Singlet State Cis,Trans Photoisomerization and Intersystem Crossing of 1-Arylpropenes

Lewis, Frederick D.; Bassani, Dario M.; Caldwell, Richard A.; Unett, D. J.

doi:10.1021/ja00102a014

Cited by 44 publications

(76 citation statements)

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“…[38] The qualitative aspects of the diagram are in agreement with conical intersection treatments, which similarly involve an activation energy on the path between the excited state and the transition state from which the return to the initial state or the formation of the product occurs. [39,40] The overall isomerization rate constant k for the forward and back reactions will depend on 1) the extinction coefficient of each of the two isomers; 2) the oscillator strength of the photo-induced excitation to the reactive (p*) excited state; 3) the rate constant of the process of S 1 !…”

Section: Analysis Of the Temperature Dependence Of The Reactionsupporting

confidence: 74%

Supramolecular Solids as a Medium for Single‐Crystal‐to‐Single‐Crystal E/Z Photoisomerization: Kinetic Study of the Photoreactions of Two Zn‐Coordinated Tiglic Acid Molecules

Zheng

Velde

Messerschmidt

et al. 2007

Chemistry A European J

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[Zn(TA)2(H2O)2] (H-TA=tiglic acid) has been embedded in a framework composed of CECR (CECR=C-ethylcalix[4]resorcinarene) molecules to examine its E-->Z photoisomerization in a periodic framework. The photoisomerization of tiglic acid in CECR-[Zn(TA)2(H2O)2]4 H2O proceeds without the [2+2]-dimerization reaction that often occurs in crystals of uncomplexed analogues, and without breakdown of the crystal lattice that frequently occurs in neat crystals. The two Zn-coordinated TA molecules are located in different size cavities. The rate constants of the isomerization reaction are strongly affected by the size of the reaction cavity. Analysis of the temperature dependence of the reaction rates and the occupancies in the final photostationary state shows that the activation energies and the standard enthalpies of activation are dependent on the difference between the reaction cavities. This is the first quantitative diffraction study of solid-state E/Z isomerization of a metal-coordinated ligand in a periodic host environment.

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Section: Analysis Of the Temperature Dependence Of The Reactionsupporting

confidence: 74%

Supramolecular Solids as a Medium for Single‐Crystal‐to‐Single‐Crystal E/Z Photoisomerization: Kinetic Study of the Photoreactions of Two Zn‐Coordinated Tiglic Acid Molecules

Zheng

Velde

Messerschmidt

et al. 2007

Chemistry A European J

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show abstract

“…Similar to other systems that undergo photo-isomerization, there must exist an excited triplet state (T 1 ) surface lower in energy relative to that of the S 1 surface, as depicted in Figure 7 (37). Just as for the S 1 state, the T 1 state should also be stabilized by the twisted intermediate conformation.…”

Section: Discussionmentioning

confidence: 96%

Internally labeled Cy3/Cy5 DNA constructs show greatly enhanced photo-stability in single-molecule FRET experiments

Lee

Hippel

Marcus

2014

Nucleic Acids Research

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DNA constructs labeled with cyanine fluorescent dyes are important substrates for single-molecule (sm) studies of the functional activity of protein–DNA complexes. We previously studied the local DNA backbone fluctuations of replication fork and primer–template DNA constructs labeled with Cy3/Cy5 donor–acceptor Förster resonance energy transfer (FRET) chromophore pairs and showed that, contrary to dyes linked ‘externally’ to the bases with flexible tethers, direct ‘internal’ (and rigid) insertion of the chromophores into the sugar-phosphate backbones resulted in DNA constructs that could be used to study intrinsic and protein-induced DNA backbone fluctuations by both smFRET and sm Fluorescent Linear Dichroism (smFLD). Here we show that these rigidly inserted Cy3/Cy5 chromophores also exhibit two additional useful properties, showing both high photo-stability and minimal effects on the local thermodynamic stability of the DNA constructs. The increased photo-stability of the internal labels significantly reduces the proportion of false positive smFRET conversion ‘background’ signals, thereby simplifying interpretations of both smFRET and smFLD experiments, while the decreased effects of the internal probes on local thermodynamic stability also make fluctuations sensed by these probes more representative of the unperturbed DNA structure. We suggest that internal probe labeling may be useful in studies of many DNA–protein interaction systems.

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“…Dimers 6a , 6b and 6d have been found among cis -anethole photodimerization (at 313 nm) products, but not among trans -anethole irradiation products, formed in the presence or absence of sensitizer [ 10 , 24 ]. Their formation during trans -anethole UV-Vis irradiation may be explained by the reaction of cis -anethole formed during the experiment.…”

Section: Resultsmentioning

confidence: 99%

“…Caldwell et al [ 24 ] observed cis -anethole configuration retention in [2+2] reactions with singlet 9-cyanophenanthrene. The dimer structures proposed here maintain the cis -anethole stereochemistry.…”

Section: Resultsmentioning

confidence: 99%

“…Since cis -anethole is being formed, encounters of 1 t -A* with cis -anethole are much less likely than those with trans -anethole. Additionally, cis -anethole has been reported as less reactive than trans -anethole in the photocycloaddition with 9-cyanophenanthrene and 6-methylphenantridine [ 24 ]. The much higher abundance of 6c and 6e dimers in comparison with 6a and 6b dimers is another consequence of this reaction rate difference.…”

Section: Resultsmentioning

confidence: 99%

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Anethole Isomerization and Dimerization Induced by Acid Sites or UV Irradiation

2010

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The formation of cis-anethole and various dimers as a result of the exposure of trans-anethole to microporous solid acids (dealuminated HY zeolites), or UV-Vis irradiation was established by means of high resolution gas chromatography coupled to mass spectrometry. 3,4-bis-(4-Methoxyphenyl)-(E)-hex-2-ene was the most abundant compound among eight different methoxyphenyl-disubstituted hexenes produced by electrophilic addition and elimination reactions induced by HY zeolites. (1a,2a,3b,4b)-1,2-bis(4-Methoxyphenyl)-3,4-dimethylcyclobutane was the principal component in the mixture of 5 methoxyphenyl-disubstituted cyclobutanes found, together with cis-anethole, after UV-Vis irradiation of a trans-anethole solution in toluene.

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Singlet State Cis,Trans Photoisomerization and Intersystem Crossing of 1-Arylpropenes

Cited by 44 publications

References 0 publications

Supramolecular Solids as a Medium for Single‐Crystal‐to‐Single‐Crystal E/Z Photoisomerization: Kinetic Study of the Photoreactions of Two Zn‐Coordinated Tiglic Acid Molecules

Supramolecular Solids as a Medium for Single‐Crystal‐to‐Single‐Crystal E/Z Photoisomerization: Kinetic Study of the Photoreactions of Two Zn‐Coordinated Tiglic Acid Molecules

Internally labeled Cy3/Cy5 DNA constructs show greatly enhanced photo-stability in single-molecule FRET experiments

Anethole Isomerization and Dimerization Induced by Acid Sites or UV Irradiation

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