Details

Autor(en) / Beteiligte

• Scheurer, Andreas
• Korzekwa, Jana
• Nakajima, Takayuki
• Hampel, Frank
• Buling, Anna
• Derks, Christine
• Neumann, Manfred
• Joly, Loïc
• Petukhov, Konstantin
• Gieb, Klaus
• Müller, Paul
• Kuepper, Karsten
• Meyer, Karsten

Titel

Synthesis, Magnetic Properties, and X-ray Spectroscopy of Divalent Cobalt(II) and Nickel(II) Cubanes [MII4(HL2)4(OAc)4]

Ist Teil von

• European journal of inorganic chemistry, 2015-04, Vol.2015 (11), p.1872-1901

Ort / Verlag

Weinheim: WILEY-VCH Verlag

Erscheinungsjahr

2015

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• Under anaerobic conditions, the reactions of cobalt(II) and nickel(II) acetate tetrahydrate with 2,6‐pyridinedimethanol (H2L2, 3) in anhydrous acetonitrile afforded two tetranuclear metal(II) complexes [MII4(HL2)4(OAc)4] (4; MII = Co2+, Ni2+) with a [M4(μ3‐O)4]4+ cubane core. X‐ray structural analyses revealed that both MII cubanes 4a·2CH3OH and 4b·2CH3OH are isostructural and crystallize in the tetragonal space group I41/acd with eight molecules in the unit cell. In the solid state, the orientation of the cubane cores of 4 and the formation of a 3D framework were controlled by π–π interactions as well as intra‐ and intermolecular O–H···O hydrogen bonds. Variable‐temperature magnetic susceptibility measurements revealed that the cubanes 4 show a ferrimagnetic coupling scheme that leads to a diamagnetic ground state for both complexes. Core‐level X‐ray photoelectron spectroscopy confirmed that the Co and Ni ions in 4a and 4b are in a divalent state. X‐ray magnetic circular dichroism was performed to extract the spin and orbital contributions to the Co and Ni magnetic moments. We compared the experimental results of the local electronic structures around the Co2+ ions in 4a and the Ni2+ ions in 4b with charge‐transfer multiplet simulations. Starting from 2,6‐pyridinedimethanol (H2L2, 3) and metal(II) acetate tetrahydrates, divalent CoII and NiII cubanes [MII4(HL2)4(OAc)4] (4) have been synthesized through self‐organization. In addition to standard methods (e.g., IR, MS, X‐ray analysis), complexes 4 were also characterized by magnetometry and X‐ray spectroscopic techniques, including XPS, XAS, and XMCD.