Structural and magnetic properties of polynuclear oximate copper complexes with different topologies

Two new copper(II) complexes containing the methyl(2-pyridyl)ketone oxime ligand (mpkoH) [Cu-3(OH)(ClO4)(2)(mpko)(3)]center dot CH3OH (1) and [Cu(ClO4)(mpko)(mpkoH)](n) (2) have been prepared from Cu(ClO4)(2) and mpkoH in different metal-to-ligand molar ratios. In addition, the compound [Cu{(mpko)(2)BF2}(H2O)](BF4) (3) [(mpko)2BF(2) is the fluoroboration product of the oxime] has been obtained when replacing Cu(ClO4)(2) by Cu(BF4)(2). Compound 1 is an isolated triangle with a {Cu-3(mu(3)-OH)}(5+) core, whereas 2 is a chain of Cu-II ions linked by anionic mpko(-) bridges. 1 exhibits strong antiferromagnetic competing interactions, as well as antisymmetric exchange. On the other hand, very weak ferromagnetic interactions are found in 2. The magnetic properties of these compounds have been analyzed by magnetic measurements and EPR spectra. (C) 2017 Elsevier Ltd. All rights reserved.