Photochemical Rearrangement of a 19‐Membered Azoxybenzocrown: Products and their Properties

Wagner‐Wysiecka, Ewa; Szulc, Paulina; Luboch, Elżbieta; Chojnacki, Jarosław; Szwarc-Karabyka, Katarzyna; Łukasik, Natalia; Murawski, Miłosz; Kosno, Michał

doi:10.1002/cplu.202000474

Cited by 5 publications

(55 citation statements)

References 50 publications

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“…The atypical products of rearrangement of azoxy compounds under both chemical- and photo-stimulated reactions have been reported by other authors [ 32 , 33 ] and by us [ 26 ].…”

Section: Resultssupporting

confidence: 76%

“…Until now, many derivatives of these class of compounds have been obtained and explored by our team, e.g., [ 16 , 17 , 18 , 19 ]. Currently, our efforts are focused on the preparation and study of the properties of hydroxyazobenzocrowns ( Figure 1 ) [ 20 , 21 , 22 , 23 , 24 , 25 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

“…Various procedures can lead to hydroxy–azo compounds, including macrocyclic procedures [ 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Among others, azoxy compounds can be transformed into hydroxy–azo compounds by a process known as Wallach rearrangement [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

“…In this reaction, p -hydroxyderivatives are formed mainly, whereas under photo-illumination of azoxy derivatives, o -hydroxy-substituted azo compounds dominate [ 28 ]. Recently, we presented the products of the photochemical rearrangement of 19-membered azoxybenzocrown [ 26 ]. Our studies have shown that, besides the expected products of transformations of macrocyclic azoxy compounds, atypical ones can also be formed.…”

Section: Introductionmentioning

confidence: 99%

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Products of Photo- and Thermochemical Rearrangement of 19-Membered di-tert-Butyl-Azoxybenzocrown

et al. 2022

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The preparation and characterization of products of the photochemical and thermochemical rearrangements of 19-membered azoxybenzocrowns with two, bulky, tert-butyl substituents in benzene rings in the para positions to oligooxyethylene fragments (meta positions to azoxy group, i.e., t-Bu-19-Azo-O have been presented. In photochemical rearrangement, two colored typical products were expected, i.e., 19-membered o-hydroxy-m,m′-di-tert-butyl-azobenzocrown (t-Bu-19-o-OH) and 19-membered p-hydroxy-m,m′-di-tert-butyl-azobenzocrown (t-Bu-19-p-OH). In experiments, two colored atypical macrocyclic derivatives, one 6-membered and one 5-membered ring, bearing an aldehyde group (t-Bu-19-al) or intramolecular ester group (t-Bu-20-ester), were obtained. Photochemical rearrangement led to one more macrocyclic product being isolated and identified: a 17-membered colorless compound, without an azo moiety, t-Bu-17-p-OH. The yield of the individual compounds was significantly influenced by the reaction conditions. Thermochemical rearrangement led to t-Bu-20-ester as the main product. The structures of the four crystalline products of the rearrangement—t-Bu-19-o-OH, t-Bu-19-p-OH, t-Bu-20-ester and t-Bu-17-p-OH—were determined by the X-ray method. Structures in solution of atypical derivatives (t-Bu-19-al and t-Bu-20-ester) and t-Bu-19-p-OH were defined using NMR spectroscopy. For the newly obtained hydroxyazobenzocrowns, the azo–phenol⇄quinone–hydrazone tautomeric equilibrium was investigated using spectroscopic methods. Complexation studies of alkali and alkaline earth metal cations were studied using UV-Vis absorption spectroscopy. 1H NMR spectroscopy was additionally used to study the cation recognition of metal cations. Cation binding studies in acetonitrile have shown high selectivity towards calcium over magnesium for t-Bu-19-o-OH.

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“…The atypical products of rearrangement of azoxy compounds under both chemical- and photo-stimulated reactions have been reported by other authors [ 32 , 33 ] and by us [ 26 ].…”

Section: Resultssupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Products of Photo- and Thermochemical Rearrangement of 19-Membered di-tert-Butyl-Azoxybenzocrown

et al. 2022

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“…and constructed in cooperation with the Enviklim Company (Gdańsk, Poland). The reactor was equipped with 3 UVA diode arrays: 2xUV-D6565-4LED, 40 W and 1xUV-D6565-15LED, 150 W (Enviklim Company, Gdańsk, Poland) with a 365–370 nm wavelength [ 45 , 46 ]. Detailed conditions are summarized in Table 1 .…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Phosphonated Carbon Nanotubes: New Insight into Carbon Nanotubes Functionalization

et al. 2021

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Carbon nanotubes were successfully functionalized for the first time in a free radical phosphonylation reaction. Three synthetic protocols were proposed. Carbon nanotubes and diethylphosphite reacted in the presence of known radical initiator, such as azobisisobutyronitrile, single electron oxidant—Mn(OAc)3, or under UV radiation. The functionalized material was fully characterized by means of spectroscopic methods, together with microscopic, surface area and thermogravimetric analyses. UV-illumination was found to be the most effective approach for introducing phosphonates onto carbon nanotubes. X-ray photoelectron spectroscopy analysis showed 6% phosphorus in this sample. Moreover, the method was performed at room temperature for only one hour, using diethylphosphite as a reactant and as a solvent. The functionalized carbon nanotubes showed an improved thermal stability, with a decomposition onset temperature increase of more than 130 °C. This makes it very promising material for flame retarding applications.

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Molecular Rearrangements

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2024

Organic Reaction Mechanisms 2020

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Photochemical Rearrangement of a 19‐Membered Azoxybenzocrown: Products and their Properties

Cited by 5 publications

References 50 publications

Products of Photo- and Thermochemical Rearrangement of 19-Membered di-tert-Butyl-Azoxybenzocrown

Products of Photo- and Thermochemical Rearrangement of 19-Membered di-tert-Butyl-Azoxybenzocrown

Synthesis of Phosphonated Carbon Nanotubes: New Insight into Carbon Nanotubes Functionalization

Molecular Rearrangements

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