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

A series
of water-bridged dinickel complexes of the general formula [Ni2(μ2-OH2)­(μ2-O2CtBu)2(O2CtBu)2(L)­(L′)] (L =
HO2CtBu, L′ = HO2CtBu (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(II) 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.