Time-resolved photo-CIDNP of dibenzyl ketone-β-cyclodextrin inclusion complex

Petrova, S. S.; Kruppa, A.I.; Leshina, Tatyana V.

doi:10.1016/j.cplett.2003.12.036

Cited by 10 publications

(6 citation statements)

References 18 publications

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“…The long residence time of the radicals in the CD means that nuclear spin relaxation will take place before recombination, leading to a decrease in the CIDNP intensity. This is in good agreement with the conclusions of Petrova et al in a CIDNP study of DBK photolysis in unmodified β-CDs. To confirm this for our system, we ran a similar CIDNP experiment, that is, DBK irradiated in randomly methylated β-CDs.…”

Section: Resultssupporting

confidence: 93%

“…Indeed, TREPR and CIDNP have been applied routinely to study radical reactions in other nanoreactors such as micelles and reverse micelles . To the best of our knowledge, there exist only two previous reports of TREPR investigations of photochemical reactions in CDs, , and only one involving the use of the powerful CIDNP experiment in either steady-state or time-resolved mode …”

Section: Introductionmentioning

confidence: 99%

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Supramolecular Photochemistry in β-Cyclodextrin Hosts: A TREPR, NMR, and CIDNP Investigation

et al. 2010

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A systematic investigation of the photochemistry and ensuing radical chemistry of three guest ketones encapsulated in randomly methylated beta-cyclodextrin (beta-CD) hosts is reported. Dibenzyl ketone (DBK), deoxybenzoin (DOB), and benzophenone (BP) triplet states are rapidly formed after photolysis at 308 nm. Time-resolved electron paramagnetic resonance (TREPR) spectroscopy, steady-state NMR spectroscopy, and time-resolved chemically induced nuclear polarization (TR-CIDNP) experiments were performed on the ketone/CD complexes and on the ketones in free solution for comparison. The major reactivity pathways available from these excited states are either Norrish I alpha-cleavage or H-atom abstraction from the interior of the CD capsule or the solvent. The DOB triplet state undergoes both reactions, whereas the DBK triplet shows exclusively alpha-cleavage and the BP triplet shows exclusively H-atom abstraction. Radical pairs are observed in beta-CDs by TREPR, consisting of either DOB or BP ketyl radicals with sugar radicals from the CD interior. The TREPR spectra acquired in CDs are substantially broadened due to strong spin exchange. The electron spin polarization mechanism is mostly due to S-T(0) radical pair mechanism (RPM) in solution but changes to S-T(-) RPM in the CDs due to the large exchange interaction. The TR-CIDNP results confirm the reactivity patterns of all three ketones, and DOB shows strong nuclear spin polarization from a novel rearrangement product resulting from the alpha-cleavage reaction.

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Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Supramolecular Photochemistry in β-Cyclodextrin Hosts: A TREPR, NMR, and CIDNP Investigation

et al. 2010

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“…The list of guest molecules includes, for example, aliphatic‐chain hydrocarbons, aldehydes, ketones, alcohols, carboxylic acids, fatty acids, aromatic hydrocarbons, and also metallic nanoparticles . The formation of a supramolecular complex with metallic nanoparticles is currently of interest .…”

Section: Figurementioning

confidence: 99%

“…The study of host-guest surfacec omplexes leads to the development of molecular sensors [10] and chemical systems capable of gathering, processing and storing information.The list of guest molecules includes, for example, aliphaticchain hydrocarbons, aldehydes, ketones,a lcohols,c arboxylic acids,f atty acids, aromatic hydrocarbons, and also metallic nanoparticles. [11][12][13][14][15][16] The formation of as upramolecular complex with metallic nanoparticles is currently of interest. [17] There are severala pproaches to preparem etallic nanoparticles, and surfactants such as micelles or microemulsions are widely utilized.…”

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confidence: 99%

Surface Nanostructures Composed of Thiolated Cyclodextrin/Au and Fe Species: Gas‐ and Liquid‐Phase Preparation

et al. 2016

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Supramolecular surface nanostructures have application potential as functional devices. The complex combination of thiolated cyclodextrin, chemisorbed on an Au surface (Au-S-CD), with deposited Fe species is studied by secondary ion mass spectrometry. The Fe species are prepared by pulsed laser ablation in water and thermal effusion in vacuum. Using laser ablation in water, the solution of Fe species is dropped on Au-S-CD, where mass peaks at 1227 m/z, 1243 m/z, and 1260 m/z are observed and assigned to C42 H68 O34 SNa-Fe(+) , C42 H68 O34 SK-Fe(+) together with C42 H68 O34 SNa-FeO(+) , and C42 H68 O34 SK-FeO(+) , respectively. On the other hand, laser ablation directly linked to the Au-S-CD surface results in desorption of CD-S. Thermal effusion, even with a cooled surface, was negative with respect to the complex observation. Laser ablation results in the formation of a supramolecular host-guest complex of the form Au-S-CD-Fe, and in the formation of an adduct of the form Au-S-CD-FeO.

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“…10 The reaction mechanism was studied by the CIDNP method. [13][14][15][16][17][18][19][20] The reactivity of supramolecular lappaconitine com plexes with glycyrrhizic acid (GA) is of independent in terest, because the therapeutical effect of lappaconitine is strongly enhanced in the presence of GA with a simulta neous decrease in its toxicity. 21 Similar effects were de tected for several other drugs.…”

Section: Introductionmentioning

confidence: 99%

Redox reactions of natural alkaloid lappaconitine

Polyakov

Leshina

2007

Russ Chem Bull

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A review on redox reactions of natural alkaloid lappaconitine, a known sodium channel blocker, is presented. The NMR and CIDNP data on the mechanism of phototransformation of lappaconitine, in particular, of its paramagnetic species formed by both the direct photolysis and photoinitiated interaction with electron donors and acceptors, are analyzed. Special atten tion is given to the interaction of lappaconitine with amino acids, which are present in the active site of the sodium channel. Hypotheses about a relationship between this process and the mechanism of therapeutic activity of lappaconitine are discussed.

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Time-resolved photo-CIDNP of dibenzyl ketone-β-cyclodextrin inclusion complex

Cited by 10 publications

References 18 publications

Supramolecular Photochemistry in β-Cyclodextrin Hosts: A TREPR, NMR, and CIDNP Investigation

Supramolecular Photochemistry in β-Cyclodextrin Hosts: A TREPR, NMR, and CIDNP Investigation

Surface Nanostructures Composed of Thiolated Cyclodextrin/Au and Fe Species: Gas‐ and Liquid‐Phase Preparation

Redox reactions of natural alkaloid lappaconitine

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