Paramagnetic intermediates in the photolysis of 7-silanorbornadiene studied by means of spin chemistry method

Taraban, Marc B.; Волкова, О. С.; Kruppa, Alexander I.; Plyusnin, Victor F.; Grivin, Vjacheslav P.; Ivanov, Yu. V.; Leshina, Tatyana V.; Egorov, M. P.; Нефедов, О. М.

doi:10.1016/s0022-328x(98)00605-6

Cited by 15 publications

(52 citation statements)

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“…2 [15]. It has been found that the presence of oxygen led to a shift of the extreme position in the field dependence to the high field and to a noticeable increase in the magnitude of MFE [5] (Fig. 3).…”

Section: Resultsmentioning

confidence: 85%

“…The approach developed above was applied to modeling MFEs detected earlier on the product of the photolysis of 7,7'-dimethylsilanorbomadiene in the presence of oxygen and in deaerated solution [5]. According to ref.…”

Section: Resultsmentioning

confidence: 99%

“…3). Several assumptions for the calculation of MFE in this reaction had been made earlier [5,15], but the influence of the added spin of oxygen on the spin evolution in biradicals had not been considered.…”

Section: Resultsmentioning

confidence: 99%

“…As for the value of Jl used in the calculations, it corresponds to the position of the extremum at 24 mT on the above experimental field dependence of MFEs detected in the absence of oxygen [5] (Fig. 3).…”

Section: Resultsmentioning

confidence: 99%

“…These effects clearly indicate that added paramagnetic particles can affect the processes of spin evolution in RPs and RIPs. In particular, there are several examples demonstrating the influence of the third spin on the field dependences o f M F E in biradicals [3,5]. The mechanism o f the action o f the third spin on spin dynamics o f multispin systems (radical triad or tetrad) are partially related with the well-known relaxation effects (mainly due to the dipole-dipole interaction) [2] or to the manifestation of the electron spin exchange o f RP partners with an added spin.…”

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Modeling magnetic field effects in multispin systems

et al. 2004

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A model is proposed for calculating magnetic field effects formed in a radical triad composed of a biradical anda paramagnetic particle. To describe the influence of the "third" spin on the spin evolution in a biradical, the electron spin exchange interaction of the added spin with one of the paramagnetic centers of the biradical has been considered. Calculating the field dependence of the recombination probability of the biradical-oxygen complex revealed both an increase in recombination probability earlier attributed to spin catalysis and the influence of the values and signs of the exchange interaction in the complex on the shape of the magnetic-field effect dependence. Calculation results are in agreement with the experimental data on the photolysis of 7,7'-dimethylsilanorbomadiene in aerated and deaerated solution. lntroductionAt present, the study of the magnetic field and spin effects in multispin systems is the actual problem of spin chemistry. The catalysis of radical reactions in solutions by paramagnetic particles, called "spin catalysis" [1], has been demonstrated in 1994. Later, the influence o f the additional, so-called "third" spin on magnetic-field effects (MFE) in radical ion pairs (RIP) [2, 3] and the influence o f stable radicals on the chemically induced dynamic nuclear polarization (CIDNP) formation in a radical pair (RP) [4] have been described. These effects clearly indicate that added paramagnetic particles can affect the processes of spin evolution in RPs and RIPs. In particular, there are several examples demonstrating the influence of the third spin on the field dependences o f M F E in biradicals [3,5]. The mechanism o f the action o f the third spin on spin dynamics o f multispin systems (radical triad or tetrad) are partially related with the well-known relaxation effects (mainly due to the dipole-dipole interaction) [2] or to the manifestation of the electron spin exchange o f RP partners with an added spin. Note that the earlier available descriptions of experimental MFEs in multispin systems are qualitative.

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Section: Resultsmentioning

confidence: 85%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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