Specific features of the spin density distribution and magnetic properties in a series of pyrazolyl-substituted nitronyl nitroxides: a magnetochemical and quantum chemical study

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Specific features of the spin density distribution and magnetic properties in a series of pyrazolyl-substituted nitronyl nitroxides: a magnetochemical and quantum chemical study. / Letyagin, G. A.; Chernavin, P. A.; Maryunina, K. Yu et al.

In: Physical Chemistry Chemical Physics, 2025.

Research output: Contribution to journal › Article › peer-review

BibTeX

@article{ce58a6b5f7d54c009125c06cfb6e76ed,

title = "Specific features of the spin density distribution and magnetic properties in a series of pyrazolyl-substituted nitronyl nitroxides: a magnetochemical and quantum chemical study",

abstract = "A series of 2-(1-R-pyrazol-4-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl radicals (NN-4PzR) were synthesized and structurally and magnetochemically characterized. A comprehensive comparative crystallochemical analysis and quantum chemical calculations were carried out for a series of new and previously obtained radicals NN-4PzR and NN-5PzR [2-(1-R-pyrazol-5-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl]. It was shown that alteration of the spin label position drastically affects the molecular geometry and spin density distribution within the radicals. Planar molecules of NN-4PzH are conducive to π-π stacking interactions between pyrazole rings, which bring the radicals closer together and hence promote effective exchange interactions in the π stacks. In contrast, in NN-5PzR, substituent R of the pyrazole ring makes the formation of the planar structure infeasible due to steric effects, and exchange interactions arise mainly owing to short contacts between nitronyl nitroxide moieties. Thus, we proved that alteration of the spin label location is a powerful supramolecular tool and represents a mechanism of spin density variation in pyrazolyl-substituted NN-4PzR and NN-5PzR radicals.",

author = "Letyagin, {G. A.} and Chernavin, {P. A.} and Maryunina, {K. Yu} and Tolstikov, {S. E.} and Tretyakov, {E. V.} and Romanenko, {G. V.} and Bogomyakov, {A. S.}",

note = "The research was funded by the Russian Science Foundation (project No. 23-73-01224). We thank the Ministry of Science and Higher Education of the Russian Federation for granting access to the equipment. ",

year = "2025",

doi = "10.1039/d5cp01102g",

language = "English",

journal = "Physical Chemistry Chemical Physics",

issn = "1463-9076",

publisher = "Royal Society of Chemistry",

}

RIS

TY - JOUR

T1 - Specific features of the spin density distribution and magnetic properties in a series of pyrazolyl-substituted nitronyl nitroxides: a magnetochemical and quantum chemical study

AU - Letyagin, G. A.

AU - Chernavin, P. A.

AU - Maryunina, K. Yu

AU - Tolstikov, S. E.

AU - Tretyakov, E. V.

AU - Romanenko, G. V.

AU - Bogomyakov, A. S.

N1 - The research was funded by the Russian Science Foundation (project No. 23-73-01224). We thank the Ministry of Science and Higher Education of the Russian Federation for granting access to the equipment.

PY - 2025

Y1 - 2025

N2 - A series of 2-(1-R-pyrazol-4-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl radicals (NN-4PzR) were synthesized and structurally and magnetochemically characterized. A comprehensive comparative crystallochemical analysis and quantum chemical calculations were carried out for a series of new and previously obtained radicals NN-4PzR and NN-5PzR [2-(1-R-pyrazol-5-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl]. It was shown that alteration of the spin label position drastically affects the molecular geometry and spin density distribution within the radicals. Planar molecules of NN-4PzH are conducive to π-π stacking interactions between pyrazole rings, which bring the radicals closer together and hence promote effective exchange interactions in the π stacks. In contrast, in NN-5PzR, substituent R of the pyrazole ring makes the formation of the planar structure infeasible due to steric effects, and exchange interactions arise mainly owing to short contacts between nitronyl nitroxide moieties. Thus, we proved that alteration of the spin label location is a powerful supramolecular tool and represents a mechanism of spin density variation in pyrazolyl-substituted NN-4PzR and NN-5PzR radicals.

AB - A series of 2-(1-R-pyrazol-4-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl radicals (NN-4PzR) were synthesized and structurally and magnetochemically characterized. A comprehensive comparative crystallochemical analysis and quantum chemical calculations were carried out for a series of new and previously obtained radicals NN-4PzR and NN-5PzR [2-(1-R-pyrazol-5-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl]. It was shown that alteration of the spin label position drastically affects the molecular geometry and spin density distribution within the radicals. Planar molecules of NN-4PzH are conducive to π-π stacking interactions between pyrazole rings, which bring the radicals closer together and hence promote effective exchange interactions in the π stacks. In contrast, in NN-5PzR, substituent R of the pyrazole ring makes the formation of the planar structure infeasible due to steric effects, and exchange interactions arise mainly owing to short contacts between nitronyl nitroxide moieties. Thus, we proved that alteration of the spin label location is a powerful supramolecular tool and represents a mechanism of spin density variation in pyrazolyl-substituted NN-4PzR and NN-5PzR radicals.

UR - https://www.mendeley.com/catalogue/3f3a9886-9477-3b50-880d-719258bcce17/

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-105006894485&origin=inward&txGid=b32345c875934197fbd296cbbfb55d09

U2 - 10.1039/d5cp01102g

DO - 10.1039/d5cp01102g

M3 - Article

C2 - 40434806

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

ER -

ID: 67456008