Structure and Magnetic Properties of a Hydroxo-Bridged Copper(II) Distorted Cubane Stabilized via Supramolecular Hydrogen Bonding with an Ionic Hexafluoroacetylacetonate

Tetranuclear [CuII4(OH)4(aib)4)](hfac)4 (1; aib = 2-methyl-2-amino-4-iminopentane; hfac = hexafluoroacetylacetonate) forms from the reaction of aqueous ammonia and Cu(hfac)2·2H2O in acetone. The structure of 1 reveals that four noncoordinating hfac- counterions stabilize the distorted cubane complex via multiple H-bonding contacts. Magnetic susceptibility studies reveal that cubane-like 1 is best described as a pair of independent antiferromagnetically coupled dimers with g = 2.10 and J/kB = −298 K (207 cm-1) (H = −2JS1·S2).