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(Pyrrole-2,5-diyl)-bis(nitronyl nitroxide) and-bis(iminonitroxide) : Specific features of the synthesis, structure, and magnetic properties. / Tretyakov, Evgeny; Tkacheva, Anastasia; Romanenko, Galina et al.
In: Molecules, Vol. 25, No. 7, 1503, 26.03.2020.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - (Pyrrole-2,5-diyl)-bis(nitronyl nitroxide) and-bis(iminonitroxide)
T2 - Specific features of the synthesis, structure, and magnetic properties
AU - Tretyakov, Evgeny
AU - Tkacheva, Anastasia
AU - Romanenko, Galina
AU - Bogomyakov, Artem
AU - Stass, Dmitri
AU - Maryasov, Alexander
AU - Zueva, Ekaterina
AU - Trofimov, Boris
AU - Ovcharenko, Victor
PY - 2020/3/26
Y1 - 2020/3/26
N2 - In contrast to diradicals connected by alternant hydrocarbons, only a few studies have addressed diradicals connected by nonalternant hydrocarbons and their heteroatom derivatives. Here, the synthesis, structure, and magnetic properties of pyrrole-2,5-diyl-linked bis(nitronyl nitroxide) and bis(iminonitroxide) diradicals are described. The diradicals show characteristic electron spin resonance spectra in dilute glassy solutions, from which conclusions about the presence of distinct conformations, their symmetry, and interspin distance were made. X-ray diffraction analysis of the diradicals revealed that paramagnetic moieties lie in the plane of the pyrrole ring, because of the formation of an intramolecular hydrogen bond, ONO . . . H−N, with O . . . H distances of 2.15-2.23 Å. The N-O groups participating in the formation of H-bonds have greater bond lengths (~1.29 Å) as compared with nonparticipating groups (~1.27 Å). The nitronyl nitroxide and iminonitroxide diradicals showed an intramolecular antiferromagnetic interaction, with J = −77.3 and −22.2 cm−1, respectively (H = −2JS1·S2).
AB - In contrast to diradicals connected by alternant hydrocarbons, only a few studies have addressed diradicals connected by nonalternant hydrocarbons and their heteroatom derivatives. Here, the synthesis, structure, and magnetic properties of pyrrole-2,5-diyl-linked bis(nitronyl nitroxide) and bis(iminonitroxide) diradicals are described. The diradicals show characteristic electron spin resonance spectra in dilute glassy solutions, from which conclusions about the presence of distinct conformations, their symmetry, and interspin distance were made. X-ray diffraction analysis of the diradicals revealed that paramagnetic moieties lie in the plane of the pyrrole ring, because of the formation of an intramolecular hydrogen bond, ONO . . . H−N, with O . . . H distances of 2.15-2.23 Å. The N-O groups participating in the formation of H-bonds have greater bond lengths (~1.29 Å) as compared with nonparticipating groups (~1.27 Å). The nitronyl nitroxide and iminonitroxide diradicals showed an intramolecular antiferromagnetic interaction, with J = −77.3 and −22.2 cm−1, respectively (H = −2JS1·S2).
KW - Diradicals
KW - Iminonitroxides
KW - Magnetochemistry
KW - Nitronyl nitroxides
KW - Pyrrole derivatives
KW - Quantum-chemical calculations
KW - diradicals
KW - nitronyl nitroxides
KW - magnetochemistry
KW - NITRONYL-NITROXIDE
KW - STATE
KW - DISJOINT
KW - DIMERS
KW - THIOPHENE
KW - quantum-chemical calculations
KW - DIRADICALS
KW - pyrrole derivatives
KW - iminonitroxides
UR - http://www.scopus.com/inward/record.url?scp=85082593531&partnerID=8YFLogxK
U2 - 10.3390/molecules25071503
DO - 10.3390/molecules25071503
M3 - Article
C2 - 32224961
AN - SCOPUS:85082593531
VL - 25
JO - Molecules
JF - Molecules
SN - 1420-3049
IS - 7
M1 - 1503
ER -
ID: 23948698