Synthesis, structure and magnetic study of a novel mixed-valent Co II10Co III4 shield constructed by mixed pyridine-alcoholate ligands

Abstract

A novel tetradecanuclear mixed-valent cobalt cluster, formulated as [Co II10Co III4(OH) 2O 6(hmp) 10(pdm) 4(CH 3OH) 2]·5H 2O (1), was obtained using mixed ligands of 2-(hydroxymethyl)pyridine (hmpH) and 2,6-pyridinedimethanol (pdmH 2). The cobalt ions in 1 are connected by ten chelating hmp - ligands, four tris-chelating pdm 2- ligands and six μ 3-oxide/ hydroxide anions, forming a unique shield-like planar structure that is rarely observed for Co-based clusters. Compound 1 displays slight frequency dependence at static zero field below 4.5 K, suggesting that it might be a single molecule magnet (SMM). © The Royal Society of Chemistry 2012.