On the Possibility of Magneto-Structural Correlations: Detailed Studies of Dinickel Carboxylate Complexes

Abstract

Bu, L = HO 2 C t Bu (1), pyridine (2), 3-methylpyridine (4); L = L = pyridine (3), 3-methylpyridine (5)) has been synthesized and structurally characterized by X-ray crystallography. The magnetic properties have been probed by magnetometry and EPR spectroscopy, and detailed measurements show that the axial zero-field splitting, D, of the nickel( ) ions is on the same order as the isotropic exchange interaction, J, between the nickel sites. The isotropic exchange interaction can be related to the angle between the nickel centers and the bridging water molecule, while the magnitude of D can be related to the coordination sphere at the nickel sites.

Multielectron oxidation in a ferromagnetically coupled dinickel(ii) triple mesocate

“…The Q-band EPR spectrum at 8 K of 1b in acetonitrile solution shows a complicated spectral pattern similar to that reported in a previous paper for [Ni 2 (m 2 -OH 2 )(m 2 -O 2 CBu) 2 (O 2 CBu) 2 (py)(3-Mepy)] 11 (py = pyridine and 3-Mepy = 3-methylpyridine) (see Fig. Up to now, all our attempts to characterize the quadruple oxidized dinickel(IV) species obtained either by chemical or electrochemical oxidations were unsuccessful, probably because of its partial decomposition under our experimental conditions.…”

Systematic Study of a Family of Butterfly-Like {M2Ln2} Molecular Magnets (M = MgII, MnIII, CoII, NiII, and CuII; Ln = YIII, GdIII, TbIII, DyIII, HoIII, and ErIII)

“…An interesting M β (H) profile is observed (inset in Figure 2b), with exponentiallike behavior and higher magnetization values observed at 4 than at 2 K, suggesting that paramagnetic excited states are close to an S = 0 ground state. Modeling the magnetic behavior of {Ni 2 Y 2 } requires an additional term in the Hamiltonian because the zerofield splitting of the Ni(II) ions (D Ni ) is likely to be of the same order as the weak exchange interaction; 26 (Figure S2a, Supporting Information). Such behavior is expected from the orbitally degenerate 4 T 1g ground term of six-coordinate Co(II), with a well-isolated spin− orbit doublet ground state.…”

Polarized Neutron Diffraction as a Tool for Mapping Molecular Magnetic Anisotropy: Local Susceptibility Tensors in CoII Complexes

“…Even for dimers, not to mention compounds with highern uclearity,d etermination of the individual g and D anisotropy tensors by using EPR is rare and subjectt oe ffective models. [31,32] NMR spectroscopy was also recently used to determine the magnetic susceptibili-ty tensoro fad ouble-decker Tb-phthalocyanine SMM, but in solution. [33] To makes ignificant progress in the design of molecules with strongm agnetic anisotropy,i ti se ssential to establish correlations experimentally between the local magnetic anisotropy tensora nd the local structure around the magnetic ions.…”