Aromatic and Nonaromatic Pyriporphyrins

Lash, Timothy D.; Pokharel, Komal; Serling, Jill M; Yant, Valerie R.; Ferrence, Gregory M.

doi:10.1021/ol071052x

Cited by 69 publications

(92 citation statements)

References 30 publications

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“…82 X-ray crystallography confirmed that the complexes retained quinoidal structures and demonstrated that they exist in the zwitterionic forms shown in Scheme 59. 85,87 Lithium-halogen exchange with 3,5dibromopyridine, followed by reaction with aromatic aldehydes gave dicarbinols 150 (Scheme 61). 83 The proton NMR spectrum of 143 at room temperature showed the internal CH and NH protons at 1.89 and 4.67 ppm, and was consistent with a symmetical structure possessing a weak diatropic ring current.…”

Section: Aza-analogues Of Benziporphyrinsmentioning

confidence: 99%

Benziporphyrins, a unique platform for exploring the aromatic characteristics of porphyrinoid systems

2015

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Benziporphyrins were first discovered over 20 years ago. Although initially they were considered to be a chemical curiosity, a wide range of benzene-containing porphyrinoid systems are now known that exhibit intriguing spectroscopic, structural and chemical properties. These systems can often generate stable organometallic derivatives, and have been shown to have applications in the development of chemical sensors and in molecular recognition studies. The characteristics of these porphyrinoid macrocycles vary from nonaromatic to highly aromatic systems, and in a few cases antiaromatic structures are formed. The variations in aromatic character are insightful and provide a deeper understanding of aromaticity and conjugation in porphyrinoid structures. In this review, the synthesis and properties of benziporphyrinoid systems is presented with a particular emphasis on the variations in aromatic characteristics.

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Section: Aza-analogues Of Benziporphyrinsmentioning

confidence: 99%

Benziporphyrins, a unique platform for exploring the aromatic characteristics of porphyrinoid systems

2015

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“…[9–12] However, the benzene and pyridine moieties, respectively, are not fully conjugated into a porphyrin-like aromatic system. In contrast, oxypyriporphyrin 3 contains a porphyrin-like π-aromatic system incorporating the pyridone moiety.…”

Section: Introductionmentioning

confidence: 99%

Stepwise Conversion of Two Pyrrole Moieties of Octaethylporphyrin to Pyridin‐3‐ones: Synthesis, Mass Spectral, and Photophysical Properties of Mono and Bis(oxypyri)porphyrins

Ryppa

Niedzwiedzki

Morozowich

et al. 2009

Chemistry A European J

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Free base octaethylporphyrin (OEP) was converted, in two steps (β,β′-dihydroxylation, oxidative diol cleavage with concomitant aldol condensation), to the corresponding oxypyriporphyrin. This conversion was previously described to be only applicable to the Ni(II) complex of OEP. Modified diol cleavage conditions made this reaction sequence now applicable to free base OEP. The single crystal structure of the resulting free base oxypyriporphyrin was determined, proving its near-perfect planarity. The reaction sequence can also be applied to oxypyriporphyrin itself, generating the unprecedented bacteriochlorin-type bis-oxypyriporphyrin as two separable isomers. The ground state (UV/Vis and fluorescence) and excited state (transient triplet-triplet absorption, triplet lifetimes, and triplet EPR) photophysical properties of all chromophores are described and contrasted against OEP, chlorins, and oxochlorins. The pyridone-modified porphyrins possess unique spectroscopic signatures that distinguish them from regular porphyrins or chlorins. The presence of the pyridone moiety alters the ESI+ collision-induced fragmentation properties of these oxypyriporphyrins only to a minor degree when compared to those of OEP or chlorins, attesting to their stability.

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“…[25,38,39] Azuliporphyrins 6 show comparable diatropic character to the cross-conjugated NCPs 21, in both cases showing the internal CH resonances in proton NMR spectra near 3 ppm, although this property is greatly enhanced upon protonation. [25,39] Other systems that have been prepared using the '3 + 1' approach include N-confused pyriporphyrin 24, [40] oxynaphthiporphyrins 25 [41] and tropiporphyrins 8. [27,42] Further structural diversity can be introduced when modified tripyrrane structures are utilized in these syntheses (Scheme 2).…”

Section: Synthetic Methodologiesmentioning

confidence: 99%

“…[40] In 42b and 42c, a carbon atom is present in the macrocyclic core and these systems can be considered to be azabenziporphyrins. …”

Section: Synthetic Methodologiesmentioning

confidence: 99%

“…[57,58] An N-confused pyriporphyrin 87, which can be considered to be a 2-azabenziporphyrin, was also shown to form a palladium(II) complex 88. [40] Oxybenziporphyrin 4 was shown to form an anionic palladium(II) complex 89 that retains the ketounit, [74,75] although the related platinum(II) complex appears to favor the phenolic form 90. [71] Reaction of oxybenziporphyrins 4 with silver(I) acetate gave the silver(III) derivatives 91 in high yields.…”

Section: Td Lashmentioning

confidence: 99%

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