Reactions of intramolecular C-N photocyclization and photoaddition to the double bond of methoxy- and methoxycarbonyl-substituted styrylbenzoquinolines

Будыка, М. Ф.; Li, V. M.; Гавришова, Т. Н.; Поташова, Н. И.

doi:10.1134/s0018143915030066

Cited by 12 publications

(10 citation statements)

References 16 publications

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“…The spectral changes upon 1 photolysis were analogous to those observed earlier for other SBQ dyads, implying the similar reaction, namely, PCA with formation of a cyclobutane derivative 4 , Scheme . The ESI mass‐spectrum of the reaction mixture after photolysis corroborated this assumption, we observed a peak with the same m/z value as the starting dyad (775, MH + ).…”

Section: Methodssupporting

confidence: 75%

“…If photochromes are diarylethylenes, the dyads undergo, besides the (intra‐photochrome) photoisomerization (PI) between trans ‐ and cis ‐isomers, also the (inter‐photochrome) [2+2] photocycloaddition (PCA) with formation of the cyclobutane derivatives. Dyads with styrylquinoline or styrylbenzo[f]quinoline (SBQ) groups as photochromes and ortho ‐xylylene group as a spacer undergo PCA with quantitative formation of a single rctt cyclobutane derivative . The quantum yields of the PI and PCA reactions and the ratio between these parameters depend substantially on the nature and position of the substituents in the styryl fragments of the SBQ‐photochromes …”

Section: Methodsmentioning

confidence: 99%

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Irreversible One‐Way [2+2] Photocycloaddition in Bis‐Styrylbenzo[f]quinoline Dyad: Photoactive and Photoinert Excimers in the Same System

et al. 2018

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Competitive photoprocesses were found in a novel biphotochromic dyad with 3‐styrylbenzo[f]quinoline (SBQ) photochromes ‐ fluorescence and unexpectedly irreversible [2+2] photocycloaddition (PCA) resulting in formation of a cyclobutane derivative with two benzo[f]quinoline (BQ) substituents. No SBQ trans‐cis photoisomerization was observed. Quantum‐chemical DFT calculations predict π‐stacking of the SBQ units in the dyad that hinders trans‐cis photoisomerization but favors a photoactive excimer formation with following PCA. Calculations predict also π‐stacking of the BQ units in the cyclobutane that explains experimentally observed exciton absorption and excimer emission of the latter. The unique property of the cyclobutane excimer is its photoinertness: cyclobutane does not undergo photocycloreversion with ring opening. The photoinert excimer is observed for the first time. Possible reasons of difference between chemical properties of photoactive and photoinert excimers are discussed.

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Section: Methodssupporting

confidence: 75%

Section: Methodsmentioning

confidence: 99%

Irreversible One‐Way [2+2] Photocycloaddition in Bis‐Styrylbenzo[f]quinoline Dyad: Photoactive and Photoinert Excimers in the Same System

et al. 2018

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“…The latter has a characteristic absorption spectrum with maxima at 230, 274, 298, 358, 377 and 398 nm, Figure 3, last spectrum. [9] The formation of ABC was also corroborated by mass spectrometry. In the ESI mass-spectrum of the reaction mixture before irradiation only peak with m/z = 312 (MH +) was observed that corresponded to the protonated E-MSBQ.…”

Section: Resultsmentioning

confidence: 82%

“…The angular annelation gives 3-styrylbenzo[f]quinoline (SBQ), whose de-rivatives (substituted in the styryl group) are able to the CÀN photocyclization. [9] Taking into account the above facts, we synthesized the SBQ bichromophoric dyad 1 (EE-D, Scheme 1) with an ortho-xylylene bridge, wherein a competition between the intramolecular and intermolecular reactions of the SBQ chromophore is possible. Additionally, one could expect an excimer formation that is characteristic for the covalently-linked bichromophoric compounds.…”

Section: Introductionmentioning

confidence: 99%

Interchromophore [2+2]photocycloaddition vs. intrachromophore C‐N photocyclization in bis–styrylbenzoquinoline dyad

2016

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Photophysical and photochemical properties of a novel bichromophoric dyad (EE‐D), where two 3‐styrylbenzo[f]quinoline chromophoric groups (trans‐isomers) are connected by an ortho‐xylylene group, in comparison with the model compound trans‐3‐(3‐methoxystyryl)benzo[f]quinoline (E‐MSBQ), are investigated. The main photochemical reaction of the E‐MSBQ is trans → cis photoisomerization with subsequent intrachromophoric C−N photocyclization and oxidation to a derivative of 12b‐azonia‐benzo[c]chrysene (ABC). In contrast to the E‐MSBQ, upon irradiation of the EE‐D, in addition to photoisomerization, interchromophoric [2+2]photocycloaddition takes place and results in formation of a cyclobutane (CB) derivative. Due to reversibility of photoisomerization, under irradiation, both the E‐MSBQ and the EE‐D can be completely transformed to the ABC and CB derivatives, respectively. DFT calculations taking into account dispersion interactions (hybrid functional M06‐2X) allow explanation of the effective stereospecific [2+2]photocycloaddition in the dyad EE‐D by π‐stacking that orients two SBQ groups head‐to‐head and promotes formation of a single CB isomer.

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“…During the prolonged photolysis of these compounds, the isosbestic points observed at early stages of irradiation disappeared, and there was a gradual decrease in absorption in the LWAB region, which indicated fur ther photochemical reactions leading to consumption of styrylbenzoquinolines. These reactions are side with respect to the photoisomerization reaction; the results of their more detailed study are discussed in the subse quent paper [16]. In the context of the present work, it is important to note that the rates of side reactions are two orders of magnitude below the rate of the photoi somerization reaction; hence, they can be ignored in the analysis of the rate curves in terms of Eq.…”

Section: Resultsmentioning

confidence: 97%

Spectral and luminescent properties and photoisomerization of substituted styrylbenzoquinolines

Будыка

Гавришова

et al. 2015

High Energy Chem

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Derivatives of 2 styrylquinoline (2SQ), due to their photochemical activity, are used to simulate the action of photonic molecular switches and logic gates [1][2][3][4][5]. Photoisomerization quantum yields of these com pounds can reach values of 0.5 and above, but their disadvantage is relatively small fluorescence quantum yields (ϕ fl ), not exceeding a few hundredths [6]. To address this shortcoming, it is necessary to pass to het erodiarylethylenes, which possess pronounced fluo rescent properties (ϕ fl > 0.1), but it is important that the photoactivity of the compounds, that is, ability to photoisomerization, should persist. For example, when passing from 2SQ to the bis quinoline derivative of distyrylbenzene the ϕ fl value increases significantly (up to 0.63), but the quantum yield of the trans-cis photoisomerization reaction of the first double bond EE → ZE decreases steeply (down to 0.03), and the trans-cis photoi somerization reaction of the second double bond ZE → ZZ does not occur [7].It is known that the angular annulation of the quin oline nucleus, that is, passing from 2SQ to 3 styryl benzo[f]quinoline (3SBQ), leads to a significant increase in the fluorescence quantum yield up to 0.74, with the quantum yield of trans-cis photoisomeriza tion retaining a fairly high value (ϕ tc = 0.19), and the quantum yield of the reverse reaction of cis-trans pho toisomerization ϕ ct = 0.38 [8].Note that photoswitchable fluorophores are "real chemical basis" of one of the methods of ultrahigh res olution fluorescent microscopy ("nanoscopy") [9-11], for the development of which the Nobel Prize in Chemistry was awarded in 2014.To find out photochromes of the class of heterodi arylethylenes, being also fluorophores, that is, satisfy ing the conditions ϕ tc > 0.1 and ϕ fl > 0.1, we studied in this work a number of 3SBQ derivatives: trans 3 (3 methoxystyryl)benzo[f]quinoline (3MSBQ), trans 3 (4 methoxystyryl)benzo[f]quinoline (4MSBQ), and trans 3 (4 methoxycarbonylstyryl)benzo[f]quinoline (4MCSBQ) (Scheme 1): N N PHOTOCHEMISTRY Abstract-The spectral, luminescent, and photochemical properties of 3 styrylbenzo[f]quinoline (3SBQ)derivatives containing methoxy and methoxycarbonyl groups have been studied. All of these compounds luminesce in the region of 380-480 nm with quantum yields up to 0.74 and undergo reversible photoisomer ization with quantum yields of 0.2-0.5. It has been found that compounds with a methoxy group at the meta position and a methoxycarbonyl group at the para position of the styryl moiety are unstable photochromes and also undergo other photochemical reactions side relative to photoisomerization. The absorption spectra of the two 3SBQ s conformers calculated by the density functional theory (DFT) method (TD B3LYP/6 31G*) describe well the experimental spectrum. The analysis of the structures of molecular orbitals and tran sitions between them has made it possible to explain the observed effects of substituents on the absorption spectrum of 3SBQ.

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Reactions of intramolecular C-N photocyclization and photoaddition to the double bond of methoxy- and methoxycarbonyl-substituted styrylbenzoquinolines

Cited by 12 publications

References 16 publications

Irreversible One‐Way [2+2] Photocycloaddition in Bis‐Styrylbenzo[f]quinoline Dyad: Photoactive and Photoinert Excimers in the Same System

Irreversible One‐Way [2+2] Photocycloaddition in Bis‐Styrylbenzo[f]quinoline Dyad: Photoactive and Photoinert Excimers in the Same System

Interchromophore [2+2]photocycloaddition vs. intrachromophore C‐N photocyclization in bis–styrylbenzoquinoline dyad

Spectral and luminescent properties and photoisomerization of substituted styrylbenzoquinolines

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