Hydrothermal synthesis, crystal structure and characterization of a new hexanuclear cobalt(II) complex comprised of octahedral and tetrahedral cobalt ions

Reaction of Co(II) with phenylcinnamic acid and sodium hydroxide under hydrothermal conditions yields a new hexanuclear Co(II) complex, [Co-6(OH)(2)(L)(10)] (L = phenylcinnamate). [Co-6(OH)(2)(L)(10)] consists of two edge-sharing octahedral {CoO6} and four tetrahedral {CoO4} units linked through mu-carboxylate ligands and mu-hydroxide ions. The magnetic moment shows a large decrease from 300 to 25 K which amounts to antiferromagnetic coupling between cobalt ions in octahedral and tetrahedral sites leading to an s = 3 ground-state at low temperatures. (C) 2003 Elsevier Science Ltd. All rights reserved.