Metalation of Expanded Porphyrins: A Chemical Trigger Used To Produce Molecular Twisting and Möbius Aromaticity

Tanaka, Yasuo; Saito, Shohei; Mori, Shigeki; Aratani, Naoki; Shinokubo, Hiroshi; Shibata, Naoki; Higuchi, Yoshiki; Yoon, Zin Seok; Kim, Kil Suk; Noh, Su Bum; Park, Jong Kang; Kim, Dongho; Osuka, Atsuhiro

doi:10.1002/anie.200704407

Cited by 312 publications

(240 citation statements)

References 30 publications

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“…[39,47,100] Two-photon absorption crosssections have been recently found to correlate with NICS values of some porphyrinoids, and have therefore been advocated as a useful aromaticity criterion. [101][102][103] Magnetic Criteria. The importance of proton chemical shifts as an aromaticity measure was recognized in the very first NMR spectroscopic study of porphyrin derivatives.…”

Section: Aromaticity Criteriamentioning

confidence: 99%

Figure Eights, Möbius Bands, and More: Conformation and Aromaticity of Porphyrinoids

2011

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The aromatic character of porphyrins, which has significant chemical and biological consequences, can be substantially altered by judicious modifications of the parent ring system. Expansion of the macrocycle, which is achieved by introducing additional subunits, usually increases the so-called free curvature of the ring, leading to larger angular strain. This strain is reduced by a variety of conformational changes, most notably by subunit inversion and p surface twisting. The latter effect creates a particularly convenient access to Möbius aromatic molecules, whose properties, predicted over 40 years ago, are of considerable theoretical importance. The conformational processes occurring in porphyrin analogues are often coupled to other chemical phenomena, and can thus be exploited as a means of constructing functional molecular devices. In this Review, the structural chemistry of porphyrinoids is discussed in the context of their conformational dynamics and p-electron conjugation.

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Section: Aromaticity Criteriamentioning

confidence: 99%

Figure Eights, Möbius Bands, and More: Conformation and Aromaticity of Porphyrinoids

2011

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“…[132] Interessanterweise stabilisiert das ähnliche Heptaphyrin 67g-H 4 , das 2,6-Dichlorphenylsubstituenten enthält, die T1-Konformation auch in nichtpolaren Lösungsmit-teln. [103] [251] Auch ein Kupfer(II)-Komplex 71c-Cu wurde beschrieben, der eine einmalige T-förmige Koordinationsgeometrie des Kupfer(II)-Zentrums stabilisiert. [252,253] 8.…”

Section: Heptaphyrineunclassified

“…[67,100,103,238,264,265] Auch manche Heteroanaloga dieser Systeme (86, 87 und 88-H 2 ) haben die Figure-EightKonformation. [126,257] Untereinheiten.…”

Section: T1-und T2-systemeunclassified

“…Ungewöhnliche Konformere wurden im Festkörper für die meso-bperfluorierten Octaphyrine 81f-H 4 und 82f-H 6 beobachtet (Abbildung 16). [238] [103] (später wurde noch ein weiteres Produkt mit gebrochener makrocyclischen Konjugation beschrieben [270] ). In 95 e ist jedes Palladium(II)-Ion an drei Pyrrol-Stickstoffatome und ein b-Kohlenstoffatom gebunden.…”

Section: T1-und T2-systemeunclassified

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Figure‐Eight‐Strukturen, Möbius‐Bänder und mehr: Konformation und Aromatizität von Porphyrinoiden

2011

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Der aromatische Charakter von Porphyrinen, der signifikante chemische und biologische Auswirkungen hat, kann durch gezielte Modifikationen des Stammringsystems beträchtlich verändert werden. Zusätzliche Untereinheiten expandieren den Makrocyclus und erhöhen seine Ringkrümmung, was zu einer höheren Winkelspannung führt. Diese Winkelspannung kann der Ring durch eine Reihe von Konformationsänderungen wieder abbauen, insbesondere durch Invertieren von Untereinheiten und Verdrillen (twisting) der π‐Oberfläche. Letzterer Effekt bietet einen Zugang zu Möbius‐aromatischen Molekülen, deren Eigenschaften, gleichwohl vor über 40 Jahren vorausgesagt, unter theoretischen Aspekten von großer Bedeutung sind. Häufig gehen Konformationsprozesse in den Porphyrinanaloga mit anderen chemischen Phänomenen einher, sodass sie für den Aufbau von molekularen Funktionseinheiten verwendet werden können. In diesem Aufsatz wird die Strukturchemie der Porphyrinoide im Zusammenhang mit ihrer Konformationsdynamik und elektronischen π‐Konjugation diskutiert.

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“…The conformational flexibility, the number and the nature of substituents on the pyrrolic and meso positions, and the metallation of the porphyrins allow them to achieve different topologies with distinct aromaticities, magnetic, and electric properties. 4 In the last five years several Hückel and Möbius topological systems have been prepared through replacement of the solvent and protonation, [5][6][7] temperature control, 8,9 metal coordination, 10 and functional group modifications. 11 As one can see, the synthesis of aromatic systems with Möbius topology has just started and there are still a lot of aspects and applications to be analyzed.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the nonlinear optical properties for an expanded porphyrin Hückel-Möbius aromaticity switch

Torrent‐Sucarrat

Anglada²,

Luis³

2012

The Journal of Chemical Physics

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The conformational flexibility of the expanded porphyrins allows them to achieve different topologies with distinct aromaticities and nonlinear optical properties (NLOP). For instance, it is possible to switch between Möbius and Hückel topologies applying only small changes in the external conditions or in the structure of the ring. In this work, we evaluate the electronic and vibrational contributions to static and dynamic NLOP of the Hückel and Möbius conformers of A,D-di-pbenzi[28]hexaphyrin(1.1.1.1.1.1) synthesized by Latos-Grażyński and co-workers [Angew. Chem., Int. Ed. 46, 7869 (2007)]. Calculations are performed at the HF, M052X, and CAM-B3LYP levels using the 6-31G, 6-311G(d), and 6-31+G(d) basis sets. Our results conclude that M052X/6-31G and CAM-B3LYP/6-31G methods provide a correct qualitative description of the electronic and vibrational contributions for the NLOP of expanded porphyrins. The studied systems show high NLOP with large differences between the Möbius and Hückel conformations (around 1 × 10 6 a.u. forγ ). The obtained results indicate that the expanded porphyrins are promising systems to manufacture Hückel-to-Möbius topological switches.

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Metalation of Expanded Porphyrins: A Chemical Trigger Used To Produce Molecular Twisting and Möbius Aromaticity

Cited by 312 publications

References 30 publications

Figure Eights, Möbius Bands, and More: Conformation and Aromaticity of Porphyrinoids

Figure Eights, Möbius Bands, and More: Conformation and Aromaticity of Porphyrinoids

Figure‐Eight‐Strukturen, Möbius‐Bänder und mehr: Konformation und Aromatizität von Porphyrinoiden

Evaluation of the nonlinear optical properties for an expanded porphyrin Hückel-Möbius aromaticity switch

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