The synthesis of some substituted tetraarylporphyrins
TL;DR: In this article, the synthesis of six unsymmetrically substituted tetraaryl porphyrins is reported, and the proton nmr spectra of these porphyrins are presented.
About: This article is published in Journal of Heterocyclic Chemistry.The article was published on 1975-04-01. It has received 276 citations till now. The article focuses on the topics: Proton NMR.
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TL;DR: The history of the first generation PDT agent hematoporphyrin derivative is described in detail in this article, where the optical spectra of porphyrins and chlorins are analyzed.
916 citations
TL;DR: This chapter briefly surveys the concept of multivalency involved in carbohydrate–protein interactions and discusses in regard to recent steps undertaken in glycobiology toward identification of lead candidates using microarrays and modern analytical tools.
Abstract: From the authors' opinion, this chapter constitutes a modest extension of the seminal and inspiring contribution of Stowell and Lee on neoglycoconjugates published in this series [C P Stowell and Y C Lee, Adv Carbohydr Chem Biochem, 37 (1980) 225-281] The outstanding progresses achieved since then in the field of the "glycoside cluster effect" has witnessed considerable creativity in the design and synthetic strategies toward a vast array of novel carbohydrate structures and reflects the dynamic activity in the field even since the recent chapter by the Nicotra group in this series [F Nicotra, L Cipolla, F Peri, B La Ferla, and C Radaelli, Adv Carbohydr Chem Biochem, 61 (2007) 353-398] Beyond the more classical neoglycoproteins and glycopolymers (not covered in this work) a wide range of unprecedented and often artistically beautiful multivalent and monodisperse nanostructures, termed glycodendrimers for the first time in 1993, has been created This chapter briefly surveys the concept of multivalency involved in carbohydrate-protein interactions The topic is also discussed in regard to recent steps undertaken in glycobiology toward identification of lead candidates using microarrays and modern analytical tools A systematic description of glycocluster and glycodendrimer synthesis follows, starting from the simplest architectures and ending in the most complex ones Presentation of multivalent glycostructures of intermediate size and comprising, calix[n]arene, porphyrin, cyclodextrin, peptide, and carbohydrate scaffolds, has also been intercalated to better appreciate the growing synthetic complexity involved A subsection describing novel all-carbon-based glycoconjugates such as fullerenes and carbon nanotubes is inserted, followed by a promising strategy involving dendrons self-assembling around metal chelates The chapter then ends with those glycodendrimers that have been prepared using commercially available dendrimers possessing varied functionalities, or systematically synthesized using either divergent or convergent strategies
294 citations
Cites background from "The synthesis of some substituted t..."
...Synthesis of glucosylated porphyrins bearing cationic head-groups.(153) SYNTHESIS OF MULTIVALENT NEOGLYCOCONJUGATES 215...
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...An elegant synthesis of a monomeric porphyrin intermediate bearing one pyridyl and three glycosyl units, precursor of cationic dimers, has also been described (Scheme 18).(153) Thus pyrrole, p-formylphenyl 2,3,4,6-tetra-O-acetyl-b-D-...
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TL;DR: This work has developed methodology that avoids statistical reactions, employs minimal chromatography, and affords up to gram quantities of regioisomerically pure porphyrins bearing predesignated patterns of up to four different meso substituents.
Abstract: Porphyrins bearing specific patterns of substituents are crucial building blocks in biomimetic and materials chemistry. We have developed methodology that avoids statistical reactions, employs minimal chromatography, and affords up to gram quantities of regioisomerically pure porphyrins bearing predesignated patterns of up to four different meso substituents. The methodology is based upon the availability of multigram quantities of dipyrromethanes. A procedure for the diacylation of dipyrromethanes using EtMgBr and an acid chloride has been refined. A new procedure for the preparation of unsymmetrical diacyl dipyrromethanes has been developed that involves (1) monoacylation with EtMgBr and a pyridyl benzothioate followed by (2) introduction of the second acyl unit upon reaction with EtMgBr and an acid chloride. The scope of these acylation methods has been examined by preparing multigram quantities of diacyl dipyrromethanes bearing a variety of substituents. Reduction of the diacyl dipyrromethane to the c...
250 citations
TL;DR: In this paper, the role of the coordination bond in polyporphyrin architecture is discussed and a review of the role and role of coordination bonds in the construction of polymorphs is presented.
228 citations
TL;DR: In this paper, a set of porphyrin building blocks is developed for the construction of light-harvesting model compounds and related molecular photonic devices, which are facially encumbered to enhance solubility in organic solvents, are employed in a defined metalation state (free base (Fb) or zinc chelate), and bear peripheral functional groups such as iodo or ethyne for joining the porphrin via covalent bonds.
Abstract: A set of porphyrin building blocks has been developed for the construction of light-harvesting model compounds and related molecular photonic devices. The porphyrins are facially encumbered to enhance solubility in organic solvents, are employed in a defined metalation state (free base (Fb) or zinc chelate), and bear peripheral functional groups such as iodo or ethyne for joining the porphyrins via covalent bonds. The coupling of an iodophenylporphyrin and an ethynylphenylporphyrin via mild Pd-mediated reactions (2−4 mM of each porphyrin in toluene/triethylamine (5:1) with Pd2(dba)3 and AsPh3 at 35 °C for 2 h) yields the corresponding diphenylethyne-linked multiporphyrin array in 70−80% yield. The arrays are easily purified by a sequence of flash silica chromatography, preparative size exclusion chromatography, and gravity elution silica chromatography. The diphenylethyne linkers give a center-to-center separation of the porphyrins of ∼20 A. Model light-harvesting compounds are easily prepared using Zn an...
228 citations
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TL;DR: It is concluded that the ground-state symmetries of ZnTPP+ and MgOEP+ are, respectively, 2AZu and 2A1u of the D4h point group, and a radical may occupy either of two close-lying ground states.
Abstract: Zinc tetraphenylporphyrin (ZnTPP) and magnesium octaethylporphyrin (MgOEP) undergo reversible oneand two-electron oxidations. Removal of the first electron by controlled potential electrolysis or by oxidation with xenon difluoride or bromine results in cation radicals whose esr spectra clearly indicate electron abstraction from the porphyrin ring. The observed hyperfine structure is assigned, with the help of deuterium labeling, to interaction of the unpaired electron with the meso protons of MgOEP+ and with the protons on the phenyl groups of ZnTPP+. Electronic absorption spectra of the radicals, dications, and of a dimer of MgOEP+ which exists at low temperatures are presented. The results of an SCF-MO study are compared with the experimental esr and optical data. These calculations suggest that a radical may occupy either of two close-lying ground states. We conclude that the ground-state symmetries of ZnTPP+ and MgOEP+ are, respectively, 2AZu and 2A1u of the D4h point group. C steps in photosynthetic and metabolic processes involve metalloporphyrin redox properties. Prior studies of heme function have stressed the redox characteristics of the central metal; s, 4 in contradistinction, primary photosynthetic events involving (I) Aspects of this work were previously presented: (a) J. Fajer. D. C. Borg. D. Dolphin. and R. H. Felton. Abstracts. 157th National Meeting of the American Chemical Society. Minneapolis, Minn .• April 1969. p 130; (b) R. H. Felton. D. Dolphin. D. C. Borg. and J. Fajer. J. A mer. Chern. Soc .• 91. 196 (1969). (2) (a) Department of Applied Science, Brookhaven National Laboratory; (b) Medical Department. Brookhaven ::-.lational Laboratory; (cl Harvard University; (d) Georgia Institute of Technology. (3) J. E. Falk, \"Porphyrins and Metalloporphyrins,\" Elsevier Publishing Co., New York, N. Y., 1964. (4) B. Chance, R. W. Estabrook. and T. Yonetani, Ed .• \"Hemes and Hemoproteins.\" Academic Press, New York, N. Y .• 1966. chlorophyll appear to depend upon ring redox properties.o· 6 A striking feature of the porphyrin ring is its ability to undergo facile reduction and oxidation. Reductions of chlorophylF and metalloporphyrins,8 dissolved in apr otic solvents. have been accomplished byelectrochemical and chemical techniques, and the results (5) B. Kok, Biochirn. Biophys. Acta, 48. 527 (1961). (6) J. Weikard, A. Muller. and H. T. Witt. Z. Natur/orsch .• 18b. 139 (1963). (7) R. H. Felton, G. W. Sherman, and H. Linschitz. Nature, 203, 631 (1964). (8) G. L. Closs and L. E. Closs. J. Arner. Chem. Soc., 85, 818 (1963); N. Hush and J. Dodd. J. Chern. Soc .• 4601 (1964); D. Clack and N. Hush. J. Amer. Chern. Soc., 87, 4238 (1965); R. H. Felton and H. Linschitz, ibid., 88, 1113 (1966). Fajer, Borg, Forman, Dolphin, Felton / Dications of Metalloporphyrins
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