A 20π‐Electron Heteroporphyrin Containing a Thienopyrrole Unit

Chang, Yi; Chen, Huachao; Zhou, Zhikuan; Zhang, Yue; Schütt, Christian; Herges, Rainer; Shen, Zhen

doi:10.1002/anie.201204954

Cited by 44 publications

(40 citation statements)

References 63 publications

(28 reference statements)

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“…1 Their aromatic character depends on the number and properties of the heteroatoms and what kind of substituents that are conjugated with the main macrocycle. [2][3][4][5][6][7] Many antiaromatic porphyrinoids are stable with interesting properties for technological devices. 2,8,9 The term antiaromatic was used for the first time by Breslow in 1965.…”

Section: Introductionmentioning

confidence: 99%

Computational Studies of Aromatic and Photophysical Properties of Expanded Porphyrins

et al. 2018

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Magnetically induced current densities and ring-current pathways have been calculated at density functional theory (DFT) and second-order Møller-Plesset perturbation theory (MP2) levels of theory for a set of expanded porphyrins consisting of five or six pyrrolic rings. The studied molecules are sapphyrin, cyclo[6]pyrrole, rubyrin, orangarin, rosarin, and amethyrin. Different functionals have been employed to assess the functional dependence of the ring-current strength susceptibility. Vertical singlet and triplet excitation energies have been calculated at the second-order approximate coupled cluster (CC2), expanded multiconfigurational quasi-degenerate perturbation theory (XMC-DPT2), and time-dependent density functional theory levels. The lowest electronic transition of the antiaromatic molecules was found to be pure magnetic transitions providing an explanation for the large paratropic contribution to the total current density. Rate constants for different nonradiative deactivation channels of the lowest excited states have been calculated yielding lifetimes and quantum yields of the lowest excited singlet and triplet states. The calculations show that the spin-orbit interaction between the lowest singlet ( S) and triplet ( T) states of the antiaromatic molecules is strong, whereas for the aromatic molecule the spin-orbit coupling vanishes. The experimentally detected fluorescence from S to S of amethyrin has been explained. The study shows that there are correlations between the aromatic character and optical properties of the investigated expanded porphyrins.

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Section: Introductionmentioning

confidence: 99%

Computational Studies of Aromatic and Photophysical Properties of Expanded Porphyrins

et al. 2018

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“…Compounds 4·PF 6 and 5·PF 6 exhibit porphyrin-like Soret and Q-bands, reflecting their 14π-electron aromatic nature. [39][40][41][42][43][44][45][46][47] However, to date, anti-aromatic ring-contracted porphyrins have scarcely been reported. Compounds 4·PF 6 and 5·PF 6 show fluorescence at 578 nm (fluorescence quantum yield, Φ f = 2.6 % and fluorescence life time, τ f = 1.1 ns) and 616 nm (Φ f = 9.0 %, τ f = 2.3 ns), respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, porphyrin analogues have been reported to be suitable platforms for the construction of antiaromatic compounds. [39][40][41][42][43][44][45][46][47] However, to date, anti-aromatic ring-contracted porphyrins have scarcely been reported. Shinokubo and co-workers established methods for the synthesis of norcorroles with anti-aromatic characteristics that are stable compounds under ambient conditions, [48][49][50] but interestingly they show unique reactivity towards nucleophiles.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of [14]Oxatriphyrins(2.1.1) and Their Transformation into Ethane‐Bridged Oxatripyrrins by Boron Complexation

et al. 2018

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[14]Oxatriphyrins(2.1.1) incorporating a furan moiety in the macrocycle have been synthesized by intramolecular McMurry coupling of oxatripyrromethane followed by oxidation. The [14]oxatriphyrins(2.1.1) are highly planar structures with 14π‐electron aromaticity, inducing typical porphyrin‐like absorption and fluorescence features. Compared with [14]thiatriphyrin(2.1.1) and arene‐fused oxatriphyrins(2.1.1), arene‐unperturbed [14]oxatriphyrins(2.1.1) exhibit stronger aromatic characteristics and fluorescence properties. The borylation of [14]oxatriphyrins(2.1.1) with dichloro(phenyl)borane resulted in the formation of boron complexes with a reduced olefin bridge. As a result of the reduction, the macrocycles of these boron complexes lost their aromatic properties, although the targeted boron complexes were predicted to have distinct anti‐aromatic properties by DFT calculations. The resultant ethane‐bridged oxatripyrrins exhibit intense emission because of their rigid structures.

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“…7, 54 representing the recently synthesized thienopyrrole core-modified porphyrinoid structures. 182 Tautomer 1-3 is strongly antiaromatic sustaining a ring current of À50.0 nA/T. The pyrrolic ring annelated to the thiophene ring has a very strong diatropic current flow as illustrated Fig.…”

Section: Porphyrinoids With Fused Ringsmentioning

confidence: 98%

Theoretical studies as a tool for understanding the aromatic character of porphyrinoid compounds

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The scientific interest in porphyrinoid based materials is steady growing, since porphyrinoids are not only of biological relevance, but they also show interesting spectroscopic properties that link them to many possible applications such as near infrared dyes, photovoltaic dyes, field-effect transistors, nonlinear optical materials and nanoelectronic devices. 1-8 Biomedical applications of porphyrinoids are of particular importance specially for photomedical applications in cancer treatment, such as photodynamic therapy, multimodal imaging, drug delivery and biosensing. 9-12 Porphyrinoids show also an ability to form complexes with metals with unusual oxidation states and are therefore relevant for catalysis. 13-18 The classic porphyrin molecule can formally be regarded as four pyrrole rings connected to each other by methin bridges. 19 Depending on the localization of the two inner pyrrolic hydrogen atoms the molecule is labeled cis-or trans-porphyrin. However, at room temperature the inner hydrogens generally move around inside the porphyrin ring. 20,21 The more general term porphyrinoids is used for a class of molecules that share the classical porphyrin structure for the macroring but differ for example by bearing various substituents or heteroatoms. Classic porphyrins, chlorins and bacteriochlorins are aromatic molecules satisfying Hückel's (4n þ 2) p-electron count rule for aromaticity. 22,23 There is no doubt that aromaticity is an important concept in chemistry albeit it is still not fully understood and thus continuously under debate. 24-27 Theoretical calculations have shown that the aromatic pathways of

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A 20π‐Electron Heteroporphyrin Containing a Thienopyrrole Unit

Cited by 44 publications

References 63 publications

Computational Studies of Aromatic and Photophysical Properties of Expanded Porphyrins

Computational Studies of Aromatic and Photophysical Properties of Expanded Porphyrins

Synthesis of [14]Oxatriphyrins(2.1.1) and Their Transformation into Ethane‐Bridged Oxatripyrrins by Boron Complexation

Theoretical studies as a tool for understanding the aromatic character of porphyrinoid compounds

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