Luminescence of In(III)Cl-etioporphyrin-I.

The luminescent and photophysical properties of the etioporphyrin-I complex with indium(III) chloride, InCl-EtioP-I were experimentally studied at room and liquid nitrogen temperatures in pure and mixed toluene solutions. At 77 K, in a 1:2 mixture of toluene with diethyl ether, the quantum yield of phosphorescence reaches 10.2%, while the duration of phosphorescence is 17 ms. At these conditions, the ratio of phosphorescence-to-fluorescence integral intensities is equal to 26.1, which is the highest for complexes of this type. At 298 K, the quantum yield of the singlet oxygen generation is maximal in pure toluene (81%). Quantum-chemical calculations of absorption and fluorescence spectra at temperatures of 77 K and 298 K qualitatively coincide with the experimental data. The InCl-EtioP-I compound will further be used as a photoresponsive material in thin-film optoelectronic devices.

Aggregation of 2,3-dihydroxy-etiochlorin I. An amphiphilic model compound for photodynamic therapy and green heme d.

The crystal structure of 2,3-dihydroxy-etiochlorin I has been determined to obtain information on its aggregation behavior. Cis-dihydroxychlorins serve as model compounds for green heme d and show promising photonecrotic activity in photodynamic therapy. The compound shows strong aggregation in the solid state facilitated by intramolecular hydrogen bonding between one hydroxy group and pyrrole nitrogens of neighboring molecules. This novel type of aggregation leads to chain-type aggregates in the crystal. The title compound 4 crystallized in the monoclinic space group Ia (Z = 4) with unit cell dimensions a = 9.902(4) A, b = 26.430(9) A, c = 10.823(5), beta = 104.47(3) A, V = 2743(2) A3. The structure was refined to an R-value of 0.097 on the basis of 1150 reflections with F > 4.0 sigma (F) (130 K).

New sensitizers for photodynamic therapy: controlled synthesis of purpurins and their effect on normal tissue.

Purpurins are a class of porphyrin derivative that have been shown to have good in vivo cytotoxicity to N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) induced rat bladder tumors (AY-27) implanted into Fisher 344 rats. The synthesis of purpurins from etioporphyrin I and coproporphyrin I proceeds in high yield and with a high degree of regioselectivity. Product formation can be rationalized in terms of relief of steric strain about the periphery of the purpurin macrocycle. The effect of therapeutic light doses using the rat footpad model suggests that, at therapeutic sensitizer doses, normal tissue damage is within acceptable limits, particularly for metalated purpurins.

Origins of etioporphyrins in sediments: evidence from stable carbon isotopes.

In samples of the Julia Creek and Condor oil shales (Australia, Albian, and early Tertiary, respectively) etioporphyrin III is significantly depleted in 13C (4%) relative to porphyrins derived from chlorophylls. This isotopic difference suggests a large contribution from some independent source. The haem group found in cytochromes derived from microbial sources is the most likely candidate.

[Fine structure luminescence of etio-, copro- and mesoporphyrin following selective laser excitation]. / Tonkostrukturnaia liuminestsentsiia étio-, kopro- i mezoporfirina pri selektivnom lazernom vozbuzhdenii.

Fluorescence line spectra of etio- and coproporphyrin isomers and mesoporphyrin IX, as well as their ionic forms have been obtained and investigated using a tunable dye laser excitation (T = 4.2 K). Normal vibrational frequencies in the ground electronic state of both the neutral molecules and their ions have been determined. By comparing the line spectra of different porphyrins and their isomers the distinctions have been revealed which may be used for the identification of these compounds in solutions. Changes have been discovered in the coproporphyrin ion spectra in different solvents.

Electron transport across glycerol monooleate bilayer lipid membranes facilitated by magnesium etiochlorin.

The transport of electrons across biological membranes is believed to play an important role in many biophenomena. Although there have been many examples of systems which may be transporting electrons across Mueller-Rudin bilayer lipid membranes (blm), none has been well characterized. The system we describe here comprises a glycerol monooleate blm containing a magnesium etiochlorin (Mg-C) separating two aqueous phases each containing ferricyanide, ferrocyanide, KCl, and a platinum electrode. The E0s for the Mg-C+/Mg-C and ferri-/ferrocyanide couples are 0.22 and 0.24 V vs. SCE. Thus the MG-C+/Mb-C system is easily poised by the ferri-/ferrocyanide system. When the potentials of the ferri-/ferrocyanide couples are different on each side of the blm we show that the open-circuit membrane potential nearly equals the difference between the redox potentials. This is unequivocal evidence that electrons are being transferred across the blm from one aqueous phase to the other. On the basis of these experiments we deduce that electron transport is the major charge transport mechanism. When redox potentials are the same on each side of the blm, the conductance of the membrane can be greater than 10(-3) S/cm2. The conductance is proportional to the second power of the concentration of Mg-C in the membrane-forming mixture. A number of additional experiments are described which attempt to elucidate the mechanism of electron transfer. We believe that our data are consistent with the idea of an electron-hopping mechanism in which the transmembrane electron transport occurs by a series of second-order electron transfers between membrane-bound electron donors (Mg-C) and acceptors (Mg-C+). Alternative explanations are presented.

[Oscillation spectra of metal-porphyrin dication spectra]. / Kolebatel'nye spektry dikationov metall-porfirinov.

Spectra of resonance spontaneous combination scattering (RSCS) of dications of metal--derivatives of tetraphenyl and ethioporphyrine (Ni-TPhP, Cu-TPhP, Cu-EP and VO-EP0 and IR-spectra of absorption of Ni-TPhP and Cu-EP dications were obtained. It was found that transformation of porphyrine neutral molecules into dications is accompanied with the appearance of new absorption bands in IR-spectra analogs of which are in RSCS spectra of dications. In some cases it points to the disturbance of alternative prohibition to oscillative transitions and to structural changes which result in the loss of symmetry centre by the molecule when it is transformed into the dication. A comparison of RSCS spectra of dications and dianions of VO-EP suggests that they have different structure.

[Absorption spectra and structure of sublimated layers of etioprophyrin and its metal derivatives]. / Spektry pogloshcheniia i struktura sublimirovannykh sloev étioporfirina i ego metalloproizvodnykh.

It has been established by means of electron and oscillation absorption spectra that the structure of sublimated layers of ethioporphyrin and its metal-derivatives depends on sublimation conditions. When sublimation was performed in a vacuum the molecules were located parallel to the base surface, in the presence of gase--at an angle, near to the right one, interlocation (and hence interaction) of molecules in the layers of different structure conditions the differences in their spectral characteristics and a peculiar anisotropy of layers. The later consists in the difference of optical properties in longitudinal and perpendicular directions to the layer surface.

[Dark transition of 1st level reduction products of porphyrins to 2d level]. / Temnovoi perekhod produktov pervogo urovnia vosstanovleniia porfirinov vo vtoroi.

Transition of the products of the first restoration of porphyrines to the second one in the darkness and practically in the absence of a reducer and oxygen has been studied. Its cause is the disproportioning of dyhydroform into tetrahydro- and the initial pigment. Regeneration of porphyrines under these conditions is also shown. The rate of both reactions significantly increases in the light.

[Intermediate reduction products of porphyrins and their structure]. / Promezhutochnye produkty reaktsii vosstanovleniia porfirinov i ikh stroenie.

It was shown on the basis of NMR-H spectra that the addition of proton to dianions of Zn-octaethylchlorine, Zn-octaethylporphin, and Zn-monoasaethioporphyrin results in the formation of products with the structure of alpha-dihydroflorine, alpha-florine, and gamma-florine respectively. This indicates that electron density greatly increases when the anions are formed in the centres which had a decreased density in the initial molecule.

[Effect of aniline and hydrazine derivatives on reversible oxygen addition in model systems of cobalt complexes of etioporphyrin and alpha, beta, gamma, delta-tetraphenylporphine]. / Izuchenie vliianiia anilina i proizvodnykh gidrazina na obratimoe prisoedinenie kisloroda v model'nykh sistemakh kobal'tovykh kompleksov étioporfirina i al'fa, beta, gamma, del'ta-tetrafenilporfina

The influence of aniline and hydrazine derivatives on the reversible oxygenation of cobaltous complexes of etioporphyrin I and alpha,beta,gamma,delta-tetraphenylporphin has been studied by means of ESR and electronic spectra. The formation of stable six-coordinated complexes with the said reagents prevents the oxygenation. The excess of hydrazines cause the destruction of porphyrin nucleus. The formation of intermediate dihydroporphyrins (chlorins) has been noticed.