Formation and behavior of intramolecular &lt;i&gt;N-&lt;/i&gt;(styrylalkyl)aniline exciplexes

Lewis, Frederick D.; Wagner-Brennan, Jill M.; Miller, Alan M.

doi:10.1139/cjc-77-5-6-595

Cited by 8 publications

(5 citation statements)

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“…Preliminary studies of the photochemical reactions of the aminonaphthalenes with PP indicate that primary and secondary amines undergo N−H addition to the styrene double bond in nonpolar solvents, but that tertiary amines are not photochemical reactive . This behavior is similar to that of the intramolecular N- (styrylalkyl)aniline exciplexes which we have recently investigated …”

Section: Resultssupporting

confidence: 83%

“…Fluorescence quenching of aromatic amines by chlorobenzenes, chloromethanes, and benzonitrile 9 has also been reported; however, exciplex formation was not observed in these reactions. Intramolecular exciplex formation between singlet dimethylaniline and alkene or styrene acceptors has been observed by Hansen and co-workers 10 and in this laboratory …”

supporting

confidence: 61%

“…Quenching of singlet aromatic amines by ground state acceptors can also result in electron transfer. − In comparison to the quenching of singlet acceptors by aromatic amines, quenching of singlet aromatic amines by ground state acceptors has received limited attention. Beens and Weller 1a noted the failure of dimethylaniline and benzene to form an exciplex and suggested that it might be a consequence of limited orbital overlap.…”

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confidence: 99%

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Formation and Anomalous Behavior of Aminonaphthalene−Cinnamonitrile Exciplexes

2000

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The solvent dependence of the electronic spectra of several 1-aminonaphthalenes and 2-aminonaphthalenes in the absence and presence of two styrene derivatives, cinnamonitrile and 1-phenylpropene, has been investigated. The absorption maxima of the aminonaphthalenes are dependent upon both the polarity and hydrogen-bond donor and acceptor properties of the solvent and display both red and blue solvent shifts. The fluorescence maxima are more sensitive to solvent polarity than are the absorption maxima and display red shifts in both non-hydroxylic and hydroxylic solvents. The excited state dipole moments of the 1-aminonaphthalenes are larger than those of the 2-aminonaphthalenes. Quenching of the aminonaphthalene fluorescence by cinnamonitrile occurs with diffusion-controlled rates in all solvents, in accord with the occurrence of exergonic electron transfer. Exciplex fluorescence is observed only for the tertiary aminonaphthalenes in nonpolar solvents. The exciplex fluorescence displays anomalous temperature dependence in hexane solution, an increase in temperature resulting in blue-shifted exciplex fluorescence and an increase in the exciplex decay time. Quenching of the aminonaphthalene fluorescence by 1-phenylpropene is slower than diffusioncontrolled and is not accompanied by exciplex fluorescence.Aromatic amines are strong electron donors that have been widely employed in investigations of exciplex formation and photoinduced electron transfer. [1][2][3][4][5] In most such studies, ground state N,N-dialkylanilines have been used to quench relatively nonpolar singlet acceptors. Since the exciplex or contact ion pair formed in such reactions is more polar than the locally excited singlet state, solvent polarity has a pronounced effect on exciplex formation and behavior. Increasing solvent polarity has little effect on the fluorescence of the locally excited singlet but causes a red shift in the exciplex emission and a decrease in the exciplex fluorescence intensity and lifetime due increased rates of nonradiative decay or ionic dissociation. The formation of fluorescent exciplexes has been observed for N,N-dialkylanilines but not for primary or secondary anilines. 2 The absence of exciplex fluorescence from exciplexes formed by secondary and tertiary anilines has been attributed to proton transfer processes and enhanced intersystem crossing. 2,5 Quenching of singlet aromatic amines by ground state acceptors can also result in electron transfer. [6][7][8][9][10][11] In comparison to the quenching of singlet acceptors by aromatic amines, quenching of singlet aromatic amines by ground state acceptors has received limited attention. Beens and Weller 1a noted the failure of dimethylaniline and benzene to form an exciplex and suggested that it might be a consequence of limited orbital overlap. Intermolecular exciplex formation upon quenching of 2-dimethylaminonaphthalene by dimethylphthalates in nonpolar solvents was observed by Kaneta and Kiozumi. 6 Fluorescence

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Section: Resultssupporting

confidence: 83%

supporting

confidence: 61%

mentioning

confidence: 99%

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Formation and Anomalous Behavior of Aminonaphthalene−Cinnamonitrile Exciplexes

2000

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“…A similar red shift was observed under the same conditions when comparing the emission spectra of 1c and 1c - H (panel B). Thus, the fluorescence spectra of 1b , c in hexane can be safely attributed to formation of intramolecular charge-transfer exciplexes. 8d, This effect is also observed in acetonitrile (data not shown), although the changes associated with exciplex formation are less marked.…”

mentioning

confidence: 79%

“…It is known that irradiation of 1a leads to formation of a 5 -membered ring product via intramolecular excited-state electron transfer . Some of its analogues exhibit emission spectra which have been tentatively assigned to intramolecular exciplexes. 8d, A simplified mechanism for the photocyclization of o -allylanilines is shown in Scheme . Compounds 1b and 1c possess a chiral carbon atom, due to substitution at C-2; this would allow in both cases formation of two diastereoisomers upon cyclization.…”

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Entropy-Controlled Diastereoselectivity in the Photocyclization of Rigid Derivatives ofo-Allylaniline

et al. 2002

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Two rigid derivatives of o-allylaniline, namely 8-allyl-2-phenyl-1,2,3,4-tetrahydroquinoline (1b) and 7-(trans-2-cinnamyl)-2-methylindoline (1c), have been chosen as suitable systems to study the potential stereoselectivity of the photocyclization process. Photolysis of 1b leads to a mixture of diastereomeric lilolidines 4 (trans/cis), while 1cproduces a mixture of 4 (trans/cis) and the tetrahydropyrrolo[3,2,1-hi]indole derivatives 5 (trans/cis). To disclose whether the diastereoselectivity could be entropy dependent, photolysis of 1b and 1c has been performed at several temperatures. In both cases, linear relationships have been observed when ln(k(t)/k(c)) (the relative reaction rate constants calculated from the diastereomeric excess) is plotted against the reciprocal temperatures. However, significant entropy-controlled diastereoselectivity has only been found for the photocyclization of 1c to 4. The fluorescence spectra of 1b,c show formation of intramolecular charge-transfer exciplexes, which is in agreement with the proposed excited-state electron-transfer mechanism for photocyclization.

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The Spectroscopy, Photophysics and Photochemistry of Anilines

Yang

2009

Patai's Chemistry of Functional Groups

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Formation and behavior of intramolecular <i>N-</i>(styrylalkyl)aniline exciplexes

Cited by 8 publications

References 2 publications

Formation and Anomalous Behavior of Aminonaphthalene−Cinnamonitrile Exciplexes

Formation and Anomalous Behavior of Aminonaphthalene−Cinnamonitrile Exciplexes

Entropy-Controlled Diastereoselectivity in the Photocyclization of Rigid Derivatives ofo-Allylaniline

The Spectroscopy, Photophysics and Photochemistry of Anilines

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