Spin catalysis: three-spin model

Бучаченко, А. Л.; Berdinsky, Vitaly L.

doi:10.1016/0009-2614(95)00726-k

Cited by 22 publications

(22 citation statements)

References 4 publications

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“…The encounter pair of freely diffusing peroxy radicals either recombines resulting unstable tetraoxide RO 4 radicals. Due to MIE, which differentiates the rates of spin conversion, the recombination probability of peroxy radicals with terminal 17 O atoms is higher than that of radicals with 16 O and 18 O atoms. As a result, the tetraoxide and, consequently, the recovered oxygen is enriched with 17 O, while the hydroperoxide molecules are enriched with 16 O and 18 O.…”

Section: Magnetic Isotope Effectmentioning

confidence: 99%

“…Due to MIE, which differentiates the rates of spin conversion, the recombination probability of peroxy radicals with terminal 17 O atoms is higher than that of radicals with 16 O and 18 O atoms. As a result, the tetraoxide and, consequently, the recovered oxygen is enriched with 17 O, while the hydroperoxide molecules are enriched with 16 O and 18 O. Figure 3 demonstrates isotope enrichment of molecular oxygen as a function of oxygen conversion; the higher chemical conversion the larger number of recovered oxygen molecules and the higher isotope enrichment.…”

Section: Magnetic Isotope Effectmentioning

confidence: 99%

“…Figure 3 demonstrates isotope enrichment of molecular oxygen as a function of oxygen conversion; the higher chemical conversion the larger number of recovered oxygen molecules and the higher isotope enrichment. It is impressive that MIE-induced 17 O isotope enrichment strongly exceeds 18 O enrichment induced by CIE. Figure 4 shows the chain length effect on the isotope separation which evidences in favor of the mechanism of isotope selection: the shorter the chain length, the more spin-selective termination reactions and, therefore, the higher isotope sorting. Figure 5 demonstrates the impressive distinction of the temperature behavior of isotope fractionation induced by MIE and CIE.…”

Section: Magnetic Isotope Effectmentioning

confidence: 99%

“…MIE in quartet-doublet spin conversion selects magnetic 17 O nuclei into peroxy radicals, resulting in impoverishment of the remaining molecular oxygen with 17 O. In contrast, oxygen molecules with 18 O react slower than those with 16 O, resulting in CIE-induced enrichment of molecular oxygen with 18 O.…”

Section: Magnetic Isotope Effectmentioning

confidence: 99%

“…The theory of spin catalysis in three-spin system was developed in 1995 [17]. Three spins form 8 spin states; four of them with spin 3 / 4 (quartet states) are chemically inert, nonreactive, and do not expose to spin catalysis.…”

Section: Fig 14mentioning

confidence: 99%

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Recent advances in spin chemistry

Бучаченко

2000

Pure and Applied Chemistry

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Abstract:The great success in controlling chemical reactivity by spin manipulation was achieved in the last decade, and many remarkable spin and magnetic phenomena have been discovered. Among those discoveries, the most chemically important highlights are magnetic isotope effect, spin catalysis, and single-spin tunneling spectroscopy. This paper summarizes recent advances in these new and hot areas of modern chemistry. GENERAL OUTLOOK OF SPIN CHEMISTRYSpin chemistry as a new land and hot area in modern chemistry is based on the universal and fundamental principle-all chemical reactions are spin selective. They allowed only for those spin states of products whose total electron spin is identical to that of reagents. The reactions are forbidden if they require a change of spin.Some typical examples of spin-selective reactions are given below. The recombination of radicals into the diamagnetic molecule is allowed from singlet state of the reaction precursor, radical pair:Triplet state is strictly forbidden for the reaction, so that triplet pair either dissociates to free radicals, or experiences spin conversion (shown by dashed arrow), which transforms nonreactive triplet state into the chemically reactive singlet state.Chemical addition of radical to triplet molecule (oxygen, for instance), as well as physical quenching of excited triplet molecule by radical, takes place only in doublet state:Quartet spin state is forbidden to react and quartet-doublet spin conversion is required to switch over the reaction channel. Again, spin selectivity is controlled by competition between the dissociation of the quartet pair on the starting reagents and spin transformation of the pair into the reactive doublet state.In the reaction of two triplets (recombination of carbenes, delayed fluorescence from the fusion of two excited triplet molecules, etc.) only one of the nine spin states is open to react: *Plenary lecture presented at the 15

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Section: Magnetic Isotope Effectmentioning

confidence: 99%

Section: Magnetic Isotope Effectmentioning

confidence: 99%

Section: Magnetic Isotope Effectmentioning

confidence: 99%

Section: Magnetic Isotope Effectmentioning

confidence: 99%

Section: Fig 14mentioning

confidence: 99%

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Recent advances in spin chemistry

Бучаченко

2000

Pure and Applied Chemistry

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Photochemically Induced Dynamic Nuclear Polarization

Goez

1997

Advances in Photochemistry

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Paramagnetic spin catalysis of a radical recombination reaction

Минаев

1996

Mol Eng

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Recombination of the triplet state radical pair consisting of two hydrogen atoms catalysed by molecular oxygen is considered as a simulating example of a paramagnetic-exchange catalytic process. Intermolecular exchange interaction in the collision complex between the Hz and Oa molecules is calculated a6 initio in STOdG and 6-31 G* basis sets with complete active space configuration interaction. Calculations are done at a fixed O-H distance ( = 3 A), scanning the H-H bond length from 0.6 till 12 8, at the linear geometry of collision.

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Spin catalysis: three-spin model

Cited by 22 publications

References 4 publications

Recent advances in spin chemistry

Recent advances in spin chemistry

Photochemically Induced Dynamic Nuclear Polarization

Paramagnetic spin catalysis of a radical recombination reaction

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