TY - JOUR

T1 - A crystallographic study of a novel tetrazolyl-substituted nitronyl nitroxide radical

AU - Romanov, Vasily E.

AU - Bagryanskaya, Irina Yu

AU - Gorbunov, Dmitry E.

AU - Gritsan, Nina P.

AU - Zaytseva, Elena V.

AU - Luneau, Dominique

AU - Tretyakov, Evgeny V.

N1 - Publisher Copyright: © 2018 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2018/9/1

Y1 - 2018/9/1

N2 - Spin-labelled compounds are widely used in chemistry, physics, biology, and material sciences, but the directed synthesis of some functionalized organic radicals is still a challenge. We succeeded in the preparation of a tetrazolyl-substituted nitronyl nitroxide radical in pure crystalline form. According to the single-crystal X-ray data, intra-(NH… O, 2.43 Å) and inter-molecular hydrogen bonds (NH… O, 1.91 Å) are formed between NH groups of the tetrazole cycles and O atoms of the paramagnetic moieties. The intermolecular H-bonds connect the molecules forming chains along the a-axis. Moreover, there are short intermolecular contacts between the O atoms (3.096 Å) and between the O and C atoms (3.096 Å) of the nitronyl nitroxide moieties within the chain. The spin-unrestricted broken-symmetry calculations performed at the BS-UB3LYP/def2-TZVP level of theory predicted a sufficient ferromagnetic interaction (J ≈ 20 cm–1) between the adjacent radicals inside the chain, but a weak antiferromagnetic interaction (−J ≤0.2 cm−1) between the nearest radicals belonging to the different chains. Thus, a rare case when stable radicals, the tetrazolyl-substituted nitronyl nitroxides, are ordered into ferromagnetic chains was revealed; an investigation of the magneto-structural correlations inherent in the nitroxide radical will demand a special experiment in the sub-Kelvin regime.

AB - Spin-labelled compounds are widely used in chemistry, physics, biology, and material sciences, but the directed synthesis of some functionalized organic radicals is still a challenge. We succeeded in the preparation of a tetrazolyl-substituted nitronyl nitroxide radical in pure crystalline form. According to the single-crystal X-ray data, intra-(NH… O, 2.43 Å) and inter-molecular hydrogen bonds (NH… O, 1.91 Å) are formed between NH groups of the tetrazole cycles and O atoms of the paramagnetic moieties. The intermolecular H-bonds connect the molecules forming chains along the a-axis. Moreover, there are short intermolecular contacts between the O atoms (3.096 Å) and between the O and C atoms (3.096 Å) of the nitronyl nitroxide moieties within the chain. The spin-unrestricted broken-symmetry calculations performed at the BS-UB3LYP/def2-TZVP level of theory predicted a sufficient ferromagnetic interaction (J ≈ 20 cm–1) between the adjacent radicals inside the chain, but a weak antiferromagnetic interaction (−J ≤0.2 cm−1) between the nearest radicals belonging to the different chains. Thus, a rare case when stable radicals, the tetrazolyl-substituted nitronyl nitroxides, are ordered into ferromagnetic chains was revealed; an investigation of the magneto-structural correlations inherent in the nitroxide radical will demand a special experiment in the sub-Kelvin regime.

KW - Crystal structure

KW - Density functional theory

KW - Exchange interaction

KW - Hydrogen bonding

KW - Nitronyl nitroxides

KW - Stable radicals

KW - Tetrazoles

KW - MANGANESE(II)

KW - nitronyl nitroxides

KW - MOLECULE

KW - COMPLEXES

KW - stable radicals

KW - exchange interaction

KW - NEUTRON-DIFFRACTION

KW - 3-OXIDE

KW - SALTS

KW - DENSITY

KW - TRANSITION

KW - hydrogen bonding

KW - tetrazoles

KW - density functional theory

KW - crystal structure

KW - MAGNETIC-PROPERTIES

KW - EXCHANGE

UR - http://www.scopus.com/inward/record.url?scp=85052619978&partnerID=8YFLogxK

U2 - 10.3390/cryst8090334

DO - 10.3390/cryst8090334

M3 - Article

AN - SCOPUS:85052619978

VL - 8

JO - Crystals

JF - Crystals

SN - 2073-4352

IS - 9

M1 - 334

ER -