysis of absorption and fluorescence in a wide range of concentrations has demonstrated low aggregation of the PS over the entire range. A high efficiency of photodynamic inactivation of Gram-positive Staphylococcus aureus and Gramnegative Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii bacteria was observed.

The possibility of using iron oxide(III) nanoparticles covered with photoactive derivative of zinc phthalocyanine for diagnostics and treatment of malignant tumors was studied experimentally.

An efficient synthetic route for the preparation of benzene or 1,2-naphthalene fused and phenyl substituted metal-free tetraazachlorins with yields up to 40% was developed using In ( III ) as a removable template. New substituted tribenzotetraazachlorins derivatives with tert-butyl and phenylsulfanyl groups in β and α position of fused benzene rings, correspondingly, were synthesized by novel approach and their spectral properties were investigated.

Reaction of tetrachlorophthalonitrile with some C -nucleophiles was studied. Only one chlorine atom was substituted regioselectively in the position 4 of benzene ring with diethyl malonate and malononitrile; no reaction occurred in case of bulkier diethyl ethylmalonate and ethylmalononitrile. In case of dimedone the domino substitution of two chlorine atoms, first with C -nucleophile followed by enolate O -nucleophile led to the mixture of two dibenzofuran derivatives. Remaining chlorine aroms n malonate and dibenzofuran derivatives were substituted with thiols, but in malononitrile derivative high acidity of methine proton led to the formation of stable carbanion under basic conditions that prevents further substitution. Hexadecasubstituted zinc phthalocyanines were synthesized from some new phthalonitriles.

Interaction of isomeric 4-nitro- or 3-nitrophthalonitrile with triethyl phosphonoacetate, diethyl cyanomethylphosphonate or tetraethyl methylenediphosphonate in basic conditions resulted in regioselective C -nucleophilic oxidative substitution of hydrogen ortho-located to nitro group, new phthalonitriles with diethoxyphosphorylmethyl or bis(diethoxyphosphoryl)methyl group were isolated in modest yields. In the same conditions one chlorine atom of tetrachlorophthalonitrile was regioselectively substituted with triethyl phosphonoacetate. In basic conditions, both parent phthalonitriles and corresponding zinc phthalocyanines with ortho-located nitro and diethoxyphosphoryl substituted methyl groups are involved in reversible acid-base interaction accompanied with large bathochromic shift of their long wavelength absorption maxima in visible or NIR region, correspondingly. Formation of tetraazachlorin- and tetraaza(iso)bacteriochlorin-like anions is proposed for explanation of this unprecedent bathochromic shift for phthalocyanines.

Aminopropyl groups on the surface of aminopropylated silica gel were lengthened by grafting of additional propyleneimine units and applied to immobilize singlet oxygen sensitizers of cationic phthalocyanine series. The absorption and fluorescence spectra, generation of singlet oxygen and photobactericidal activity were studied for aqueous suspensions of these new heterogeneous systems. The effect of spacer length upon absorption and emission spectra as well as on efficacy of singlet oxygen generation by tethered phthalocyanines was not observed. However, the photobactericidal function of the supported phthalocyanines was markedly increased along with length of spacer.

Синтезированы обладающие чрезвычайно высокой основностью безметальный 3,6-октагексоксифталоцианин и его комплексы с цинком и магнием. При взаимодействии с трифторуксусной кислотой в хлористом метилене получены все четыре протонированные формы безметального производного и его комплекса с цинком, определены константы протонирования. В случае магниевого комплекса из-за деметаллирования в кислых растворах получены лишь первая и вторая протонированные формы. Исследованы спектральные и фотохимические свойства протонированных форм синтезированных соединений. Квантовые выходы фотодеструкции безметального окта-3,6-гексоксифталоцианина и его комплексов с Mg и Zn в диметилформамиде составили 1·10-3, 2.6·10-3 и 4·10-3, квантовые выходы генерации синглетного кислорода – 0.02, 0.35 и 0.53, соответственно. Выявлено резкое повышение фотостабильности и снижение эффективности генерации синглетного кислорода на каждой ступени протонирования.

A new method of preparation and the properties (solubility, aggregation, spectralluminescent properties, singlet oxygen and photobleaching quantum yields) of non-metal 2,3,9,10,16,17,23,24-octacarboxyphthalocyanine are reported. The influence of ionization state on photophysicochemical properties of this dye is also presented.

Expanded phthalocyanine (Pc) congeners with two Mo or W central metal ions and four isoindole ring moieties have been synthesized using normal Pc formation conditions in the presence of urea. The products have been characterized by electrochemistry; mass spectrometry (MS); IR, electron paramagnetic resonance (EPR), NMR, electronic absorption, and magnetic circular dichroism (MCD) spectroscopies; and X-ray analysis. The X-ray structures have rectangular C(2v) symmetry and provide evidence that the central Mo atoms are linked by a single bond and coordinated by two isoindole nitrogen atoms and two nitrogen atoms from the amine moieties. The electronic absorption bands extend into the 1200-1500 nm region. This can be explained using Gouterman's four-orbital theory. The experimental NMR data and theoretical calculations provide evidence for a heteroaromatic 22-π-electron conjugation system for the ring-expanded Pc system, which satisfies Hückel's (4n + 2)π aromaticity.

A new method of synthesis of phthalocyanines with phosphonate moieties by reaction of chloromethyl substituted phthalocyanines with phosphorus trichloride in the presence of aluminum chloride followed by hydrolysis of the intermediately formed phosphonic acid chlorides under mild conditions is developed. A number of phosphonomethyl substituted phthalocyanines with different central metal atoms (aluminum, silicon, titanium, copper, zinc and gallium) and/ or with the presence of unreacted chloromethyl groups were obtained. Significant dependence of monomer – aggregate equilibrium and, as consequence, of photochemical and photophysical properties of the synthesized complexes on pH value was found. Quantum yields of singlet oxygen generation and photodegradation of complexes were determined. The photodestruction of the synthesized compounds, except of rather photostable copper phthalocyanine, proceeds with participation of self-sensitized singlet oxygen and is significantly accelerated by the presence of chloromethyl groups in the macrocycle.

Three approaches to the synthesis of reduced derivatives of tetraazaporphine such as tetraazachlorin, tetraazabacteriochlorin, and tetraazaisobacteriochlorin are reviewed. The first synthesis of alkyl-substituted tetraazachlorins was achieved by the catalytic hydrogenation of magnesium complexes of tetraazaporphines. Two other synthesis approaches for reduced tetraazaporphines based on the mixed condensation of the precursors with different hydrogenation levels and β–β addition reactions have been developed in the last decade. The use of tetramethylsuccinonitrile as the saturated component in the mixed condensation with derivatives of aromatic and heteroaromatic dicarboxylic acids enable the synthesis of oxidation-resistant benzo-; 1,2- and 2,3-naphtho-; pyrazino-; 2,3- and 3,4-pyridino-fused tetraazachlorins, tetraazabacteriochlorins, and tetraazaisobacteriochlorins. Fullerene conjugates of reduced tetraazaporphine derivatives were obtained using 1,2-dicyanofullerene as the source of the hydrogenated sites. Tetraazaporphine can act as dienophile in Diels-Alder reaction with dienes of the anthracene and cyclopentadiene series and also as dipolarophile in 1,3-dipolar cycloadditions with azomethine ylides and nitrones. In addition, the effect of the reduction of peripheral double bonds in tetraazaporphine macrocycle alone, and in combination with annelation of benzene or heterocyclic rings on the absorption spectra is discussed.

A series of zinc and aluminum phthalocyanines containing 3–8 pyridiniomethyl or cholinyl substituents on average were synthesized. As the number of cation substituents increased, in aqueous solutions, the aggregation ability of phthalocyanines decreased, while the quantum yields of fluorescence and singlet oxygen generation increased. The photodynamic inactivation of coliform bacteria sensitized by zinc and aluminum phthalocyanine polycations with an increase in the substitution degree became more effective.

Mixed condensation of tetramethylsuccinonitrile and either 2,3-dicyano-5,6-diethylpyrazine, 2,3-dicyanopyridine, or 3,4-pyridinedicarboximide in the presence of nickel chloride forms novel pyrazine-, 2,3-pyridine-, or 3,4-pyridine-ring-fused tetraazachlorin (TAC), tetraazabacteriochlorin (TABC), and tetraazaisobacteriochlorin (TAiBC) derivatives. All possible structural isomers were separated using repeated thin-layer chromatography and have been investigated by absorption and magnetic circular dichroism spectroscopy. Similarly to previously reported TAC analogues, the TAC and TABC derivatives show large splitting of the Q band, while a single, intense absorption band is observed for the TAiBC derivatives. Although the absorption spectra are practically identical in shape for the separated structural isomers of TACs and TABCs, the Q-band maxima of the TAiBCs depend significantly on their structures. The observed spectroscopic properties were interpreted on the basis of electrochemical data and the results of (time-dependent) DFT calculations.

Nucleophilic replacement of chlorine atoms in tetrachlorophthalonitrile by the action of primary and secondary amines was studied. The reactions of tetrachlorophthalonitrile with amines at a ratio of 1: 10 gave with high yields and regioselectivity the corresponding 4,5-diamino-3,6-dichlorophthalonitriles from cyclic secondary amines and 4-amino-3,5,6-trichlorophthalonitriles from primary amines and acyclic secondary amines. 4-Amino-3,5,6-trichlorophthalonitriles were used to synthesize cobalt and zinc phthalocyanine complexes. It was shown that replacement of chlorine atoms in the pyrrolic β-positions of hexadecachlorophthalocyanines by amino groups is not accompanied by red shift of the long-wave absorption band in the electronic spectra.

Chlorine-containing products of incomplete nucleophilic substitution in tetrachlorophthalonitrile were subjected to further reaction with nucleophiles. The nature of the nucleophiles and the order of their introduction into stepwise nucleophilic substitution in tetrachlorophthalonitrile were shown to be of principal importance for selective synthesis on this basis of phthalonitrile derivatives with various substituents.

Summary In 1992–2006 at P.A. Hertsen Moscow Oncology Research Institute photodynamic therapy (PDT) was performed in 48 esophageal cancer patients (total 48 lesions). For PDT we used Russian photosensitizers (Photogem, Photosens, Radachlorin, Alasens), Russian diode lasers (Crystall) and endoscopic equipment. As a result of PDT complete regression was in 77% of esophageal cancer lesions, partial regression was in 23%. The follow-up period was 3–11 years. Median of survival was in 4.59 years of esophageal cancer patient.

The [4+2]-cycloaddition reaction of unsubstituted tetraazaporphine as the dienophile with a series of dienes of the cyclopentadiene series gave novel norbornene-condensed tetraazachlorins, tetraazabacteriochlorins, and tetraazaisobacteriochlorins. It was shown that, depending on the type of the diene, the reagent ratio, reaction time, and temperature mono-or bis-adducts are formed. The compounds obtained were characterized by the elemental analyses, electronic absorption spectra, 1H NMR spectra, and mass spectra.

Several Zn (II) and Al (III) phthalocyanines bearing eight or sixteen positive charges on substituents of different structure have been prepared. Synthesized polycationic phthalocyanines have been studied in aqueous and alcoholic media by UV-vis spectroscopy and tested for their efficacy in singlet oxygen photosensitization. It has been found that a minor structural modification at the periphery of the photosensitizer allows control over its key features such as singlet oxygen generation due to specific intermolecular interactions in solution. The efficacy of polycationic phthalocyanines to sensitize tryptophan photobleaching in aqueous media and inactivation of bacteria in sewage water is also structure-dependent. Among the complexes studied, two dyes - zinc octakis(pyridiniomethyl)- and octakis[ N -(2-hydroxyethyl)- N , N -dimethylammoniomethyl]substituted phthalocyanines - are the best sensitizers and have high potential for photodynamic applications.

A series of conjugates of sulfo- and carboxy-substituted phthalocyanines with rhodamines were prepared, and their electronic absorption and luminescence spectra were studied. An intramolecular transfer of the excitation energy from the rhodamine moiety (donor) to the phthalocyanine moiety (acceptor) was revealed.

Nucleophilic substitution of chlorine atoms in tetrachlorophthalonitrile by benzene- and alkanethiols in the presence of a base was studied at different reactant ratios. The substitution is characterized by complete regioselectivity: the chlorine atom in position 4 of tetrachlorophthalonitrile is replaced first; next follows replacement of the 5-chlorine atom. The reactions of tetrachlorophthalonitrile with nucleophiles at ratios of 1:2 and 1:4 lead to the formation of the corresponding 3,6-dichloro-4,5-bis[phenyl(alkyl)sulfanyl]- and tetrakis[phenyl(alkyl)sulfanyl]phthalonitriles. The latter were converted into metal complexes of [phenyl-(alkyl)sulfanyl]-substituted phthalocyanines which absorb in the red and near-IR regions of the electronic spectra.

Nucleophilic substitution of chlorine in tetrachlorophthalonitrile by the reaction with aryloxy anions is studied. Depending on the reactant ratio, the products of substitution of one, two, and/or three chlorine atoms are formed. Their tetramerization gives aryloxychloro-substituted phthalocyanines having the absorption band in the near-IR range.

New oxidation-resistant hexaphenyl-substituted tetramethyltetraazachlorin, its nickel complex, and tetraphenyl-substituted octamethyltetraazabacteriochlorin and octamethyltetraazaisobacteriochlorin nickel complexes were synthesized for the first time by mixed condensation of diphenylm aleonitrile with tetramethylsuccinonitrile in the presence of lithium dimethylaminoethoxide or nickel chloride. The products were characterized by electronic absorption, 1H NMR, and mass spectra. Mixed condensation of diphenylsuccinonitrile with phthalonitrile in the presence of nickel chloride was found to give nickel complexes of phenylsubstituted benzo-fused tetraazaporphyrins rather than their hydrogenated derivatives.

Cobalt, zinc, hydroxoaluminum, and iron complexes of N,N′,N″,N‴-tetrakis(β-diethylaminoethyl) phthalocyanine-2,3 : 9,10 : 16,17 : 23,24-tetrakis(dicarboxamide) were synthesized and were converted into the corresponding water-soluble quaternary salts by treatment with methyl iodide, methyl p-toluenesulfonate, diethyl and dimethyl sulfates, and trimethyl phosphate. The electronic absorption spectra of the quaternary salts indicated their considerable aggregation in aqueous solution; the degree of aggregation decreases in going to solutions in ethanol and disappears in DMSO.

The photodynamic activity and pharmacokinetics of a new liposomal form (LF) of the sensitizer Photosense based on aluminum sulfophthalocyanine salts have been studied in comparison to those of the standard form (SF) representing a 0.2% aqueous solution of the parent substance. The effective therapeutic doze of the LF of Photosense in mice bearing Ehrlich's tumor was 1 mg/kg, which is four times as small as the effective dose of the SF. The selectivity of accumulation in the tumor tissue 24 h after administration for the LF of Photosense was 1.5 times higher than for the SF. The drug accumulation in skin (determined by the fluorescence intensity) on the 7th days of experiment for the LF of Photosense was 1.6 times lower than for the SF. The pharmacokinetics of the LF of Photosense in mice without tumors significantly differs from the behavior of the SF.

The importance of singlet oxygen mechanism in photooxidation of phthalocyanine chromophore has been studied for promising singlet oxygen sensitizers: metal-free tetra-tert-butyl phthalocyanine and its Zn , Mg or Al complexes. It has been found that involvement of singlet oxygen in phthalocyanine photodegradation is dependent on the presence and character of the central metal atom, being the most prominent for the metal-free compound and almost negligible for the Al complex. The interaction of dioxygen with metal centers results in a sharp increase of phthalocyanine photooxidation rate.

Methods of synthesis of covalent conjugates of metal complexes of octa-4,5-carboxy- and tetra-4-carboxyphthalocyanine, as well as of octa-6,7-carboxy-2,3-naphthalocyanine with α-amino acids, glycine and sarcosine, were developed and certain properties of the products were studied. The prepared conjugates are soluble in organic solvents and water.

The dependence of the quantum yield of photogeneration of singlet oxygen with aluminum sulfophthalocyanines on the degree of their sulfonation was studied. Experiments showed that Fotosens preparation containing, on the average, about three sulfo groups in the macroring in aqueous buffer solution (pH 7.4) exists in the monomeric form and sensitizes singlet oxygen with a quantum yield ϕΔ 0.42±0.06. Aluminum tetra-4-sulfophthalocyanine forms dimers, and correspondingly ϕΔ is lower: 0.22±0.03. Sulfonated aluminum phthalocyanine containing, on the average, about two sulfo groups in the macroring is aggregated to a significant extent. Addition of Triton X-100 detergent results in partial deaggregation of the dye, and ϕΔ increases from ∼0.01 to 0.15±0.02. In the series including previously unknown aluminum phthalocyanines containing residues of phosphonic acids or their esters, and also aluminum and zinc octacarboxyphthalocyanines, the influence of the dye structure on the quantum yield of generation of singlet oxygen suggests participation of axial hydroxy groups in associate formation. These associates are not manifested spectroscopically and generate singlet oxygen inefficiently. The quantum yields ϕΔ for the monomers and associates are 0.3 and 0.1, respectively.

The first β-oxatetraazachlorin derivatives have been synthesized starting from phthalonitrile derivatives and 5,5-dimethyl-1,3-oxazolidine-2,4-dione instead of the previously employed tetramethylsuccinonitrile. Absorption and magnetic circular dichroism (MCD) spectral properties are similar to those obtained for the corresponding tetramethyl-substituted TAC derivatives, confirming the presence of the low-symmetry aromatic structures.

Reaction of iron tetra-4-tert-butylphthalocyanine (Pc t Fe) with oxygen in noncoordinating solvents at Pc t Fe concentrations within (0.63-10.71) × 10-2 M was studied. The uptake of oxygen (moles per mole of iron phthalocyanine taken into reaction) depends on the concentration of the complex, varying in the examined concentration range from 1/5 to 1/2.7, and thus can significantly differ from the value implied by the stoichiometry of the PctFe μ-oxo dimer. This fact is due to consumption of the reactants in side processes, including oxidative degradation of the macroring. Indeed, the μ-oxo dimer is the major but not the only product of reaction of PctFe with oxygen: Up to 20% of the initial complex undergoes oxidative degradation. These data, in combination with the spectral and chemical properties of the PctFe μ-oxo dimer, suggest that this compound is an Fe(2+) derivative.