Novel Copper(II) Complexes with Dipinodiazafluorene Ligands: Synthesis, Structure, Magnetic and Catalytic Properties

Fomenko, I.S.; Afewerki, M.; Gongola, M.I.; Vasilyev, E.S.; Shul’pina, L.S.; Ikonnikov, N.S.; Shul’pin, G.B.; Samsonenko Yanshole, V.V.; Nadolinny, V.A.; Lavrov, A.N.; Tkachev, A.V.; Gushchin, A.L.

Авторы: Fomenko I.S., Afewerki M., Gongola M.I., Vasilyev E.S., Shul’pina L.S., Ikonnikov N.S., Shul’pin G.B., Samsonenko Yanshole V.V.D.G, Nadolinny V.A., Lavrov A.N., Tkachev A.V., Gushchin A.L.
Журнал: Molecules
Том: 27
Номер: 13
Год издания: 2022
Издательство: MDPI
Местоположение издательства: Basel, Switzerland
Номер статьи: 4072
DOI: 10.3390/molecules27134072
Аннотация: The reactions of CuX2(X = Cl, Br) with dipinodiazafluorenes yielded four new complexes[CuX2L1]2(X = Cl (1), Br (2), L1 = (1R,3R,8R,10R)-2,2,9,9-Tetramethyl-3,4,7,8,9,10-hexahydro-1H1,3:8,10-dimethanocyclopenta [1,2-b:5,4-b’]diquinolin-12(2H)-one) and [(CuX2)2L2]n (X = Cl (3), Br (4),L2 = (1R,3R,8R,10R,1’R,3’R,8’R,10’R)-2,2,2’,2’,9,9,9’,9’-Octamethyl-1,1’,2,2’,3,3’,4,4’,7,7’,8,8’,9,9’,10,10’-hexadecahydro-1,3:1’,3’:8,10:8’,10’-tetramethano-12,12’-bi(cyclopenta [1,2-b:5,4-b’]diquinolinylidene).The complexes were characterized by IR and EPR spectroscopy, HR-ESI-MS and elemental analysis.The crystal structures of compounds 1, 2 and 4 were determined by X-ray diffraction (XRD) analysis.Complexes 1–2 have a monomeric structure, while complex 4 has a polymeric structure due to additional coordinating N,N sites in L2. All complexes contain a binuclear fragment {Cu2(µ-X)2×2} (X = Cl,Br) in their structures. Each copper atom has a distorted square-pyramidal coordination environmentformed by two nitrogen atoms and three halogen atoms. The Cu-Nax distance is elongated comparedto Cu-Neq. The EPR spectra of compounds 1–4 in CH3CN confirm their paramagnetic nature dueto the d9electronic configuration of the copper(II) ion. The magnetic properties of all compoundswere studied by the method of static magnetic susceptibility. For complexes 1 and 2, the effectivemagnetic moments are µeff ≈ 1.87 and 1.83 µB (per each Cu2+ ion), respectively, in the temperaturerange 50–300 K, which are close to the theoretical spin value (1.73 µB). Ferromagnetic exchangeinteractions between Cu(II) ions inside {Cu2(µ-X)2X2} (X = Cl, Br) dimers (J/kB ≈ 25 and 31 K for 1and 2, respectively) or between dimers (θ0 ≈ 0.30 and 0.47 K for 1 and 2, respectively) were found atlow temperatures. For compounds 3 and 4, the magnetic susceptibility is well described by the Curie–Weiss law in the temperature range 1.77–300 K with µeff ≈ 1.72 and 1.70 µB for 3 and 4, respectively,and weak antiferromagnetic interactions (θ ≈ −0.4 K for 3 and −0.65 K for 4). Complexes 1–4 exhibithigh catalytic activity in the oxidation of alkanes and alcohols with peroxides. The maximum yield ofcyclohexane oxidation products reached 50% (complex 3). Based on the data on the study of regioand bond-selectivity, it was concluded that hydroxyl radicals play a decisive role in the oxidationreaction. The initial products in reactions with alkanes are alkyl hydroperoxides.
Добавил в систему: Шульпин Георгий Борисович

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Novel Copper(II) Complexes with Dipinodiazafluorene Ligands: Synthesis, Structure, Magnetic and Catalytic Propertiesстатья

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