Ring size selective synthesis of meso-aryl expanded porphyrins

Taniguchi, Ryuichiro; Shimizu, Soji; Suzuki, Masaaki; Shin, Ji Young; Furuta, Hiroyuki; Osuka, Atsuhiro

doi:10.1016/s0040-4039(03)00328-9

Cited by 85 publications

(57 citation statements)

References 8 publications

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“…[4] The clever conceptual combination of a flexible polyene chain containing one E double bond with a rigid bianthraquinodimethane moiety resulted in Möbius-stabilized [16]annulene 3 (Scheme 2). Its synthesis was realized through stepwise irradiation starting from tetradehydrodianthracene 1 and syn-tricyclooctadiene 2.…”

Section: Aromaticity · Expanded Porphyrins · Möbius Aromaticity · Pormentioning

confidence: 99%

The Porphyrin Twist: Hückel and Möbius Aromaticity

Jux

2008

Angew Chem Int Ed

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Section: Aromaticity · Expanded Porphyrins · Möbius Aromaticity · Pormentioning

confidence: 99%

The Porphyrin Twist: Hückel and Möbius Aromaticity

Jux

2008

Angew Chem Int Ed

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“…Ring-size selective syntheses [21] of meso-trifluoromethylsubstituted expanded porphyrins have been explored by using oligopyrrolic precursors 11, 12, and 13 (Schemes 2 and 3). meso-Trifluoromethyl-substituted dipyrromethane [22] 10 was treated with four equivalents of TFAA in THF at À20 8C to give 2-trifluoroacetyl-6-trifluoromethyldipyrro-A C H T U N G T R E N N U N G methane in 82-88 % yield, which was quantitatively reduced with NaBH 4 to its carbinol 11.…”

Section: Introductionmentioning

confidence: 99%

meso‐Trifluoromethyl‐Substituted Expanded Porphyrins

Shimizu

Aratani

Osuka

2006

Chemistry A European J

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133

111

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A series of meso-trifluoromethyl-substituted expanded porphyrins, including N-fused [24]pentaphyrin 3, [28]hexaphyrin 4, [32]heptaphyrin 5, [46]decaphyrin 6, and [56]dodecaphyrin 7, were synthesized by means of an acid-catalyzed one-pot condensation reaction of 2-(2,2,2-trifluoro-1-hydroxyethyl)pyrrole (1) as the first examples bearing meso-alkyl substituents. Besides these products, porphyrin 2 and two calix[5]phyrins 8 and 9 were also obtained. [28]Hexaphyrin 4 was quantitatively oxidized to [26]hexaphyrin 14 with MnO(2). These expanded porphyrins have been characterized by mass spectrometry, (1)H and (19)F NMR spectroscopy, and UV/Vis spectroscopy. The single-crystal structures have been determined for 3, 4, 6, 7, and 14. The N-fused [24]pentaphyrin 3 displays a distorted structure containing a tricyclic fused moiety that is similar to those of meso-aryl-substituted counterparts, whereas 8 and 9 are indicated to take roughly planar conformations with an inverted pyrrole opposite to the sp(3)-hybridized meso-carbon atom. Both [28]- and [26]hexaphyrins 4 and 14 have figure-of-eight structures. Solid-state structures of the decaphyrin 6 and dodecaphyrin 7 are remarkable, exhibiting a crescent conformation and an intramolecular two-pitch helical conformation, respectively.

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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.…”

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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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Ring size selective synthesis of meso-aryl expanded porphyrins

Cited by 85 publications

References 8 publications

The Porphyrin Twist: Hückel and Möbius Aromaticity

The Porphyrin Twist: Hückel and Möbius Aromaticity

meso‐Trifluoromethyl‐Substituted Expanded Porphyrins

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

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