Spin effects in intramolecular electron transfer in naproxen-N-methylpyrrolidine dyad

Magin, Ilya M.; Polyakov, Nikolay E.; Khramtsova, Ekaterina A.; Kruppa, Alexander I.; Tsentalovich, Yu. P.; Leshina, Tatyana V.; Miranda, Miguel A.; Nuin, Edurne; Marín, M. Luisa

doi:10.1016/j.cplett.2011.09.057

Cited by 9 publications

(25 citation statements)

References 37 publications

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“…34,[37][38][39][40] This impact of polarity on CIDNP efficiency has been shown earlier for the photoinduced ET in the short dyad NPX -Pyr 4(a,b). 22,24 Dyads NPX-AA-Pyr 2(a,b) and NPX-CyAA-Pyr 3(a,b) also demonstrate the dependence of 1 H CIDNP effects at N-methylpyrrolidine fragments, obtained with the help of a pseudo-steady state pulses sequence, 41 on the solvent permittivity (Fig. 6, only (b)-diastereomers are shown).…”

Section: Cidnp Effects In (Rs)-and (Ss)-dyads and Their Relationshimentioning

confidence: 99%

“…[22][23][24] It should be noted that CIDNP is considered to be one of the most informative methods to identify short-lived paramagnetic particles, 28 and its use together with the fluorescence data can let one perform quantitative analysis of a process.…”

Section: Impact Of Chirality On the Photoinduced Charge Transfer In Lmentioning

confidence: 99%

“…[19][20][21][22][23][24] Since the days of Jabotinsky's works, the photochemical generation of a pair of paramagnetic particles has been used for the modeling of biological processes such as the elementary steps of enzymatic oxygenation and drug-transport protein binding. [25][26][27] This approach is promising in several aspects.…”

Section: Impact Of Chirality On the Photoinduced Charge Transfer In Lmentioning

confidence: 99%

“…Dependence of the free energies of the radical ion pair (RIP) of the Nmethylpyrrolidine 22 radical cation, and the methoxynaphthalene radical anion, and the exciplex in this system, calculated using the Rehm-Weller equation 36 …”

Section: Figmentioning

confidence: 99%

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Impact of chirality on the photoinduced charge transfer in linked systems containing naproxen enantiomers

Khramtsova

Sosnovsky

Ageeva

et al. 2016

Phys. Chem. Chem. Phys.

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The model reaction of photoinduced donor-acceptor interaction in linked systems (dyads) has been used to study the comparative reactivity of a well-known antiinflammatory drug, (S)-naproxen (NPX) and its (R)-isomer. (R)-or (S)-NPX in these dyads is linked to (S)-N-methylpyrrolidine (Pyr) using a linear or cyclic amino acid bridge (AA or CyAA), to give (R)-/(S)-NPX-AA-(S)-Pyr flexible and (R)-/(S)-NPX-CyAA-(S)-Pyr rigid dyads. The donor-acceptor interaction is reminiscent of the binding (partial charge transfer, CT) and electron transfer (ET) processes involved in the extensively studied inhibition of the cyclooxygenase enzymes (COXs) by the NPX enantiomers. Besides that, both optical isomers undergo oxidative metabolism by enzymes from the P450 family, which also includes ET. The scheme proposed for the excitation quenching of the (R)-and (S)-NPX excited state in these dyads is based on the joint analysis of the chemically induced dynamic nuclear polarization (CIDNP) and fluorescence data. The 1 H CIDNP effects in this system appear in the back electron transfer in the biradical-zwitterion (BZ), which is formed via dyad photoirradiation. The rate constants of individual steps in the proposed scheme and the fluorescence quantum yields of the local excited (LE) states and exciplexes show stereoselectivity. It depends on the bridge's length, structure and solvent polarity. The CIDNP effects (experimental and calculated) also demonstrate stereodifferentiation. The exciplex quantum yields and the rates of formation are larger for the dyads containing (R)-NPX, which let us suggest a higher contribution from the CT processes with the (R)-optical isomer.

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Section: Cidnp Effects In (Rs)-and (Ss)-dyads and Their Relationshimentioning

confidence: 99%

Section: Impact Of Chirality On the Photoinduced Charge Transfer In Lmentioning

confidence: 99%

Section: Impact Of Chirality On the Photoinduced Charge Transfer In Lmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

See 2 more Smart Citations

Impact of chirality on the photoinduced charge transfer in linked systems containing naproxen enantiomers

Khramtsova

Sosnovsky

Ageeva

et al. 2016

Phys. Chem. Chem. Phys.

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“…24 For the purposes of this study, this fact is crucial because as described above, both the singlet and triplet spin states of the biradical ion participate in the quenching of the dyad's excited state. 11 Fig . 4 shows the calculated CIDNP field dependences in the case when recombination proceeds simultaneously from the singlet and triplet spin states of radical pair (RP).…”

Section: Cidnp Field Dependence Theoretical Descriptionmentioning

confidence: 99%

Low field photo-CIDNP in the intramolecular electron transfer of naproxen–pyrrolidine dyads

Magin

Polyakov

Kruppa

et al. 2016

Phys. Chem. Chem. Phys.

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Photoinduced processes with partial (exciplex) and full charge transfer in donor-acceptor systems are of interest because they are frequently used for modeling drug-protein binding. Low field photo-CIDNP (chemically induced dynamic nuclear polarization) for these processes in dyads, including the drug, (S)-and (R)-naproxen and (S)-N-methyl pyrrolidine in solutions with strong and weak permittivity have been measured. The dramatic influence of solvent permittivity on the field dependence of the N-methyl pyrrolidine 1 H CIDNP effects has been found. The field dependences of both (R,S)-and (S,S)-dyads in a polar medium are the curves with a single extremum in the area of the S-T+ terms intersection. Moreover, the CIDNP field dependences of the same protons measured in a low polar medium present curves with several extrema. The shapes of the experimental CIDNP field dependence with two extrema have been described using the Green function approach for the calculation of the CIDNP effects in the system without electron exchange interactions. The article discusses the possible causes of the differences between the CIDNP field dependence detected in a low-permittivity solvent with the strong Coulomb interactions and in a polar solvent.

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Configuration‐Dependent Photoinduced Electron Transfer in Diastereomeric Naphthalene‐Amino‐Naphthalene Triads

Nuin

Sastre

Pischel

et al. 2015

Chemistry A European J

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Novel diastereomeric triads containing two naphthalene chromophores have been designed in which an electron-donating amine moiety is covalently integrated into the connecting bridge. Photophysical studies (steady-state and time-resolved fluorescence) in solvents of different polarity have been performed. A remarkable stereodifferentiation in the intramolecular fluorescence quenching was found in acetonitrile. Laser flash photolysis gave rise to naphthalene-derived radical cations, which were also quenched by the amine with an even higher degree of stereodifferentiation. The results are in agreement with thermodynamic estimations and indicate that photoinduced electron transfer (PET) is the main quenching pathway. Furthermore, theoretical calculations have allowed us to explain the experimentally observed stereodifferentiation in PET quenching.

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Spin effects in intramolecular electron transfer in naproxen-N-methylpyrrolidine dyad

Cited by 9 publications

References 37 publications

Impact of chirality on the photoinduced charge transfer in linked systems containing naproxen enantiomers

Impact of chirality on the photoinduced charge transfer in linked systems containing naproxen enantiomers

Low field photo-CIDNP in the intramolecular electron transfer of naproxen–pyrrolidine dyads

Configuration‐Dependent Photoinduced Electron Transfer in Diastereomeric Naphthalene‐Amino‐Naphthalene Triads

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