Expanded Porphyrins Research Articles

Synthesis and Characterization of New Non-aromatic Texaphyrin-type Expanded Porphyrins

The synthesis and X-ray diffraction-based characterization of a texaphyrin-type non-aromatic expanded porphyrin, 13,18,22,27-tetraethyl-14,17,23,26-tetramethyl-20-p-nitrophenyl-3,10,28,29,30,31-hexaazahexacyclo[23.2.1.04,9.112,15.116,19.121,24]untriaconta-2, 4, 5, 7, 10,12,14,16,18,-20,22,24(30),25,27-tetradecaene (1), is reported. This Schiff base macrocycle was prepared in good yield via the 1:1 HCl -catalyzed condensation of a tetrapyrrole dialdehyde precursor, (di(5-formyl-4,4'-diethyl-3,3'-dimethyl-2,2'-bipyrrole)-p-nitrophenylmethine), with 1,2-phenylenediamine. Compound 1 was assigned as being a 26 π-electron non-aromatic benzannulene on the basis of both proton NMR and single-crystal X-ray diffraction analyses. The latter studies, in particular, revealed a non-planar macrocyclic structure co-crystallized with a molecule of water. By varying either the diamine used in the cyclization step and/or the substituent in the meso-position of the tetrapyrrolic precursor, a range of other systems analogous to 1 could be obtained. The resulting systems were found to present good stability both in the solid state and in solution.

Molecular Receptors Based on Expanded Porphyrins

Studies on the design and synthesis of receptor molecules capable of selectively binding and transporting substrates (neutral, anionic and cationic) is currently being pursued to develop artificial membranes permeable to the bound species. Expanded porphyrin systems by virtue of increased cavity size and aromatic nature are capable of binding a variety of substrates depending on the nature of the porphyrin and the cavity size. Recently there are a number of reports on the use of expanded porphyrins as molecular receptors for various substrates. Specifically, expanded porphyrins such as sapphyrins and rubyrins in their protonated form bind a variety of anionic and neutral substrates and it has been shown that they act as carriers for transporting different ionic and neutral species. Additionally, expanded porphyrins find their application as MRI contrasting agents and as sensitizers for photodynamic therapy. In this review, an attempt has been made to discuss molecular receptor properties in the solid and solution phases of two expanded porphyrins, sapphyrin and rubyrin which are 22π and 26π electron systems respectively. Furthermore, the synthesis, binding and transport properties of core modified expanded porphyrin systems are also highlighted.

ChemInform Abstract: Synthesis of meso‐Substituted Core Modified Expanded Porphyrins; Effect of Acid Catalysts on the Cyclization.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Ground and Excited State Dynamics of Core-modified Normal and Expanded Porphyrins

Singlet and triplet excited state data on two new core-modified expanded porphyrins and their protonated derivatives are reported. Absorption spectral studies indicate a gradual red shift of the absorption bands upon sulfur substitution into the core. The singlet lifetimes for expanded S3-sapphyrin and S4-rubyrin decrease steadily relative to STPPH and S2TPP owing to a higher rate of intersystem crossing. Furthermore, the protonated derivatives of S3-sapphyrin and S4-rubyrin encapsulate fluoride ions into their cavities with binding constants of 807 and 48 M−1respectively. However, the triplet lifetime for S3-sapphyrin is longer (58.80 μs) than for normal thiaporphyrins (STPPH, 37.45 μs; S2TPP , 20.96 μs), suggesting that it could be very well suited for photosensitizing triplet oxygen.

Potentiometric Responses of Expanded Porphyrin Incorporated Liquid Membrane Electrodes toward a Series of Inorganic and Organic Anions

The potentiometric responses of liquid membrane electrodes based on expanded porphyrins such as sapphyrin, rubyrin and triphenylrosarin, toward a series of organic carboxylates and inorganic anions were investigated. pH titration of these expanded porphyrin based electrodes with and without a guest anion in the sample solution showed that protonation of the expanded porphyrins at the surface of the electrode membrane is a prerequisite for accommodating the guest anions and yielding their potential responses. The electrodes strongly responded to benzoates, but rather less to inorganic anions and saturated aliphatic organic carboxylates. The selectivity sequences for the sapphyrin based electrode were found in some cases to deviate from the Hofmeister series; fluoride preference over chloride and bromide is particularly noted. Interesting responses were observed by the electrodes for discriminating geometrical isomers: hydrogenmaleate over hydrogenfumarate, and positional isomers: phthalate over iso- and terephthalate and trichloroacetate over di- and mono-chloroacetates.

Expanded Porphyrins and Their Heterologs.

Expanded Porphyrins and Their Heterologs.

Nonlinear optical Properties of Pentaazadentate Expanded Porphyrins and Application in Optical Limiting

AbstractNonlinear optical properties of asymmetric pentaazadentate expanded porphyrin metal complexes are investigated. The transmittance dependence of the target compounds on the incident laser intensity generates different nonlinear optical effects in the excited states. The reverse saturable absorption at 532 nm in the ns pulses and the saturable absorption for the pspulses at high fluences are observed in solutions. The nonlinear refractive indices n2 aremeasured by the Z-scan technique. The optical limiting based on the RSA and transverse refraction are demonstrated for ns and continuous laser. An optical limiter based on the RSA and self-refraction is performed, in which the limitating threshold and amplitude of output energy are reduced.

ChemInform Abstract: Expanded Porphyrins. Receptors for Cationic, Anionic, and Neutral Substrates

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Hexaalkyl Terpyrrole: A New Building Block for the Preparation of Expanded Porphyrins

AbstractA new, general synthesis of the first β‐substituted tetra‐ and hexaalkyl terpyrroles is described. Also described are two new classes of expanded porphyrins derived from the hexaalkyl terpyrrole. The key step in the terpyrrole formation is the copper(II)‐mediated oxidative coupling of the LDA‐derived enolates of α‐keto pyrroles. The first new expanded porphyrin reported here, the so‐called “orangarin”, contains five pyrrolic subunits and two bridging carbon atoms, and is formally a 20π‐electron nonaromatic macrocycle. The second new class of expanded porphyrins, the “amethyrins”, are 24π‐electron nonaromatic macrocycles containing six pyrrole units. Both of these new macrocycles, as well as one of the new terpyrrolic precursors have been structurally characterized by single crystal X‐ray diffraction analysis.

Sequence-Specific Photocleavage of DNA by an Expanded Porphyrin with Irradiation above 700 nm

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSequence-Specific Photocleavage of DNA by an Expanded Porphyrin with Irradiation above 700 nmDarren Magda, Meredith Wright, Richard A. Miller, Jonathan L. Sessler, and Petra I. SansomCite this: J. Am. Chem. Soc. 1995, 117, 12, 3629–3630Publication Date (Print):March 1, 1995Publication History Published online1 May 2002Published inissue 1 March 1995https://doi.org/10.1021/ja00117a039RIGHTS & PERMISSIONSArticle Views221Altmetric-Citations66LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-AlertsSupporting Info (3)»Supporting Information Supporting Information Get e-Alerts

ChemInform Abstract: meso‐Phenyl Substituted Porphocyanines: A New Class of Functionalized Expanded Porphyrins.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of Binuclear Copper (II) Complexes with Expanded Porphyrins

The synthesis and characterization of some new binuclear copper (II) complexes, based on the use of large, pyrole-containing macrocycles, the so called expanded porphyrins, [Cu2(macrocycle)]+4 is described. Electron Spin Resonance (ESR) studies indicate a weak half-field line, which is characteristic of the Cu(II)-Cu(II) dimer, is observed at about 1600G. The observation of this band strongly suggests that the hyperfine structure arises from a spin triplet species.

Fluorometric Determination of Trace Amounts of Fluoride Ion Using an Expanded Porphyrin

A highly selective and sensitive method of fluorometry is described for determination of the fluoride ion at the parts per billion level via the ion-pair complex formation of the fluoride ion with an expanded prophyrin [2,23-diethyl-8,17-bis(2-ethoxycarbonylethyl)-3,7,12,13,18,22-hexamethylsapphyrin (H3sap)]. The ion-pair complex gives out an enhanced fluorescence intensity at 680 nm on excitation at 450 nm. Since the present method is based on a direct reaction of the fluoride ion with the sappyrin, a 200-fold amount of the aluminum (III) ion [10−4M (M = mol dm−3)] and a 2000-fold amount of the iron(III) ion (10−3M) over the fluoride ion did not interfere with determination of the fluoride ion at concentrations as low as 5 × 10−7M in the presence of 1,2-diaminocyclohexane-N,N,N′,N′-teraacetic acid. The proposed method was applied to determination of the fluoride ion in various water samples (tap water, river water, rain water, underground water, and hot spring water) and satisfactory results were obtained.

ChemInform Abstract: A Nonaromatic Expanded Porphyrin Derived from Anthracene. A Macrocycle Which Unexpectedly Binds Anions.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A Nonaromatic Expanded Porphyrin Derived from Anthracene—A Macrocycle which Unexpectedly Binds Anions

A Nonaromatic Expanded Porphyrin Derived from Anthracene—A Macrocycle which Unexpectedly Binds Anions

ChemInform Abstract: 113Cd Shielding Tensors of the Cadmium Complex of Texaphyrin, a Novel Expanded Porphyrin, and Its Pyridine and Benzimidazole Adducts

The cadmium complex of an expanded five-coordinate porphyrin known as texaphyrin and its complexes with pyridine and benzimidazole have been investigated by solution- and solid-state {sup 113}Cd NMR spectroscopy, and the results are reported. The principle shielding tensor elements were determined for each complex and are discussed in terms of reported crystal studies of Cd-texaphyrin and in comparison to cadmium complexes with other porphyrin and similar macrocycle ligands. 18 refs., 5 figs., 1 tab.

ChemInform Abstract: A Water‐Stable Gadolinium(III) Complex Derived from a New Pentadentate “Expanded Porphyrin” Ligand.

AbstractThe general lanthanoid‐binding properties of new monoanionic porphyrin‐like ligands are explored.

ChemInform Abstract: Binding of Pyridine and Benzimidazole to a Cadmium “Expanded Porphyrin”: Solution and X‐Ray Structural Studies.

AbstractThe pentagonal‐pyramidal complex (III), derived from a novel 22‐π‐electron pentadentate "expanded porphyrin" ligand, crystallizes in P1 with Z=2.

ChemInform Abstract: An “Expanded Porphyrin”: The Synthesis and Structure of a New Aromatic Pentadentate Ligand.

AbstractThe "expanded porphyrin" ligand of the Cd complex (I) is prepared by direct acid‐catalyzed condensation of o‐phenylenediamine and the corresponding bis(formylpyrrolylmethyl)pyrrole and subsequent reduction.

Expanded Porphyrins: The Synthesis and Metal Binding Properties of Novel Tripyrrane-Containing Macrocycles

Abstract Novel tripyrrane macrocycles have been prepared by the Schiff base condensation of 2,5-bis-(3-ethyl-5-formyl-4-methyl-pyrrol-2-ylmethyl)-3,4-diethylpyrrole and simple diamines. The structurally characterized macrocycle 1 forms 1:1 complexes with both Rh(I) and Zn(II) cations in which the metal is coordinated only to the imine nitrogens. In the presence of Cd(II) and oxygen, however, compound 1 is oxidized to the aromatic pentadentate ‘expanded porphyrin’ macrocycle 5, into which the metal cation is fully complexed.