[40]Nonaphyrin(1.1.1.1.1.1.1.1.1) and Its Heterometallic Complexes with Palladium–Carbon Bonds

Kamimura, Yiho; Shimizu, Soji; Osuka, Atsuhiro

doi:10.1002/chem.200601304

Cited by 56 publications

(41 citation statements)

References 49 publications

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“…The smaller pocket was shown to bind Cu II or Zn II , whereas the larger pocket coordinates one or two Pd II ions through PdÀN and Pd À C bonds. [272] In the Cu Two oxidation levels have also been reported for decaphyrin(1.1.1.1.1.1.1.1.1.1), however, the substitution pattern was different in each case. 102c-H 6 , which bears trifluoromethyl substituents, is a 46-electron system and was shown to adopt an unusual, C 2 -symmeric T2 conformation in the solid state.…”

Section: Porphyrin Homologuesmentioning

confidence: 75%

“…[273] Another route, involving the use of tripyrranes, preferentially yields macrocycles containing 6, 9, and 12 pyrrolic rings. [272] Nonaphyrin(1.1.1.1.1.1.1.1.1) has two accessible oxidation levels, 99b-H 4 and 100b-H 6 , which have respectively 40-and 42-electron CPs and are mutually interconvertible by chemical oxidation and reduction. [100,272] In the solid state, the free base 100b-H 6 [100,272] Compound 99b-H 4 , investigated crystallographically in the free base form, adopts an unsymmetrical figure-eight conformation with a T2 0 topology (Figure 17).…”

Section: Porphyrin Homologuesmentioning

confidence: 99%

“…[272] Nonaphyrin(1.1.1.1.1.1.1.1.1) has two accessible oxidation levels, 99b-H 4 and 100b-H 6 , which have respectively 40-and 42-electron CPs and are mutually interconvertible by chemical oxidation and reduction. [100,272] In the solid state, the free base 100b-H 6 [100,272] Compound 99b-H 4 , investigated crystallographically in the free base form, adopts an unsymmetrical figure-eight conformation with a T2 0 topology (Figure 17). [272] The smaller of the two pockets formed by the figure-eight structure resembles a tetrapyrrolic core, whereas the larger one is reminiscent of the biconcave T0…”

Section: Porphyrin Homologuesmentioning

confidence: 99%

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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: Porphyrin Homologuesmentioning

confidence: 75%

Section: Porphyrin Homologuesmentioning

confidence: 99%

Section: Porphyrin Homologuesmentioning

confidence: 99%

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

2011

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“…[273] Ein anderer Reaktionsweg geht von Tripyrranen aus und führt zu Makrocyclen mit 6, 9 und 12 Pyrrolringen. [272] Nonaphyrin(1. [a] Repräsentative Substitutionsmuster: a partiell b-Alkyl; b meso-C 6 F 5 ; c meso-CF 3 ; d b-Alkyl-meso-Ar; e meso-Mes-meso-Anis; f meso-Ph-phenylen-(OMe) 2 ; [278] .…”

Section: Porphyrinhomologeunclassified

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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“…Separation difficulty has been somewhat mitigated by size-selective synthesis of the expanded porphyrins using a dipyrromethane and a tripyrromethane as precursors. 60,61 Use of high concentrations of the substrates led to better yields of larger expanded porphyrins. 62 These meso-aryl expanded porphyrins have proven to be attractive platforms for rich coordination chemistry, 6369 versatile aromatic compounds such as strongly Hückel aromatic 64,65,70 and antiaromatic, 64,65 Möbius aromatic 7180 and antiaromatic 81,82 species, stable organic radical species, 70,83,84 and unprecedented rearrangements triggered by transannular electronic interactions.…”

mentioning

confidence: 99%

Subporphyrins: A Legitimate Ring-Contracted Porphyrin with Versatile Electronic and Optical Properties

Osuka

Tsurumaki

Tanaka

2011

Bulletin of the Chemical Society of Japan

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119

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After a brief survey of our efforts in the development of novel porphyrinoids that include mesomeso-linked porphyrin arrays, meso-aryl expanded porphyrins, and transition-metal-catalyzed functionalizations of porphyrins, a particular focus in this account is placed on the chemistry of subporphyrins that has been explored in our group. Subporphyrin is a legitimate ring-contracted porphyrin consisting of three pyrrolic subunits domed in a C 3 symmetric bowl shape. While subporphyrins are simple and small macrocycles and possess a key position in porphyrin chemistry, they had been elusive until our first synthesis of tribenzosubporphines in 2006. Shortly after, synthetic protocols of mesoaryl-substituted subporphyrins were developed to produce various subporphyrins with versatile electronic properties that can be widely tuned by meso-aryl substituents. Raney nickel reduction was used to prepare meso-alkyl-substituted subporphyrins from meso-thienyl-substituted subporphyrins. Subchlorins and subbacteriochlorins were prepared respectively by the reduction of subporphyrins with p-tosylhydrazide and Raney nickel. While subporphyrins and subchlorins share conjugated 14³-electronic circuits, subbacteriochlorins have a rare [13]diazaannulene circuit maintained through the lone-pair electrons of the nitrogen atom. The aromaticity decreases in the order of subporphyrin > subchlorin > subbacteriochlorin, as indicated from 1 H-and 11 B NMR spectra and nuclear independent chemical shift (NICS) calculations. Despite these progresses, the chemistry of subporphyrins is still in the infant stage with many untouched aspects and further improvements in synthetic yields are highly desirable for the developments of the chemistry of subporphyrins as well as their applications in diverse fields. A Brief Survey of Our Efforts in the Exploration of Novel PorphyrinoidsIn the last three decades, we have been involved in the exploration of novel porphyrinoids with intriguing structures, electronic and optical properties, and functions. We entered porphyrin chemistry with the aim to synthesize covalently linked organic constructs that can mimic the whole excitation energy transfer and electron transfer events of the photosynthetic reaction centers within a single molecular entity. 13 In the course of these studies, we fortunately encountered new reactions and structures, which drove us to change our research style from a well-designed, goal-orientated path to a flexible discovery-searching strategy to explore novel porphyrinoids. By following the flexible research style, we have explored mesomeso-linked Zn(II) porphyrin arrays, meso-aryl expanded porphyrins, transition-metal-catalyzed porphyrin modifications, and subporphyrins. After a brief survey of the former three topics, a particular focus is placed on the chemistry of subporphyrins that are legitimate ring-contracted porphyrins. As described below, subporphyrins are a new class of functional molecules, particularly in view of their highly tunable electronic and optical properties.

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[40]Nonaphyrin(1.1.1.1.1.1.1.1.1) and Its Heterometallic Complexes with Palladium–Carbon Bonds

Cited by 56 publications

References 49 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

Subporphyrins: A Legitimate Ring-Contracted Porphyrin with Versatile Electronic and Optical Properties

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