Long-distance ferromagnetic coupling through spin polarization in a linear heterotrinuclear iron(iii)–copper(ii)–iron(iii) complex derived from 5-ferrocenyl-2-aminotropone

Abstract

A novel hetrotrinuclear complex composed of two ferrocenium-ion moieties and copper complex of 2-aminotropones showed relatively strong intramolecular ferromagnetic coupling in the solid states owing to spin polarization mechanism.

η5‐Cyclopentadienyliron(II)–[14]Triphyrin(2.1.1) Sandwich Compounds: Synthesis, Characterization, and Stable Redox Interconversion

“…The structure determined contained [CF 3 SO 3 ] 2 Ag] − as a counteranion. The Cp ring is coordinated to Fe III ion through the five carbon atoms, with the distance of 1.723 Å, which is longer than that of 2 a , suggesting that the additional positive charge in 2 a + is mostly localized on the formal Fe III atom 17…”

Structural, electronic and magnetic properties of Cu(ii) complexes of 2-substituted tropones bearing a ferrocenyl group at 5-position

“…On the other hand, the ESR spectrum of 3 in THF showed the coupling due to nitrogen ligands (g ^= 2.03 (a N = 1.0 mT), g = 2.13 (a Cu = 7.9 mT)). 16 In sharp contrast, the signal from the Cu(II) part almost disappeared for 3 2+ in acetonitrile at room temperature. The disappearance of the signal is considered to be caused by the intramolecular exchange interaction between the Cu(II) and Fe(III) ions, because the ESR signal of ferrocenium ions can be observed only below ca.…”

“…To prepare a reference compound, one-electron oxidations of these ligands were also attempted and only 5 gave isolable product (5 + ClO 4 -) by the reaction with Fe(ClO 4 ) 3 owing to the presence of a more electrondonating amino group. 16 Tropones 4 and 5 containing no acidic proton in the ligand parts form the Cu(II) complexes 1 and 2, respectively, when treated with Cu(OTf) 2 . Single crystals of 1 and 2 were obtained by slow diffusion of diisopropyl or diethyl ether into the reaction mixture of ligands 4 or 5 with Cu(OTf) 2 in acetone (Scheme 4).…”

“…The molecular structures of Cu(II) complexes 1, 2, 3 16 and 3 2+ (PF 6 -) 2 16 as well as tropone ligands 4-7 and 5 + ClO 4 -16 were determined by X-ray crystallography. The molecular structures of the Cu(II) complexes are shown in Fig.…”

η5‐Cyclopentadienyliron(II)–[14]Triphyrin(2.1.1) Sandwich Compounds: Synthesis, Characterization, and Stable Redox Interconversion

“…Interestingly, the TFA titration of 2 a showed a similar UV/Vis spectral change with electrochemical oxidation. [17] In summary, we have successfully synthesized and characterized the unique sandwich iron(II) compounds 2 a and 2 b prepared from the corresponding free-base [14]triphyrin-(2.1.1) 1 a and 1 b with [{Fe(CO) 2 (Cp)} 2 ]. The NMR and HR-ESI-MS spectra of 2 a in the presence of TFA showed the same spectrum to that of 2 a + (Supporting Information, Figures S14 and S19).…”