Synthesis of Selenium and Tellurium Core-Modified Azuliporphyrinogens and Benziporphyrinogens and Corresponding Carbaporphyrinoids

Ahmad, Sohail; Singhal, Anchal; Nisa, Kharu; Chauhan, S. M. S.

doi:10.1021/acs.inorgchem.8b00648

Cited by 12 publications

(9 citation statements)

References 49 publications

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“…12 Recently, investigations into telluraporphyrin-type structures have attracted renewed interest 13 and new examples have been reported, including tellurabenziporphyrins 14 and ditelluradiazuliporphyrins. 15 Carbaporphyrinoid systems have been prepared by numerous synthetic strategies. 4,16 A recent innovation in the synthesis of carbaporphyrins involves the utilization of carbatripyrrin intermediates 9 that were easily prepared in three steps from indene (Scheme 1).…”

Section: ■ Introductionmentioning

confidence: 99%

“…Treatment of 4 with hydrochloric acid afforded vacataporphyrin 7 , and ditelluraporphyrins were used to prepare dideazaaporphyrins (divacataporphyrins). , Ditelluraporphyrins have also been used to generate metallaporphyrins such as 8a , b . Recently, investigations into telluraporphyrin-type structures have attracted renewed interest and new examples have been reported, including tellurabenziporphyrins and ditelluradiazuliporphyrins …”

Section: Introductionmentioning

confidence: 99%

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Telluracarbaporphyrins and a Related Palladium(II) Complex: Evidence for Hypervalent Interactions

2021

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The reaction of a carbatripyrrin with a tellurophene dicarbinol in the presence of BF 3 •Et 2 O, followed by oxidation with DDQ, afforded the first example of a telluracarbaporphyrin. Although this system exhibits strongly aromatic characteristics, it is prone to air oxidation, giving rise to a hydroxy derivative that was characterized by X-ray crystallography. The initial telluracarbaporphyrin reacted with palladium(II) acetate to give a stable organometallic complex, and X-ray crystallography showed that the palladium cation was coordinated to all four atoms in the CNTeN core. An oxacarbatripyrrin was also reacted with a tellurophene dialcohol to give an air-stable porphyrin analogue with a CNTeO core. Nonmetalated telluracarbaporphyrins showed relatively short Te−N separations that strongly implied the involvement of hypervalent tellurium interactions. Furthermore, despite the presence of a very large tellurium atom, the tellurophene subunit is not strongly pivoted away from the mean macrocyclic plane as would be expected in the absence of these interactions. The aromatic properties of heterocarbaporphyrins were assessed by proton NMR spectroscopy, NICS calculations, and AICD plots. In addition, the relative stability of hydroxytelluraporphyrins in comparison to their tellurophene oxide tautomers was investigated and the aromatic characteristics of these oxidized structures were evaluated.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Telluracarbaporphyrins and a Related Palladium(II) Complex: Evidence for Hypervalent Interactions

2021

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“…The use of heteroles other than pyrrole rings gives an additional degree of freedom to these molecules, introducing novel coordination environments with different donors, charges, oxidation stages, and architectures, resulting in interesting structural and electronic features . A series of tellurophene-containing calixphyrins, namely, porphomethenes, porphodimethenes, and porphotrimethenes, with one or two tellurophene rings, compiled with pyrrole or non-pyrrolic building blocks, like selenophene, benzene, or azulene, have been reported recently, widening the library of tellurophene macrocycles. ,, Tellurophene and selenophene-containing calixphyrins and porphyrinogenes showed the ability to bind mercury(II) ions, with affinity dependent on the number of sp 3 bridges. , …”

Section: Introductionmentioning

confidence: 99%

Metalation of Tellurophene: Reactivity of 21,23-Ditelluraporphodimethene toward Palladium(II), Platinum(II), and Rhodium(I)

2023

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Ditelluraporphodimethene, a nonaromatic porphyrinoid containing two tellurophene rings, reacted with palladium(II), platinum(II), and rhodium(I) following two different paths. Palladium(II) formed bonds to two tellurium donors of the macrocycle, yielding a side-on coordination compound, with a square planar (Te 2 Cl 2 ) metal ion environment. An alternative reaction path has been observed for ditelluraporphodimethene with platinum(II) or rhodium(I) in high boiling solvents. These conditions led to the profound transformation, that is, one tellurium atom to a metal atom exchange, resulting in the formation of organometallic species containing metallacyclopentadiene rings, that is, 21-platina-23-telluraporphodimethene and 21-rhoda-23-telluraporphodimethene. The substitution reaction proceeded selectively at the tellurophene ring within the conjugated part of the molecule, that is, the tellurophene ring bound to two sp 2 meso-carbon atoms. In the case of platinum, the exchange was accompanied by one meso-aryl ring fusion with the formed platinacyclopentadiene ring, and the platinum(II) macrocycle underwent reversible oxidation with chlorine. The products are stable and represent first nonaromatic examples of metalloporphyrinoids, with a metallacyclopentadiene ring incorporated into a porphodimethene skeleton.

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“…For example, the telluraporphyrins have proven to be active catalysts in the bromination reactions of 4-pentenoic acid and 1,3,5-trimethoxybenzene, which is ascribed to the ease of oxidation of core tellurium and subsequent stabilization of the telluronium cation by the trans atom . The telluroporphyrinoids are very air-sensitive and have a tendency to extrude tellurium atom from the telluorophene ring of porphyrinoid. , A perusal of the literature reveals that the tellurophene-containing porphyrinoids are relatively less explored as compared to other heteroporphyrinoids, which may be due to a lack of easily accessible stable tellurophene-based precursors and the high reactivity of the telluroporphyrinoids. ,− In particular, there are very few reports available on tellurophene-containing expanded porphyrinoids to understand their physicochemical and coordination properties. − Herein, we report the synthesis of different types of novel tellurophene-containing core-modified homopentaphyrins by a [3 + 2] condensation strategy.…”

Section: Introductionmentioning

confidence: 99%

Tellurophene-Containing Core-Modified Pentaphyrin(2.1.1.1.1)s

et al. 2022

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Various core-modified tellurophene-containing pentaphyrin(2.1.1.1.1)s were synthesized via (3 + 2) condensation of 16-telluratripyrrane with different heterodiols under mild acid catalyzed conditions in 5–12% yields. The formation of pentaphyrin (2.1.1.1.1) with a N2O2Te core was not successful due to its inherent instability. The new pentaphyrins were characterized and studied by HR-MS, 1D and 2D NMR, X-ray crystallography for one of the pentaphyrins, absorption and DFT/TD-DFT techniques. The NMR studies indicated their nonaromatic nature. The X-ray structure obtained for pentaphyrin(2.1.1.1.1) with N4Te core revealed that the macrocycle exists in a highly distorted nonplanar structure. The DFT studies showed that the macrocycles are nonaromatic and exists in highly distorted nonplanar geometry. Furthermore, as the core heterocyclic groups at ethene moiety were changed from pyrrole to furan to thiophene to benzene, the macrocycles tended toward more planar structures. The absorption spectra of pentaphyrins showed one strong sharp band in the region of 450–540 nm along with a broad band in the region of 700–800 nm. The pentaphyrin(2.1.1.1.1) with N4Te core upon protonation showed distinct color change in solution and large bathochromic shifts in absorption bands with an absorption in the NIR region.

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Synthesis of Selenium and Tellurium Core-Modified Azuliporphyrinogens and Benziporphyrinogens and Corresponding Carbaporphyrinoids

Cited by 12 publications

References 49 publications

Telluracarbaporphyrins and a Related Palladium(II) Complex: Evidence for Hypervalent Interactions

Telluracarbaporphyrins and a Related Palladium(II) Complex: Evidence for Hypervalent Interactions

Metalation of Tellurophene: Reactivity of 21,23-Ditelluraporphodimethene toward Palladium(II), Platinum(II), and Rhodium(I)

Tellurophene-Containing Core-Modified Pentaphyrin(2.1.1.1.1)s

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