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Hewage N, Damunupola D, Zeller M, Brückner C. Direct Oxidations of meso-Tetrakis(pentafluorophenyl)porphyrin: Porphotrilactones and Entry into a Nonbiological Porphyrin Degradation Pathway. J Org Chem 2024; 89:6584-6589. [PMID: 38652047 DOI: 10.1021/acs.joc.4c00283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
The direct oxidations of meso-tetrakis(pentafluorophenyl)porphyrin using cetyltrimethylammonium permanganate (CTAP), RuCl3/Oxone/base or Ag+/oxalic acid each generate distinctive product mixtures that may contain, inter alia, porpho-mono-, di-, and trilactones. The CTAP and RuCl3/Oxone/base oxidations also generate a unique open chain tripyrrin derived from the degradation of a porpholactone oxazolone moiety. Thus, its formation and structure are distinctly different from all biological or nearly all other nonbiological biliverdin-like linear porphyrinoid degradation products that are derived from ring cleavages between the pyrrolic building blocks.
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Affiliation(s)
- Nisansala Hewage
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States
| | - Dinusha Damunupola
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States
| | - Matthias Zeller
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, United States
| | - Christian Brückner
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States
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Badri Z, Nourigheimasi F, Foroutan-Nejad C. Tetraquinolines; four linked quinoline units or porphyrinoids. Org Biomol Chem 2024; 22:2284-2291. [PMID: 38407320 DOI: 10.1039/d3ob01616a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Tetraquinolines (TEQs) have been recently synthesized and proposed to be a new member of the porphyrinoid family with highly distorted, nonplanar, geometries. In this contribution by studying several molecules, closely related to TEQs, we have suggested that the origin of the nonplanarity of TEQs and their counterparts is a combination of steric strain and the propensity of the molecules to avoid antiaromaticity. The tendency of TEQs to coordinate with doubly charged metal ions can be interpreted in terms of their transition from potential antiaromaticity to nonaromaticity. Even metal-coordinated TEQs do not sustain diatropic ring currents. Although full planarization is not possible because of steric strain, doubly oxidized TEQs and their counterparts sustain moderate global diatropic ring currents and partially planarize. The nature of current density in the molecules is studied in the light of Steiner-Fowler selection rules.
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Affiliation(s)
- Zahra Badri
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Farnoush Nourigheimasi
- Department of Chemistry, State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Cina Foroutan-Nejad
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
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Bhattacharya S, Nevonen DE, Auty AJ, Graf A, Appleby M, Chaudhri N, Chekulaev D, Brückner C, Chauvet AAP, Nemykin VN. Photophysical Exploration of Two Isomers of Octaethyltrioxopyrrocorphin. J Phys Chem A 2023; 127:7694-7706. [PMID: 37690121 DOI: 10.1021/acs.jpca.3c03184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
The introduction of three β-oxosubstituents to octaethylporphyrin by means of an oxidation/rearrangement reaction generates the trioxopyrrocorphin chromophore. Pyrrocorphins (hexahydroporphyrins) are generally nonaromatic, but we recently demonstrated trioxopyrrocorphins to possess considerable aromatic character. This contribution explores the photophysical characteristics of these unusual chromophores. In agreement with density functional theory modeling, the UV-vis and magnetic circular dichroism spectra of the two─out of the four possible─triketone regioisomers investigated conform to the Gouterman model of porphyrinoid optical spectra, in alignment with their aromaticity. Their excited-state dynamics shed further light on the degree to which β-oxo substitutions tune the photophysical properties of porphyrinoids. Introduction of β-oxo functionalities increases the rate and yield of intersystem crossing and shortens the triplet state lifetime. Unexpectedly, the singlet oxygen generation yield of both pyrrocorphins remains relatively high, with modes of distortion from planarity likely enhancing triplet energy transfer. This work thus expands our understanding of a rare class of porphyrinoids and further characterizes them as sustaining aromatic porphyrinic π-systems. Our findings suggest triple β-oxo substitution as a viable route toward the development of novel, high-singlet oxygen yield porphyrinic photosensitizers.
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Affiliation(s)
- Sayantan Bhattacharya
- Department of Chemistry, University of Sheffield, Dainton Building, Sheffield S3 7HF, U.K
| | - Dustin E Nevonen
- Department of Chemistry, University of Tennessee, 1420 Circle Dr., Knoxville, Tennessee 37996-1600, United States
| | - Alexander J Auty
- Department of Chemistry, University of Sheffield, Dainton Building, Sheffield S3 7HF, U.K
| | - Arthur Graf
- Department of Chemistry, University of Sheffield, Dainton Building, Sheffield S3 7HF, U.K
| | - Martin Appleby
- Department of Chemistry, University of Sheffield, Dainton Building, Sheffield S3 7HF, U.K
| | - Nivedita Chaudhri
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States
| | - Dimitri Chekulaev
- Department of Chemistry, University of Sheffield, Dainton Building, Sheffield S3 7HF, U.K
| | - Christian Brückner
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States
| | - Adrien A P Chauvet
- Department of Chemistry, University of Sheffield, Dainton Building, Sheffield S3 7HF, U.K
| | - Victor N Nemykin
- Department of Chemistry, University of Tennessee, 1420 Circle Dr., Knoxville, Tennessee 37996-1600, United States
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