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  • A survey of acid catalysts in dipyrromethanecarbinol condensations leading to meso-substituted porphyrins
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2001-12-31
    G. Richard Geier, Jennifer B. Callinan, Polisetti Dharma Rao, Jonathan S. Lindsey

    The successful use of dipyrromethanecarbinols in rational routes to porphyrinic macrocycles requires catalysis conditions that enable irreversible condensation, thereby avoiding substituent scrambling and formation of undesired porphyrin products. Previously, successful conditions of trifluoroacetic acid (TFA) (30 mM) in acetonitrile were identified following a lengthy survey of TFA and BF3-etherate catalysis in diverse solvents. In this study, focus was placed on the acid catalyst by examining 17 acids in CH2Cl2, the traditional solvent for two-step, one-flask porphyrin syntheses. In the self-condensation of the carbinol derived from 1-(4-methylbenzoyl)-5-phenyldipyrromethane, porphyrin yields of 9–55% were obtained from the various acids, compared to 20% under TFA catalysis­in acetonitrile. A number of catalytic conditions that produce little to no porphyrin in reactions of pyrrole + benzaldehyde afforded good yields of porphyrin and the suppression of scrambling in reactions of dipyrromethanecarbinols. The four best acid catalysts (InCl3, Sc(OTf)3, Yb(OTf)3, and Dy(OTf)3) initially identified were then examined with dipyrromethanecarbinols bearing challenging substituents (alkyl, pyridyl, or no substituent). The greatest improvement was obtained with the pyridyl substrates. Selected reactions performed on a preparative scale (115 to 460 mg of isolated porphyrin) verified the results of the analytical-scale experiments and revealed the more facile isolation of the porphyrin from reactions performed in CH2Cl2 rather than acetonitrile. This study provides alternatives to the use of TFA/acetonitrile that offer advantages in terms of yield and isolation of the porphyrin without sacrificing suppression of scrambling. Furthermore, the finding that poor catalysts for the benzaldehyde + pyrrole reaction can be excellent catalysts for dipyrromethanecarbinols provides guidance for the identification of other catalysts for use with reactive precursors in porphyrin-forming reactions. Copyright © 2001 John Wiley & Sons, Ltd.

    更新日期:2017-12-14
  • Evaluation studies of technetium-99m-porphyrin (T3,4BCPP) for tumor imaging
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2001-12-31
    Murugesan Subbarayan, S. J. Shetty, T. S. Srivastava, O. P. D. Noronha, A. M. Samuel

    A water-soluble porphyrin, 5,10,15,20-tetrakis[3,4-bis(carboxymethyleneoxy)phenyl] porphyrin (T3,4BCPP), was successfully labeled with 99mTc and biodistribution studies were performed in Wistar rats. Scintiimaging and in vivo distribution studies were also carried out in C6-gliomas and mammary tumor-bearing animals using a gamma camera. Tumor-to-muscle (T/M) ratios were calculated and compared with those obtained with the known tumor-seeking radiopharmaceuticals 99mTc(V)-DMSA (DMSA = dimercaptosuccinic acid), 99mTc-citrate and 201TlCl. In the case of C6-gliomas, the ratios were 4.2, 2.2, 4.00 and 3.0; while in the case of C3H/J mammary tumor, the ratios were 9.4, 8.8, 8.1 and 8.5 for T3,4BCPP, 99mTc(V)-DMSA, 99mTc-citrate and 201TlCl, respectively. Similar studies were carried out in N-methyl-N-nitrosourea (NMU)-induced mammary tumor animals and the T/M ratios obtained were 5.9, 2.0, 5.3 and 3.3 for T3,4BCPP, 99mTc(V)-DMSA, 99mTc-citrate and 201TlCl, respectively. The radiolabeled photosensitizer could perhaps be used to detect cancer non-invasively and could even prove useful in monitoring the progression/regression of tumors before, during, and after chemotherapy, radiation therapy or photodynamic therapy (PDT). Copyright © 2001 John Wiley & Sons, Ltd.

    更新日期:2017-12-14
  • Kinetics of zinc ion incorporation in base into a centrally aprotic beta-octabrominated cationic water-soluble porphyrin and its monolithium complex
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2001-12-31
    Sabrina L. Bailey, P. Hambright

    The kinetics of zinc incorporation from pH 12 to 13 into the centrally aprotic BrP(4)2+ form of beta-octabromo-meso-tetrakis(N-methyl-4-pyridyl)porphyrin and its monolithium complex were studied at 25.0 °C, ionic strength (I) = 0.10. The reactions were first order in porphyrin and total zinc concentrations. For BrP(4)2+, the specific rate constant was 5.1 × 105 M−1 s−1 for Zn(OH)2aq, 9.9 × 104 M−1 s−1 for , and was unreactive. The Li-BrP(4)3+ complex had a formation constant with BrP(4)2+ of 1.1 × 103 M−1 from both kinetic and equilibrium measurements. In solutions containing both BrP(4)2+ and Li-BrP(4)3+, zinc incorporation proceeded only through BrP(4)2+. Copyright © 2001 John Wiley & Sons, Ltd.

    更新日期:2017-12-14
  • Synthesis of N-phytochlorin-substituted [60]fulleropyrrolidines
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2001-12-31
    Alexander Efimov, Nikolai V. Tkatchenko, Pirjo Vainiotalo, Helge Lemmetyinen

    A series of new phytochlorin–fullerene dyads was prepared. Synthetic pathway includes attachment of glycine to aldehyde-containing phytochlorins via reductive amination, where 3- and 7-carbonyl-substituted pheophorbides exhibit surprisingly different reactivity. The appropriate conditions of reactions (e.g. solvents and reducing agents) were determined in each case. Copyright © 2001 John Wiley & Sons, Ltd.

    更新日期:2017-12-14
  • Spectroscopic studies of the interaction of cobalt(II) N,N′,N″,N″′-tetramethyltetra-3,4-pyridinoporphyrazine with amino acids and nitrogen oxides
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2001-12-31
    Mamothibe A. Thamae, Tebello Nyokong

    The interaction of histidine, cysteine, NO and nitrite with cobalt(II) N,N′,N″,N″′-tetramethyltetra-3,4-tetrapyridinoporphyrazine ([CoIItmtppa]4+) is reported. Metal-based autoreduction of [CoIItmtppa]4+ occurs with the formation of the [CoItmtppa(−2)]3+ species in the presence of histidine and cysteine. Kinetic data for the auto reduction of [CoIItmtppa]4+ in the presence of these amino acids gave the rate constants kf = 2.1 × 101 and 2.8 dm3 mol−1 s−1, for cysteine and histidine, respectively. One molecule of NO or nitrite was found to coordinate to the [CoIItmtppa]4+ species. The equilibrium and rate constants for the coordination of the nitric oxide were K = 2.3 × 104 dm3 mol−1 and kf = 7.5 dm3 mol−1 s−1, respectively. The coordination of nitrite to [CoIItmtppa]4+ occurred with an equilibrium constant of K = 2.0 × 102 dm3 mol−1 and a rate constant of kf = 4.0 × 10−3 dm3 mol−1 s−1. There was no evidence for the coordination of two molecules of nitrite to the [CoIItmtppa]4+ species. Copyright © 2001 John Wiley & Sons, Ltd.

    更新日期:2017-12-14
  • A non-tetradecarboxylative synthesis of ­2,7,12,17-tetraphenylporphycene
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2001-12-31
    Ana Gavalda, JosÉ I. Borrell, Jordi Teixido, Santiago Nonell, Ofir Arad, Roser Grau, Magdalena CaÑete, Angeles Juarranz, Angeles Villanueva, Juan C. Stockert

    A new synthetic method for 2,7,12,17-tetraphenylporphycene (2e, TPPo) which avoids tetradecarboxylation by sublimation of the intermediate tetracarboxylic acid 8 is reported. Thus, the use of a pyrrol 13a bearing two orthogonal ester groups allows the synthesis of bipyrrol 12a, from which the benzyl ester groups are selectively removed to afford diester 11. The latter is transformed to dialdehyde 10 by using the McFayden–Stevens reaction, thus avoiding the unstable bipyrrol 9 formed during the tetradecarboxylation of 8. Copyright © 2001 John Wiley & Sons, Ltd.

    更新日期:2017-12-14
  • PDT-related photophysical properties of conformationally distorted palladium(II) porphyrins
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2001-12-31
    A. Wiehe, H. Stollberg, S. Runge, A. Paul, M. O. Senge, B. RÖder

    The photodynamic therapy (PDT) related photophysical properties of five palladium(II) porphyrins with increasing steric demand of the meso-substituents were investigated by steady state and time-resolved absorption and luminescence spectroscopy. The steric strain of the meso-substituents is reflected in a bathochromic shift of the B-band in the absorption spectra. In contrast to free-base porphyrins, the palladium(II) complexes exhibit only a very weak fluorescence with ΦFl ∼10−4. Instead, the corresponding triplet states of the porphyrins are formed via inter system crossing (ISC) with a quantum yield ΦISC of nearly unity. A phosphorescence quantum yield ΦISC of 10−4 was determined assuming dynamic quenching. The triplet state of all compounds is efficiently quenched by molecular oxygen, generating singlet molecular oxygen with a quantum yield of ΦΔ ∼0.85. The various substitution patterns exerted no significant influence on the ISC rates or singlet oxygen quantum yields. Significant differences, on the other hand, were observed with respect to the triplet lifetimes, with a tendency of longer lifetimes for the porphyrins with sterically more demanding substituents (in air-saturated solution). All porphyrins were successfully incorporated into liposomes. The phototoxic activity of three compounds was investigated in cell suspensions. The use of the new porphyrinato-palladium(II) in PDT applications is discussed. Copyright © 2001 John Wiley & Sons, Ltd.

    更新日期:2017-12-14
  • 5,15-Diaryl-β-substituted-porphyrinato-manganese(III) chlorides as probes for structure–activity relationships in porphyrin-based epoxidation catalysts
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2001-12-31
    Abílio J. F. N. Sobral, António M. d'A. Rocha Gonsalves

    Manganese complexes of 5,15-diaryl-β-substituted-porphyrins were prepared and their behaviour as oxidation catalysts was studied. The role of the pyrrolic and meso-substituents on the activity and selectivity of these catalysts was studied to reveal new structure–activity relationships in these porphyrin-based epoxidation catalysts. The beneficial effect of the halogen atoms at the meso-phenyls is still observed with these catalysts but, for the first time, a strong dependence on the selectivity of the epoxide production was found to be dependent on the nature of the non-halogen substituents at the β-pyrrolic positions of the porphyrin. Copyright © 2001 John Wiley & Sons, Ltd.

    更新日期:2017-12-14
  • Synthesis of organo-soluble metallophthalocyanines bearing electron-withdrawing substituents
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2001-12-31
    Muriel Sanchez, Eric Fache, Didier Bonnet, Bernard Meunier

    The syntheses of organo-soluble metallophthalocyanines having sulfo- and sulfonamido- electron-withdrawing substituents are reported. The simple cation exchange of the readily available tetrasodium salt of metallo-sulfophthalocyanines 1 (M = Ni, Co, Fe, Cr) by alkylammonium salts afforded the sulfophthalocyanines 2 and 3 in good yields. Complexes 2 featuring two long C18 alkyl chains are only soluble in organic solvents while tetrabutylammonium counter ions exhibit a dual solubility in both organic solvents and water for compounds 3. The tetrasulfonamidophthalocyanine complexes 5–7 with four C8, four C18 or eight C8 alkyl chains have been obtained after chlorination of the sulfophthalocyanines 1 leading to the chlorosulfonyl derivatives 4, followed by reaction with various substituted amines. The synthesis of the chromium precursors with tetrasulfo and tetrachlorosulfonyl substituents is also described. Copyright © 2001 John Wiley & Sons, Ltd.

    更新日期:2017-12-14
  • Interactions of tetracationic mercury(II), cadmium(II) and lead(II) porphyrins with DNA and their effects on DNA cleavage
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2001-12-31
    Elvis Nyarko, Masaaki Tabata

    The effects of tetrakis(1-methylpyridinium-4-yl)porphyrinatomercury(II) [Hg(TMPyP)]4+ (6) along with [Pb(TMPyP)]4+ (7), [Cd(TMPyP)]4+ (8), and [H2(TMPyP)]4+ (1) (free base porphyrin) on DNA cleavage by Haemophilus aegyptius (HaeIII) have been studied using gel electrophoresis, UV-vis absorption spectroscopy, and circular dichroism (CD) spectroscopy. The gel electrophoresis results indicate that in the absence of 6, HaeIII restriction enzyme could not cleave plasmid DNA at a low concentration of 0.2 units µl−1 after 1 h incubation at 37 °C. However, DNA cleavage occurred in the presence of 6 at the concentrations of 1.0 × 10−6 and 1.0 × 10−7 M and 0.2 units µl−1 of HaeIII under the same conditions. In addition, acceleration of DNA cleavage occurred at a higher concentration of HaeIII (0.4 units µl−1) in the presence of a wider concentration range of 6 from 1.0 × 10−5 to 1.0 × 10−7 M. 8, 7, and 1 could not enhance DNA cleavage in the presence of HaeIII (0.2 units µl−1). However, when the concentration of HaeIII was increased to 0.4 units µl−1, only 8 inhibited DNA cleavage by HaeIII at higher concentrations (1.0 × 10−5–10−6 M) whereas 6, 7, and 1 did not. The UV-vis and CD spectroscopic results indicate that these porphyrins interact differently with DNA based on their binding modes. 6 enhanced DNA cleavage due to the synergistic effect of the Hg2+ ions and the free base porphyrin 1 that dissociated from the mercury(II) porphyrin complex upon binding to DNA which resulted in the enhanced transformation of the DNA conformation from the original B-form to a Z-like conformation, while 8 inhibited HaeIII activity at higher concentrations and 7 and 1 neither enhanced nor inhibited DNA cleavage. A mechanism for this phenomenon is suggested. Copyright © 2001 John Wiley & Sons, Ltd.

    更新日期:2017-12-14
  • Tetrakis(selenodiazole)porphyrazines. 2: Metal complexes with Mn(II), Co(II), Ni(II), and Zn(II)
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2001-12-31
    Silvia Angeloni, Elvira M. Bauer, Claudio Ercolani, Irina A. Popkova, Pavel A. Stuzhin

    The present report describes two series of new porphyrazine macrocycles derived from tetrakis(selenodiazole)porphyrazine, TSeDPzH2, having the formulae [TSeDPzM](CH3COOH)(H2O)x M = Mn(II), Co(II), Ni(II), Zn(II); x = 4–6) and [TSeDPzM(py)](CH3COOH)(H2O)x (M = Mn(II), Co(II), Ni(II); x = 1–5), obtained by reaction of the free ligand with the appropriate metal acetate in dimethyl (DMSO), and, respectively, pyridine. All the species isolated are stable-to-air substantially amorphous materials, almost completely insoluble in the usual organic solvents and N-donors (pyridine etc.), and only slightly soluble in CF3COOH or 96% H2SO4. The complexes have been investigated by IR, Raman, and UV-vis spectra, and magnetic susceptibility measurements. Their properties in terms of electronic structure and reactivity towards N-bases are discussed in comparison with their S-containing analogs and the class of the structurally similar metal phthalocyanines. Copyright © 2001 John Wiley & Sons, Ltd.

    更新日期:2017-12-14
  • The nature of the bonding between metalloporphyrins [Fe(II), Co(II), Mn(II)] and oxygen species (·O 2·, H2+O·/HO·, HOO·, ·O·)
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2001-12-31
    Donald T. Sawyer

    The interaction of reduced transition-metal porphyrins [e.g. PMn(II), PFe(II), PCo(II)] with oxygen species (·O·, H2+O·/HO·, HOO·, ·O·) involves radical/radical coupling to form covalent bonds. Coordinately unsaturated iron(II) porphyrins form two sigma bonds with ·O·(−ΔGBF = 1–6 kcal mol−1) via two of the four unpaired d-electrons of the iron center. The hydroxyl radical couples with an unpaired electron of the PM(II) porphyrins to form a single covalent bond . The bond energies (−ΔGBF) for and are 65 ± 4 and 58 kcal mol−1, respectively. Under neutral conditions the uncharged species [(Cl8TPP)MnIII–OH, (Cl8TPP)FeIII–OH, (Cl8TPP)CoIII–OH] have bond-formation energies (−ΔGBF) of 70 ± 4, 63, and 61 kcal mol−1, respectively. In acetonitrile solutions atomic oxygen (·O·; derived from ozone, O3) couples with (Cl8TPP)MnIII[ClO4], (Cl8TPP)MnII, (Cl8TPP)FeIII[ClO4], and (Cl8TPP)FeII to form (Cl8TPP+)MnVO (−ΔGBF = 59 ± 4 kcal mol−1), (Cl8TPP)MnIVO (85 kcal mol−1), (Cl8TPP+·)FeIVO (68 kcal mol−1; model for compound I of horseradish peroxidase), and (Cl8TPP)FeIVO (78 kcal mol−1; model for compound II of horseradish peroxidase). The weakly bonded species [(Cl8TPP+)MnVO and (Cl8TPP+·)FeIVO] epoxidize olefins with near-stoichiometric efficiency; the other two species are essentially unreactive with olefins. Copyright © 2001 John Wiley & Sons, Ltd.

    更新日期:2017-12-14
  • Susanna J. Shaw, Sakthitharan Shanmugathasan, Oliver J. Clarke, Ross W. Boyle, Alan G. Osborne and Christine Edwards, ‘A 13C NMR spectral examination of α- and β-carbon signal peak heights in some disubstituted arylporphyrins’.Journal of Porphyrins and Phthalocyanines5(7)2001, 575‒581
    J. Porphyr. Phthalocyanines (IF 1.043) Pub Date : 2002-01-03
    Susanna J. Shaw, Sakthitharan Shanmugathasan, Oliver J. Clarke, Ross W. Boyle, Alan G. Osborne, Christine Edwards

    The original article to which this Erratum refers was published in The Journal of Porphyrins and Phthalocyanines 5(7) 2001, 575–581 In the above paper the following was omitted: Acknowledgements: The authors wish to thank the Wellcome Trust (0497047) for financial support, and EPSRC Mass Spectrometry Service Swansea for analyses. SJS also thanks EPSRC for a studentship.

    更新日期:2017-12-14
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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