bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the photodynamic action of methylene blue and zinc phthalocyanine on TG-180 tumoral cells
Authors: de Miranda Jacques Antonio , da Hora Machado Antonio Eduardo , de Oliveira Carlos Alberto
Published: July 2009

The efficiency of zinc phthalocyanine and methylene blue (CI 52015) in compromise the viability of TG 180 malignant cells by photodynamic action, was compared by counting the number of killed cells. The results show that, under the observed experimental conditions, zinc phthalocyanine ( ZnPc ) is at least two times more efficient than methylene blue (MB), and possesses a very low citotoxicity and high capacity to penetrate the cellular membrane. Quenching experiments using β-carothene evidence the importance of a type II mechanism during cell inactivation by ZnPc .
Photophysical properties of Zn(II) phthalocyaninates incorporated into liposomes
Authors: Rodriguez Myriam E. , Awruch Josefina , Dicelio Lelia
Published: July 2009

Amphiphilic phthalocyanines are used as potential photosensitizers in photodynamic therapy. The low water solubility of most of these dyes is the reason that different kinds of vehicles are employed as endogenous carriers. Due to the photophysical inactivity of the phthalocyanine aggregates, it is important to improve their solubility in order to study dyes in solid tumor models. On the other hand, the photodynamic therapy activity depends on the location of phthalocyanines in the cell and the interaction of cellular components. In this work, the photophysical properties of tetrasubstituted Zn ( II ) phthalocyanines with different lipophilic properties are incorporated into liposomes of L-α-dimyristoylphosphatidylcholine (DMPC). The fluorescence quantum yields, the association constants and their localization in the membranes are reported.
Evaluation of tetraphenyl-2,3-dihydroxychlorins as potential photosensitizers
Authors: Macalpine Jill K. , Boch Ron , Dolphin David
Published: July 2009

A series of β,β-dihydroxychlorins derived from meso-tetraphenylporphyrins (TPPs) have been synthesized. Their in vitro cytotoxicity has been measured and compared to BPDMA (verteporfin). Under the assay conditions BPDMA had an LD 50 (lethal dose to kill 50% of cells) value of 0.007 μM (5 ng/mL). The LD 50 values for the TPP derivatives varied from 1.7 × 10-2 to 9.9 μM depending upon the substituents and their position on the phenyl groups. One example of the dihydroxychlorin prepared from unsubstituted 5,15-diphenylporphyrin was examined and this exhibited an LD 50 of 2.4 × 10-3 μ M !
Spectrophotometric and electrochemical studies of the interaction between iron(II) tetrasulfophthalocyanine and histamine
Authors: Oni Joshua , Nyokong Tebello
Published: July 2009

The interaction between iron(II) tetrasulfophthalocyanine ([ Fe II TSPc ]4+) and histamine results in the oxidation of the central metal by oxygen in the former, with the formation of a complex denoted as [(His) Fe III TSPc ]3− (where His = histamine). The rate constant for the formation of the complex is kf = 2.41 × 10−2 dm 3.mol−1.s−1 and an equilibrium constant of 6.3 dm3.mol-1 was obtained. The oxidation state of the central metal of [ Fe II TSPc ]4− before and after the coordination of histamine is confirmed by spectroelectrochemistry. Further electrochemical oxidation of this [( His ) Fe III TsPc ]3− derivative results in a metal-based process proposed to involve an Fe IV phthalocyanine species.
Spectral investigations of the solution properties of 5,10,15,20-tetrakis(4-N-benzyl-pyridyl)porphyrin (TBzPyP) and its interaction with human serum albumin (HSA)
Authors: Bordbar A. Khalegh , Eslami Abbas , Tangestaninejad Shahram
Published: July 2009

The association behavior of 5,10,15,20-tetrakis(4-N-benzyl-pyridyl)porphyrin ( TBzPyP ) was investigated in aqueous solution at 27 °C and various ionic strengths by optical absorption, fluorescence and resonance light scattering (RLS) spectroscopies. The results show that TBzPyP exists as monomer at low ionic strength and as ill-defined aggregates at high ionic strength and does not show concentration dependent aggregation over an extended concentration range between 5 × 10−7 to 1 × 10−4 M in water. The interaction of the TBzPyP with human serum albumin (HSA) in 5 mM phosphate buffer, pH = 7.00, and at 27 °C, has been also studied by optical absorption, fluorescence and RLS spectroscopies. The formation of two types of complexes (HSA: TBzPyP and (HSA)2: TBzPyP ) has been demonstrated by analysis of optical absorption spectral patterns of TBzPyP at various concentrations of HSA. Based on absorption data, a binding model has been proposed and used to analyze the binding process. The calculated binding constant for formation of HSA: TBzPyP and ( HSA )2: TBzPyP are 3.79 × 106 M−1 and 1.46 × 105 M−1, respectively. The RLS spectra of TBzPyP at various concentration of HSA do not show any aggregation of TBzPyP in the presence of HSA. Due to the fact that binding of TBzPyP quenches the HSA fluorescence, a step-by-step aggregation model, which has been developed by Borissevich, I. E. et al, was used to determine the average aggregation number of HSA, < J >, from the fluorescence quenching. The < J > value is 1.4, which further confirms the formation of the two mentioned complexes at this concentration range of HSA.
Theoretical aspects of the spectroscopy of porphyrins and phthalocyanines
Authors: Stillman Martin , Mack John , Kobayashi Nagao
Published: July 2009

The development of theoretical models that describe the electronic structures of the porphyrins and phthalocyanines using ZINDO and DFT techniques is rapidly approaching the point where the major spectral bands over a wide energy range, for both symmetric and non–symmetric molecules can be fully accounted for. However, although there has been much recent progress, theoretical models should always be tested accuracy by reference to the most recent electronic absorption and magnetic circular dichroism spectra available. This must be carried out by calculating absorption spectra to determine whether the major spectral features determined are accurately described. Spectroscopists need to provide fully analyzed data for this purpose as well as data recorded at low temperatures to enhance resolution. Since the porphyrin and phthalocyanine rings readily undergo oxidation and reduction, and well-characterized spectral data are available for many different redox states, new theoretical studies should also include the bands observed in the anion and cation radical species, as well as those of the neutral complex. This symposium addresses these goals by bringing together theoreticians and experimentalists to discuss their results.
Alkyl-substituted magnesium phthalocyanine: phototoxicity after excitation of higher electronic states in cellsin vitro
Authors: Paul Andrea , Mölich Andreas , Oelckers Stefan , Seifert Martina , Röder Beate
Published: July 2009

Photodynamic tumour therapy (PDT) on the basis of a sequential two-photon excitation of suitable sensitizers is expected 1) to prevent skin phototoxicity caused by day-light and 2) may occur via an oxygen-independent mechanism of photosensitization. Here we investigated cellular uptake, localization and phototoxicity of ( t-butyl )4- PcMg , a promising dye for a sequential two-step activation, in Jurkat cells (human T cell line) and murine hybridoma cells (B cells) in vitro. Pheophorbide a (pheo) was used as a classical Type II reference sensitizer. Excitation of higher singlet states was performed both by direct UV-excitation and by sequential two-step laser excitation in the Q-band with maximum photon flux densities of about 1026phot.cm−2.s−1. Irradiation of ( t-butyl )4- PcMg in cells in vitro is accompanied by a rapid destruction of the dye, as was proved by confocal fluorescence microscopy. Irradiated cells exhibit a less pronounced decrease of viability and a transient cell cycle arrest of about 24 h. Pheo incubated cells are characterized by a complete stop of proliferation. In contrast, no long-lasting phototoxicity was observed with ( t-butyl )4- PcMg . Low fluorescence levels and rapid photobleaching prevented the identification of intracellular dye-localization. Our data indicate the presence of a radical mechanism as origin of an irreversible dye destruction that accounts for the low phototoxicity of ( t-butyl )4- PcMg .
Templated tetramerization of dicyanobenzenes to form mixed porphyrinato and phthalocyaninato rare earth(III) triple-decker complexes
Authors: Pan Na , Jiang Jianzhuang , Cui Xuegui , Arnold Dennis P.
Published: July 2009

Heteroleptic porphyrinato/phthalocyaninato rare earth(III) triple-decker compounds M 2( Por )2( Pc ') (1a-4a) and M 2( Por )( Pc ')2 (1c-4c) ( M = Eu , Tb ; Por = TDOPP , Pc ' = OOPc or Por = TpClPP , Pc ' = Pc where H 2(TDOPP) = 5,10,15,20-tetrakis(4-n-dodecyloxyphenyl)porphyrin, H2[OOPc] = 2,3,9,10,16,17,23,24-octakis(n-octyloxy)phthalocyanine, H 2(TpClPP) = 5,10,15,20-tetrakis(4-chlorophenyl)porphyrin, H 2( Pc ') = general phthalocyanine, and H 2( Pc ) = unsubstituted phthalocyanine) were obtained by the cyclic tetramerization of the corresponding dicyanobenzenes 7 using monoporphyrinato rare earth(III) acetylacetonates M(Por)acac as templates with catalysis by the organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Double-decker complexes M(Por)(Pc') ( M = Eu , Tb ; Por = TDOPP , Pc ' = OOPc or Por = TpClPP , Pc ' = Pc ) (1b-4b) were isolated as side products. For the purpose of comparative study, homo- and hetero-dinuclear rare earth triple-deckers with one porphyrinato and two phthalocyaninato ligands M2(Por)( Pc ')2 (1c, 2c) ( M = Eu , Tb ; Por = TDOPP , Pc ' = OOPc ) and ( Por ) M ( Pc ') M '( Pc ')( M ≠ M ' = Eu , Tb ) (5c, 6c) were also prepared using the raise-by-one-story method. The complexes were characterized by UV-vis, near-IR, IR and mass spectra. The comparison between 1 H NMR spectra of the two series of triple-decker compounds a and c, and also between the substituted phthalocyanine- and unsubstituted phthalocyanine-containing europium triple-deckers, renders it possible to assign the aromatic proton signals unambiguously.
Design and synthesis of a transition state analog of a metalloporphyrin-catalysed oxidation reaction
Authors: Giger Rudolf , Hoffmann Pascal
Published: July 2009

A hapten that mimics the transition state of a metalloporphyrin-catalysed oxidation reaction was synthesized in order to generate antibodies that might be able to catalyse the regioselective metalloporphyrin-co-catalysed reaction of cyclosporin A to [D-Ser8]cyclosporin A.
A calcium-bridged porphyrin coordination network
Authors: Kosal Margaret E. , Chou Jun-Hong , Suslick Kenneth S.
Published: July 2009

The hydrothermal assembly of a very stable porphyrin network with nanoscale cavities is described. A tightly packed and interpenetrated, linear polymeric framework was observed in the solid-state X-ray structure of freebase 5,10,15,20-tetrakis-(4-carboxyphenyl)porphyrin coordinated to calcium(II) ions. Strong hydrogen-bonding interactions between the coordination polymers form a two-dimensional network. Perpendicular bands interpenetrate generating an unusual three-dimensional box that clathrates a pyridine molecule.
Aggregation of meso-tetrakis(4-sulfonatophenyl)porphyrin on polyethyleneimine in aqueous solutions and on a glass surface
Authors: Castriciano Maria Angela , Romeo Andrea , Scolaro Luigi Monsù
Published: July 2009

The aggregation behavior of meso-tetrakis(4-sulfonatophenyl)porphyrin, [ H 2( TPPS 4)]4-, in the presence of hydrated polyethyleneimine ( PEI ) in aqueous solutions (1.6 < pH < 7.6) has been investigated. The interaction leads to the formation of a variety of pH dependent species, which have been attributed to porphyrin dimers or small oligomers under neutral conditions and J-aggregates on lowering the pH. The aggregation process follows kinetics typical of self-similar systems whose rates increase steeply on increasing the matrix concentration. This finding could be explained on the basis of an increased availability of binding sites for the growing aggregates. The charged polymer has been used to electrostatically adsorb the porphyrin onto glass substrates affording multilayered films. Our results point to the presence of fully protonated species in the solid state, which rearrange into J-aggregates as a function of pH and water content. The systems in solution and on glass surfaces have been investigated through a combination of UV-vis spectroscopy, fluorescence emission and resonance light scattering techniques.
New sulfonamide and sulfonic ester porphyrins as sensitizers for photodynamic therapy
Authors: Sobral Abílio J. F. N. , Eléouet Sabine , Rousset Nathalie , Gonsalves António M. d'A. Rocha , Le Meur Olivier , Bourré Ludovic , Patrice Thierry
Published: July 2009

New sulfonamide and sulfonic ester porphyrins were prepared and their in vitro characteristics as sensitizers for photodynamic therapy were assessed. Fluorescence spectra were characterised by two main peaks, located between 650-680 nm and 705-740 nm, respectively. Some of these new porphyrins (three out of nine) showed good photodynamic properties in the in vitro assays. In the absence of light, these porphyrins are not toxic. With 50 J.cm−2 illumination light (514 nm) they induced mortality in 50% of HT29 cells with 2 to 4.5 μg/ml. Comparison of in vitro phototoxic efficacy of these three compounds with other photosensitizers already described confirms interest in their phototoxic properties.
Cobalt(II)-phthalocyanine encapsulated inNaYfaujasite: aggregation ofCo(II)-phthalocyanine encapsulated inNaYzeolite due to the acidity ofTi(IV) oxide species mediated by pyridine
Authors: Prochnow Peter , Wark Michael , Schulz-Ekloff Günter , Wöhrle Dieter , Zukal Arnost , Rathousky Jiri
Published: July 2009

Co (II)-phthalocyanine ( CoPc ) was synthesized in the cages of a NaY faujasite matrix and in NaY with co-encapsulated highly dispersed Ti (IV) oxide species. As expected the encaged complexes were immobilized and could not be removed by extraction procedures. Unexpected were reversible aggregations of the CoPc molecules, revealed from DR-UV-vis spectra. The phenomena were attributed to frequently observed (i) local enrichments of the CoPc molecules, i.e., their non-uniform distribution throughout the zeolite crystals, and (ii) local damages, facilitating the contact between CoPc molecules. The aggregations are mediated by co-guests, like Ti (IV) oxide species or pyridine, i.e. by guest-guest interactions, whereas the segregation is induced by host-guest interactions between CoPc and the zeolite framework.
New polyphenylated phthalocyanine derivatives
Authors: Sooksimuang Thanasat , Behroozi Saeid J. , Mandal Braja K.
Published: July 2009

A new class of polyphenylated phthalocyanine derivatives containing near-planar aromatic rings attached to the phthalocyanine core has been synthesized. The aromatic rings contributed to a significant red shift of the Q-band absorption. Linear optical and electrochemical properties of these derivatives are described.
Columnar aggregates of crown ether substituted phthalocyanines perpendicularly anchored on a surface via a selective binding site
Authors: Thami Thierry , Chassenieux Christophe , Fretigny Christian , Roger Jean-Paul , Steybe Felix
Published: July 2009

The purpose of this work is to anchor perpendicularly to a surface the aggregates obtained by complexation of crown-ether substituted lutetium bisphthalocyanine, [(15 C 5)4 Pc ]2 Lu , in the presence of KSCN . In order to orientate these aggregates perpendicularly to the substrate, silica surface is grafted with an unsymmetrical lutetium bisphthalocyanine substituted, on one macrocycle by four crown ether subunits, and on the other one with four lateral chains terminated by a carboxylic group. The latter compound is used as a selective binding site to anchor pillar-like aggregates formed in solution. The aggregates were characterized in a mixture of chloroformic based solution by UV-visible and light scattering experiments and gave evidence for the formation of rod-like particles in the presence of excess of KSCN . Then, the aggregates were deposited on surfaces and their morphologies were studied by atomic force microscopy (AFM). In the case of substrates having non-specific binding sites such as silica and functionalized silica with 3-trimethoxy-propylaminosilane, rods were observed lying parallel on the surface. In the case of the substrate grafted with the selective binding site, single columns of these supramolecular assemblies perpendicular to the surface have been observed by AFM.
Synthesis of a new octanitroporphyrin: 5,10,15,20-tetrakis(2',6'-dinitro-3',5'-di-tert-butylphenyl)ironporphyrin
Authors: Rose Eric , Andrioletti Bruno , Pandian Ramasamy P.
Published: July 2009

Condensation of pyrrole and 3,5-di-tert-butyl-2,6-dinitrobenzaldehyde in CH 2 Cl 2 in the presence of BF 3· Et 2 O affords 5,10,15,20-tetrakis-(2',6'-dinitro-3',5'-di-tert-butylphenyl)porphyrin that can be easily metallated with Zn and Fe .
Synthesis of perylene-porphyrin dyads for light-harvesting studies
Authors: Loewe Robert S. , Tomizaki Kin-ya , Chevalier Fabien , Lindsey Jonathan S.
Published: July 2009

The spectral coverage of porphyrin-based light-harvesting arrays can be enhanced through the use of suitable accessory pigments. Perylene-monoimide dyes can serve as valuable accessory pigments with porphyrins. To investigate the choice of perylene-monoimide and the effects of molecular architecture on light-harvesting efficacy, five perylene-porphyrin dyads were prepared. Each dyad employs a diphenylethyne linker that bridges the perylene N-imide site and the porphyrin meso-position. Three dyads incorporate a mono-phenoxy perylene at the o-, m-, or p-position of the meso-aryl group on the porphyrin. The two remaining dyads incorporate a perylene-monoimide (bearing zero or three phenoxy substituents) at the p-position of the meso-aryl group on the porphyrin. The introduction of phenoxy groups on the perylenes increases the solubility, a key requirement for use in light-harvesting arrays. The long-wavelength absorption band of the perylene shifts from 506 nm to 532 or 533 nm upon substitution with one or three phenoxy groups, respectively. The synthesis of the dyads entails Pd -mediated coupling of a bromo-perylene and an ethynyl porphyrin, or the mixed-aldehyde condensation with a perylene-aldehyde, mesitaldehyde, and pyrrole. Five perylene-monoimide dyes bearing an ethyne or bromo substituent at the p-position of the N-aryl unit were developed for this modular chemistry. Each perylene-porphyrin dyad exhibits efficient energy transfer from the excited perylene to the ground-state porphyrin.
Establishing a library of porphyrin building blocks for superstructured assemblies: porphyrin dienes and dienophiles for cycloaddition reactions
Authors: Gunter Maxwell J. , Tang Hesheng , Warrener Ronald N.
Published: July 2009

The synthesis and utility of a series of porphyrins with (masked) diene and dienophile functionality are described. The key porphyrin diene is synthesised from a sulfolenopyrrole by a 3+1 strategy. A range of Diels-Alder cycloadducts is readily accessed from the diene by mild thermal extrusion of sulfur dioxide from the sulfolenoporphyrin, which produces the reactive porphodimethylidene. Each of these cycloadducts is fused to the porphyrin nucleus through a cyclohexene ring thus retaining some conformational flexibility in the resultant structures. The structures can be rigidified by mild oxidation to the corresponding benzo-derivatives. Diels-Alder reaction of the porphyrin 1,3-diene resulting from the sulfolenoporphyrin with norbornadiene produces the norbornene derivative, which can serve as a dienophile or dipolarophile in subsequent cycloaddition reactions. Nevertheless, a preferred route to this structure is through a corresponding 1+3 route, where the norbornene component is part of the tripyrrane. Extension of the synthetic protocols allows ready access to a “mixed function” porphyrin, containing both diene and dienophile components. Likewise, the synthesis of a bis-norbornene porphyrin is described. A collection of each of these reactive components is the basis for a library of building blocks which allows easy and simple entry to a wide variety of complex porphyrin-containing superstructures.
Self-assembled supramolecular triad composed of fulleropyrrolidine bearing two pyridine moieties axially coordinated to two zinc porphyrins
Authors: El-Khouly Mohamed E. , Gadde Suresh , Deviprasad Gollapalli R. , Fujitsuka Mamoru , Ito Osamu , D'Souza Francis
Published: July 2009

Spectroscopic, redox, and photochemical behavior of a self-assembled donor-acceptor triad formed by axial coordination of zinc meso-tetraphenylporphyrin, Zn ( TPP ) with fulleropyrrolidine bearing two pyridine moieties ( C 60( Py )2) was investigated. The UV-visible and 1 H NMR spectral studies revealed supramolecular 1:2 triad formation between C 60( Py )2 and Zn ( TPP ). The determined overall formation constant, K was as large as 1.45 × 104 mol -2 in o-dichlorobenzene (o-DCB). The 1 H NMR studies revealed axial coordination of both the pyridine entities of C 60( Py )2 to the central metal ion of the zinc porphyrins. Electrochemical studies of the isolated self-assembled triad in o-DCB established the molecular stoichiometry of the supramolecular complex possessing one C 60( Py )2 and two Zn ( TPP ) entities. The excited state electron transfer reactions were monitored by both steady-state emission as well as transient absorption techniques. In o-DCB, upon coordination of the pyridine entities of C 60( Py )2 to two Zn ( TPP ), the main quenching pathway involved charge-separation from the singlet excited Zn ( TPP ) to the C 60 moiety. However, in a coordinating solvent like PhCN , intermolecular electron-transfer takes place from the triplet excited state of Zn ( TPP ) to the C 60 moiety.
Synthetic and structural studies on metal complexes of tripyrrin
Authors: Bröring Martin , Brandt Carsten D. , Prikhodovski Serguei
Published: July 2009

A general two-step procedure for the synthesis of metallotripyrrinates TrpyMOAc f with M = Co(II) , Cu(II) , Zn(II) and Pd(II) , and OAc f = trifluoroacetate, is described, starting from well-known monopyrrolic precursors and simple transition metal acetates. X-ray structural investigations were undertaken on four different complexes, and the results reveal, that the nature of the metal ion, rather than the ligand, determines the coordination geometry of these porphyrin fragment complexes. The finding of pseudotetrahedral and strained pseudoplanar coordination polyhedra at the metal centres makes a clear distinction between metalloporphyrins and metallotripyrrins and shows the latter to be related to some recently discovered metal chelates of macrocyclic porphyrin analogues.
Oxygen evolution sensitized by tin porphyrin in microheterogeneous system and membrane systems
Authors: Wang Sheng , Hori Teruo
Published: July 2009

Tin porphyrin ( SnTPP ) was applied to two new types of photoinduced oxygen evolution systems by visible light irradiation. In microheterogeneous system, tin porphyrin was dispersed by a nonionic surfactant and the system could efficiently oxidize water to evolve oxygen when compared with the conventional system. In addition, two types of tin porphyrin fixed PVC membranes, porous and homogeneous, were prepared and applied to a photoinduced oxygen evolution membrane system. SEM images of two types of tin porphyrin fixed PVC membranes also show differences in both morphologies.
Solvent effects of cobalt(II) phthalocyanine in sulfuric acid: a continuous wave and pulse EPR study
Authors: Finazzo Cinzia , Doorslaer Sabine Van , Schweiger Arthur
Published: July 2009

Products based on metal phthalocyanines are widely used in industry. In the processing of these materials it is essential to control the conditions of the matrix the metal phthalocyanines are embedded in. Using the example of cobalt(II) phthalocyanine in sulfuric acid we show that continuous wave and pulse electron paramagnetic resonance and electron nuclear double resonance spectroscopy provide excellent tools to monitor the influence of the matrix on paramagnetic phthalocyanines. The g values, the cobalt hyperfine values, and the hyperfine and nuclear quadrupole couplings of the isoindole nitrogens, as well as the hyperfine interactions of the surrounding protons allow for a detailed assessment of the electronic structure of cobalt(II) phthalocyanine in sulfuric acid. Subtle differences between the system under study and related Co ( II ) porphyrin and corrin systems could be traced.
The synthesis of phthalocyanines containing both nitrile and non-peripheral alkyl or alkoxy side-chains
Authors: Makhseed Saad , McKeown Neil B.
Published: July 2009

The synthesis of a number of phthalocyanines containing four or eight peripheral nitrile groups in addition to eight non-peripheral alkyl or alkoxyl side-chains is described. These materials are derived from the tetracyano- and tricyano-benzene derivatives prepared by the Rosenmund von Braun reaction of 1,2,4,5-tetrabromo-3,6-didodecylbenzene or 1,2,4,5-tetrabromo-3,6-hexyloxybenzene. Attempts to polymerise 1,2,4,5-tetracyano-3,5-didodecylbenzene to form a soluble polyphthalocyanine derivative failed.
Dye-sensitized solar cell with the near-infrared sensitization of aluminum phthalocyanine
Authors: Komori Tasuku , Amao Yutaka
Published: July 2009

The dye-sensitized solar cell (DSSC) using visible and near-infrared sensitization of nanocrystalline TiO 2 films using a series of four aluminum phthalocyanines was developed and its photoelectrochemical properties were investigated. By using aluminum 2,9,16,23-tetrakis(phenyl-thio)-29H,31H-phthalocyanine chloride adsorbed on a nanocrystalline TiO 2 film electrode, the I SC , V OC , FF , P max and η values were largest compared with the other DSSCs using aluminum phthalocyanines. For all the DSSCs using aluminum phthalocyanines, IPCE values at near-infrared region (700 nm) are larger than those at visible region (500 nm). Thus, the DSSC using near-infrared sensitization of nanocrystalline TiO 2 film by aluminum phthalocyanines was developed.
Synthesis of 1,2-bis(3,4-dicyanophenoxymethyl)benzene and binuclear zinc phthalocyanines of clamshell and ball types
Authors: Tolbin Alexander Yu. , Ivanov Alexey V. , Tomilova Larisa G. , Zefirov Nikolai S.
Published: July 2009

A novel 1,2-bis(3,4-dicyanophenoxymethyl)benzene was synthesized from 1,2-bis-(hydroxymethyl)benzene and 4-nitrophthalodinitrile. Its condensation with 4-tert-butylphthalodinitrile results in a binuclear phthalocyanine of clamshell type. Reaction of bisphthalodinitrile with a large excess of zinc acetate gives rise to a binuclear phthalocyanine of ball type (33% yield). The successful syntheses of these binuclear phthalocyanines were carried out by microwave irradiation and solid phase methods.
Spectroscopic studies on the selective inclusion of amphiphilised porphyrin derivatives in micellar phases
Authors: Monti Donato , Pastorini Alessandra , Venanzi Mariano , Borocci Stefano , Mancini Giovanna
Published: July 2009

The inclusion behavior of [5-(4-(3-trimethylammonium)propyloxyphenyl)-10,15,20-tryphenylporphyrin] chloride( 1H 2), 2-[2-(2-(4-(10,15,20-triphenyl-5-porphyrinyl)-phenoxy)-ethoxy)ethoxy]ethanol (2 H 2), and their Mn ( III ) derivatives, 1MnCl and 2MnCl, respectively, in micellar phases of CTAB and Brij 35 aqueous solutions has been studied by means of several spectroscopic techniques. The results obtained show that a suitable functionalisation of the periphery of the porphyrin macrocycle influences the specificity of their binding to different micellar aggregates. This, consequently, allows for a tuning of the location and the aggregation mode of inclusion. These findings give a sound basis for the interpretation of the, earlier reported, P450 biomimetic catalytic activity featured by 1MnCl and 2MnCl in the epoxidation of some probe olefins.
Hydrogen evolution sensitized by tin porphyrin fixed membranes
Authors: Wang Sheng , Tabata Isao , Hisada Kenji , Hori Teruo
Published: July 2009

A novel, photoinduced hydrogen evolution system involving a tin porphyrin ( SnTPP ) fixed membrane was studied with two different types of PVC membranes: homogeneous and porous. It was found that the porous PVC membrane system could efficiently reduce water to evolve hydrogen compared with the homogeneous type. The results confirmed that hydrogen evolution in the SnTPP / PVC membrane system depended strongly on the surface of the membrane and the degree of aggregation of SnTPP . SEM images of the two types of SnTPP / PVC membranes also show the differences in both morphologies.
Photophysical properties of self-assembling porphinatozinc and photoinduced electron transfer with fullerenes
Authors: Itou Mitsunari , Fujitsuka Mamoru , Araki Yasuyuki , Ito Osamu , Kido Hiroaki
Published: July 2009

Photochemical and photophysical properties of self-assembling 5-(4-pyridyl)-10,15,20-triphenylporphinatozinc ( Znpyp 3) have been studied by steady-state and time-resolved absorption in addition to time-resolved fluorescence spectroscopy. Self-assembling oligomers ( Znpyp 3)n( n = 3 at 0.1 mM) were synthetically generated and assigned to a zigzag chain oligomeric structure, where n is dependant on the concentration and temperature. The lifetimes of the singlet and triplet excited states of ( Znpyp 3)n depend on n and the axial ligation. The rate-constant of ( Znpyp 3)n for the intermolecular T-T annihilation process was smaller than that of monomeric porphyrins. In the photoinduced electron-transfer to fullerenes ( C 60 and C 70), it was revealed that the rate-constants and efficiencies for ( Znpyp 3)n were essentially the same as those of the monomer. In the back electron transfer, the rate-constants of oligomers were smaller than that of the monomeric porphyrin, which suggests hole-delocalization along the porphyrin chain.
Synthesis and multilayer assembly of multiporphyrin arrays at the water-chloroform interface
Authors: Qian Dong-Jin , Nakamura Chikashi , Wakayama Tatsuki , Miyake Jun
Published: July 2009

A water-chloroform interface was developed for the synthesis and assembly of the cadmium-mediated multiporphyrin arrays. With the use of a vertical dipping method, multilayers of the multiporphyrin can be deposited onto hydrophobic substrate surfaces. An in situ absorbance measurement at the water-porphyrin chloroform interface revealed a blue shift for the porphyrin Soret band after the addition of CdCl 2 into the water phase. The transferred multilayers showed a broad Soret band from 430 to 442 nm, which is ascribed to monomer-like porphyrin arrangement in the planar layer and aggregates in the interlayer. The orientation angle of porphyrin macrocycles is about 30°. The porphyrin emission properties in the present multilayers are compared to those in the monomer and aggregate prepared from the air-water/ CdCl 2 subphase surfaces.
X-ray structures and luminescence properties of Co(II) and Co(III) complexes of cofacial diporphyrins
Authors: Bolze Frédéric , Drouin Marc , Harvey Pierre D. , Gros Claude P. , Espinosa Enrique , Guilard Roger
Published: July 2009

The crystal structures of two face-to-face diporphyrin compounds based upon the DPA ligand (1,8-bis(5-(2,8,13,17-tetraethyl-3,7,12,18-tetramethyl-porphyrinyl))anthracene), i.e. H 4( DPA ) and ( DPA ) Co 2 are reported. The structural data are compared to that of other bimetallic DPA systems, and diporphyrinic Co complexes. In addition, the luminescence properties of ( OEP ) Co ( OEP = 2,3,7,8,12,13,17,18-octaethylporphyrin), H 2( DPA ) Co , H 2( DPA )( CoIm ) O 2, ( DPA ) Co 2, ( DPA )( CoIm )2 O 2 are reported, where Im is 1-t-butyl-5-phenyl imidazole. Contrary to previous literature reports, the Co (II) species are found to be weakly luminescent, where fluorescence is detected for both the mono- and diporphyrinic systems, and is assigned to emissions arising from the lowest 1 Q (ππ*) states, while phosphorescence is detected at 77 K only for the monoporphyrin species, ( OEP ) Co . On the other hand, the Co (III) complexes are not luminescent.
Fate of nickel and cobalt sulfophthalocyanines under oxidizing conditions: a spectroscopic investigation
Authors: d'Alessandro Nicola , Tonucci Lucia , Dragani Luana K. , Morvillo Antonino , Bressan Mario
Published: July 2009

Two water-soluble metal sulfophthalocyanines, namely Ni (II) PcS and Co (II) PcS , were structurally characterized by electrospray ionization mass spectrometry (ESI-MS) and UV-vis and NMR spectroscopy. The dominant ion in ESI-MS was a penta-protonated monomeric Ni (II) complex and a tetra-protonated form with the Co (II) ion being oxidized to Co (III), confirming the facile oxidation of the central cobalt atom of the phthalocyanine ring by a soft ionization method as ESI. Experiments at various ESI voltages were also performed to ascertain the target of the oxidation, whether it was the metal or the phthalocyanine unsaturated system. Addition of small amounts of oxidizing agents, like potassium persulfate, resulted in a definite attenuation of the Q band in the UV-vis spectra, while ESI-MS detected a variety of complexes, containing at least one oxygen atom, which rapidly replaced the initial complexes.
Synthesis, spectral and electrochemical properties of a new family of pyrrole substituted cobalt, iron, manganese, nickel and zinc phthalocyanine complexes
Authors: Obirai Joe , Rodrigues Nazaré Pereira , Bedioui Fethi , Nyokong Tebello
Published: July 2009

A new family of pyrrole substituted metallophthalocyanine complexes, namely cobalt(II), iron(II), manganese(III), nickel(II) and zinc(II) tetrakis-4-(pyrrol-1-yl)phenoxy phthalocyanines (noted as M ( TPhPyrPc ), where M is the metallic cation) have been synthesized and fully characterized. In particular, the UV-visible spectra of the iron and nickel complexes showed extensive aggregation even at low concentrations. The cyclic voltammetry of the cobalt, iron and manganese complexes showed three to four redox couples assigned to metal and ring based processes. Spectroelectrochemistry of the manganese derivative confirmed that the synthesized complex is Mn III( TPhPyrPc -2) and that the reduction of Mn II( TPhPyrPc -2) to be centred on the ring and rather than on the metal, forming the Mn II( TPhPyrPc -4) species. Also, the electrochemical polymerization of these newly synthesized pyrrole-substituted phthalocyanines has been demonstrated in the case of the cobalt complex and the electrocatalytic activity of the obtained film has been tested towards the oxidation of L-cysteine.
Electronic absorption spectra of substituted phthalocyanines in solution and as films
Authors: Ogata Hiroshi , Higashi Ryuji , Kobayashi Nagao
Published: July 2009

The electronic absorption spectra of several phthalocyanines substituted at the so-called α-, β- and α and β-positions of the macrocycle have been recorded in solution and as films (α = 1,4,8,11,15,18,22, and 25 positions or 1,8 (or 11),15 (or 18), and 22 (or 25) positions, and β = 2,3,9,10,16,17,23, and 24 positions or 2,9 (or 10),16 (or 17), and 23 (or 24) positions). Phthalocyanines substituted with bulky groups at the α-positions prevent cofacial aggregation so that their Q-absorption band remains at a similar wavelength both in solution and films, although the film spectra are generally broader. Phthalocyanines substituted at the β-positions are apt to aggregate cofacially in polar solvents but in films they may show broad Q-bands which spread out to both shorter and longer wavelengths of the solution Q-band, depending on the bulkiness of the substituents. The film spectra of hexadeca-substituted phthalocyanines exhibit Q-bands at a similar wavelength as in solution, with insignificant broadening of the Q-band on film formation. However, the Soret bands for most of the substituted phthalocyanines are shifted and broadened to longer wavelength in the films.
Synthesis of tailored phthalocyanines and their application as spin coated films in volatile organic compound detection
Authors: Spadavecchia Jolanda , Ciccarella Giuseppe , Buccolieri Alessandro , Vasapollo Giuseppe , Rella Roberto
Published: July 2009

29H,31H-(2,4-di-t-amylphenoxy)phthalocyanine, Zn (II) tetra-4-(2,4-di-t-amylphenoxy) phthalocyanine and Zn (II) tris-(2,4-di-t-amylphenoxy)-[4-(4-mercapto-phenyliminomethyl)- phenoxy]phthalocyanine were synthesized and their molecular structures were confirmed by LC-MS, 1 H NMR, FT-IR and UV-vis spectra. Spin coated layers of these phthalocyanines have been used as optochemically interactive materials for volatile organic compounds detection in the UV-vis spectral range. The results show a good sensitivity and selectivity depending on both the metal and the peripheral substituents. Optical sensitivity towards tert-butylamine, diethylamine, dibutylamine, 2-butanone and acetic acid has been monitored.
Syntheses and photochemical properties of a tribenzo-naphtho-condensed porphyrazinatozinc complex
Authors: Pelisson Marcelo M. M. , Tomé Fernanda M. , Beltrame Milton , Simioni Andreza R. , Tedesco Antonio C.
Published: July 2009

The synthesis of a zinc derivative of tribenzonaphthoporphyrazinato ( Zn -tri- PcNc ) obtained from 6-carboxymethyl-2,3-dicyanonaphthalene and phthalonitrile is described. This new phthalocyanine ( Pc ) compound was characterized by 1 H NMR, elemental analyses, IR and UV-vis. The spectroscopic analysis of this compound show an electronic spectrum in DMSO with characteristic bands in the Soret and ϱ region. Steady state and time-resolved spectral analysis revealed a fluorescence quantum yield and a fluorescence lifetime of Φf=0.22 and τf = 2.56 ns respectively, in agreement with other Pc derivatives. This compound also shows a triplet lifetime in air satured solutions of 1.06 μs and a transient with the maximum absortion located at 610 nm, 120 nm shifted to the red compared to the triplet observed by other Pc compounds.
Long-lived photoinduced charge transfer state of synthetically affable porphyrin-fullerene dyads
Authors: Montforts Franz-Peter , Vlassiouk Ivan , Smirnov Sergei , Wedel Michael
Published: July 2009

Bislactone linked porphyrin-fullerene dyads show promising photophysical properties for mimicking photosynthesis. Optical and transient displacement current investigations of the dyads demonstrate efficient intramolecular electron transfer from porphyrin to fullerene with the lifetime of the charge transfer state on the order of a few nanoseconds in low polarity solvents. Solvent polarity effect on the yield of charge separation and conformations in the charge transfer state are investigated in detail. The facile synthesis could readily be applied to constructing extended compounds with high yields of photoinduced charge separation.
Studies on the mechanism of the reaction of tetrakis({1-me-thylpyridinium-4-yl}porphyrinato)iron(III) pentaperchlorate with hydrogen peroxide
Authors: Saha Tapan K. , Karmaker Subarna , Tamagake Keietsu
Published: July 2009

The reaction of the 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrinatoiron(III) cation, [ FeIII( TMPyP )]5+(1; prepared as the pentaperchlorate), with hydrogen peroxide ( H2O2) in aqueous solution was studied by spectrophotometric methods. The porphyrin 1 was rapidly oxidized with an excess of H2O2under aerobic conditions to the oxo-iron(IV) porphyrin, [ FeIVO ( TMPyP )]4+(2), having UV-visible absorption maxima at 436 and 450 nm. Computer deconvolution of the time-resolved absorption spectra revealed that the absorption spectra < 0.5 s were not reproduced well by a simple combination of the two spectra of 1 and 2, indicating that transient species were formed at the initial stage. Addition of sodium nitrite ( NaNO2), which is thought to be a one-electron donor, to the stoichiometric reaction mixture of 1 and H2O2increased the initial formation rate of 2. The presence of uric acid (UA) caused a significant delay in the formation of 2. The delay of the appearance of 2 was directly proportional to the starting concentration, [ UA ]0, but other kinetic profiles were not changed significantly. Based on these observations and the kinetic analysis, we confirmed the involvement of the oxo-iron(IV) porphyrin radical cation, [ FeIVO ( TMPyP•)]5+(3), as a compulsory intermediate in the rate-determining step of the overall reaction, 1 + H2O2→ 2, with a rate constant k = 4.4 × 104M−1.s−1. The rate constants for the reaction between 2 and NaNO2, and between 2 and UA were estimated to be 9.0 M−1s−1and 5.45 × 106M−1.s−1, respectively.
Gallium(III) corroles
Authors: Weaver Jeremy J. , Sorasaenee Karn , Sheikh Mayra , Goldschmidt Ruth , Tkachenko Elena , Gross Zeev , Gray Harry B.
Published: July 2009

Gallium(III) corroles are closed-shell analogs of zinc(II) porphyrins. These intensely fluorescent molecules can be modified readily to tune their solubility and photophysical properties. A water-soluble gallium corrole has been synthesized and investigated in depth; it binds tightly to human serum albumin, opening the possibility of using corroles as therapeutic agents as well as probes of biological structures.
meso-aryl expanded porphyrins: synthesis, structures, and coordination chemistry
Authors: Shimizu Soji , Osuka Atsuhiro
Published: July 2009

meso-aryl expanded porphyrins, that can be regarded as real homologues of meso-tetraaryl porphyrins, were prepared by our synthetic protocol under the modified Rothemund-Lindsey conditions. This new class of molecules exhibits interesting spectral, electrochemical, and coordination properties. These promising features are emphasized, with a particular attention on the annulenic properties.
Cytochrome c folding / unfolding: a unifying picture
Authors: Bertini Ivano , Rosato Antonio , Turano Paola
Published: July 2009

Recent NMR structural and dynamical data on partially folded forms of mono-heme cytochrome c provide a unifying picture of the behavior of the protein far from the native conditions and suggest useful hints to explain the redox dependent stability of the protein. A fragile hinge in the structure of mitochondrial cytochrome c is identified, which may not have correspondents in smaller type-1 cytochromes. Former spectroscopic and kinetic data are here discussed in terms of this new view.
Modeling heme protein active sites with the his93gly cavity mutant of sperm whale myoglobin: complexes with nitrogen-, oxygen- and sulfur-donor proximal ligands
Authors: Perera Roshan , Dawson John H.
Published: July 2009

Recent investigations of the His93Gly (H93G) "cavity" mutant of myoglobin as a versatile scaffold for modeling heme states are described. The difference in accessibility of the two sides of the heme in H93G myoglobin makes it possible to generate mixed ligand adducts in the ferric state that are difficult to prepare with heme models in organic solvents. In addition, the protection provided to the heme by the protein environment allows for the preparation of stable oxyferrous and oxo-iron(IV) complexes at near-ambient temperatures with variable ligands trans to the normally reactive dioxygen and oxo substituents. The extensive range of possible complexes that can be generated using the H93G system is illustrated with examples involving imidazole, phenolate, benzoate, thiolate and thiol ligands bound to the proximal side of the heme iron.
Phthalocyanines as materials for advanced technologies: some examples
Authors: Dini Danilo , Hanack Michael
Published: July 2009

Metallophthalocyanine complexes and related compounds play an important role in many advanced applications and modern technologies mostly by virtue of their characteristic optical absorption and high chemical stability. As a class of materials made well-known by their vivid and fast colors, it is expected that metallophthalocyanines and analogues, e.g. naphthalocyanines, are going to keep their role with the increasing use of natural and artificial light in the technologies of the future. In the present review some relevant properties of phthalocyanines and related macrocycles for technological applications are analyzed. In particular the electrical conductivity and photoconductivity as well as some nonlinear optical properties (mostly optical limiting), of phthalocyanines and related compounds are discussed.
Synthetic transformations of porphyrins – Advances 2002-2004
Authors: Senge Mathias O. , Richter Julia
Published: July 2009

Contemporary methods for the modification of porphyrins are presented. In association with the Third International Conference on Porphyrins and Phthalocyanines (ICPP-3) a survey of current method developments and reactivity studies is made. The review focuses on synthetic transformations of porphyrins currently in use for various applications and on functional group transformations. A brief survey of important developments covers selectively the literature from late 2001 to early 2004.
Strategies for selective delivery of photodynamic sensitisers to biological targets
Authors: Hudson Robert , Boyle Ross W.
Published: July 2009

Strategies for increasing the affinity of photodynamic sensitisers for specific tissues, cells and organisms are reviewed. Biological outcomes are evaluated and therapeutic potential assessed.
The renaissance in optical spectroscopy of phthalocyanines and other tetraazaporphyrins
Authors: Nyokong Tebello , Isago Hiroaki
Published: July 2009

Spectral properties of metallophthalocyanines and other tetraazaporphyrins are governed mainly by the Q band which originates from the π-π* transitions within the ring. The position and intensity of the Q band is important in tailoring new phthalocyanine derivatives for particular applications. Aggregation, the nature of the central metal, π conjugation, symmetry of the molecules, and axial, peripheral or non-peripheral substitutions affect the spectra and hence the properties of the phthalocyanine molecule. This review gives a brief outline on how optical spectroscopy provides useful informations on molecular and electronic structures, chemistry and physics of phthalocyanines and other tetraazaporphyrins.
The chemistry of porphyrazines: an overview
Authors: Rodríguez-Morgade M. Salomé , Stuzhin Pavel A.
Published: July 2009

The main synthetic approaches for the preparation of porphyrazines are outlined. In addition, some structural and spectroscopic properties, especially the UV-vis absorption profiles emanating from their peripheral functionalization, the modification of the tetraazaporphyrin skeleton or the arrangement of macrocycles in a supramolecular manner, are discussed. Cyclotetramerization of appropriate dinitrile derivatives or modification of peripheral substituents on porphyrazines constitute the main synthetic routes. Moreover, the use of special templates, as well as different intermediates or nonpyrrolic precursors, are tools for the attainment of azaporphyrin analogues of distinct nature and unusual characteristics.
Structural stabilities of N-permethylated tetracations of meso-tetrakis(4-pyridyl)porphyrin, meso-tetrakis[4-(dimethylamino)phenyl]porphyrin, and their manganese(III) complexes toward hydrogen peroxide, tert-butylhydroperoxide, and sodium hypochlorite
Authors: Türk Hayrettin , Erdem Murat
Published: July 2009

The degradation rate constants of the tetracations 5,10,15,20-tetrakis( N -methylpyridinium-4-yl)porphyrin and 5,10,15,20-tetrakis( N , N , N -trimethylanilinium-4-yl)porphyrin as well as their manganese(III) complexes toward the oxidants H 2 O 2, t- BuOOH , and NaOCl were measured at various pH values, I = 0.2 M and 30°C. The free-base and manganese porphyrins showed high structural stabilities toward H 2 O 2 and t- BuOOH in strong acidic solutions and their degradation constants were on the order of 10-6 min-1 or no porphyrin degradation was observed at all. As the pH increased, their stability towards these peroxides decreased and in basic solutions, they showed almost no stability toward H 2 O 2 and a moderate stability toward t- BuOOH . When NaOCl was employed as the oxidant, they showed only moderate stabilities in strong basic solutions and almost no stability in slightly basic, neutral or acidic solutions. The degradation rate constants in the presence of NaOCl in strong basic solutions varied from 10-2 min-1 to 10-4 min-1.