TY - JOUR

T1 - Reaction of Paramagnetic Synthon, Lithiated 4,4,5,5-Tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide, with Cyclic Aldonitrones of the Imidazole Series

AU - Tolstikov, Svyatoslav E.

AU - Tretyakov, Evgeny V.

AU - Gorbunov, Dmitry E.

AU - Zhurko, Irina F.

AU - Fedin, Matvey V.

AU - Romanenko, Galina V.

AU - Bogomyakov, Artem S.

AU - Gritsan, Nina P.

AU - Mazhukin, Dmitry G.

PY - 2016

Y1 - 2016

N2 - It was shown that dipole-stabilized paramagnetic carbanion lithiated 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide can be attached in a nucleophilic manner to either isolated or conjugated aldonitrones of the 2,5-dihydroimidazole 3-oxide and 2H-imidazole 1-oxide series to afford adducts the subsequent oxidation of which leads to polyfunctional mono- and diradicals. According to XRD, at least two polymorphic modifications can be formed during crystallization of the resulting paramagnetic compounds, and for each of them, geometric parameters of the molecules are similar. An EPR spectrum of the diradical in frozen toluene has a complicated lineshape, which can be fairly well reproduced by using X-ray diffraction structural analysis and the following set of parameters: D=14.9 mT, E=1.7 mT; tensor a(14N)=[0.260 0.260 1.625] mT, two equivalent tensors for the nitronyl nitroxide moiety a(14N)=[0.198 0.198 0.700] mT, and g≈2.007. According to our DFT and ab initio calculations, the intramolecular exchange in the diradical is very weak and most likely ferromagnetic.

AB - It was shown that dipole-stabilized paramagnetic carbanion lithiated 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide can be attached in a nucleophilic manner to either isolated or conjugated aldonitrones of the 2,5-dihydroimidazole 3-oxide and 2H-imidazole 1-oxide series to afford adducts the subsequent oxidation of which leads to polyfunctional mono- and diradicals. According to XRD, at least two polymorphic modifications can be formed during crystallization of the resulting paramagnetic compounds, and for each of them, geometric parameters of the molecules are similar. An EPR spectrum of the diradical in frozen toluene has a complicated lineshape, which can be fairly well reproduced by using X-ray diffraction structural analysis and the following set of parameters: D=14.9 mT, E=1.7 mT; tensor a(14N)=[0.260 0.260 1.625] mT, two equivalent tensors for the nitronyl nitroxide moiety a(14N)=[0.198 0.198 0.700] mT, and g≈2.007. According to our DFT and ab initio calculations, the intramolecular exchange in the diradical is very weak and most likely ferromagnetic.

KW - ab initio calculations

KW - density functional calculations

KW - diradicals

KW - EPR spectroscopy

KW - X-ray diffraction

UR - http://www.scopus.com/inward/record.url?scp=84982242933&partnerID=8YFLogxK

U2 - 10.1002/chem.201602049

DO - 10.1002/chem.201602049

M3 - Article

AN - SCOPUS:84982242933

VL - 22

SP - 14598

EP - 14604

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

SN - 0947-6539

IS - 41

ER -