Anion-dependent assembly of Dy complexes: structures and magnetic behaviors

Abstract

The self-assembly of 2-aldehyde-8-hydroxyquinoline, histamine dihydrochloride and LnX₃·6H₂O (X⁻ = OAc⁻, NO₃⁻ and ClO₄⁻) affords a series of lanthanide complexes, namely Nd₃(nma)₂(OAc)₇·3CH₃OH·0.5H₂O (1a), Ln₃(nma)₂(OAc)₇·2CH₃OH [Ln = Tb (1b) and Dy (1c)], [Ln(nma)(NO₃)₂(DMSO)]·CH₃OH [Ln = Nd (2a), Tb (2b), Dy (2c) and Er (2d)] and [Dy(nma)₂]·ClO₄·0.5CH₃OH (3) (Hnma = N-(2-(8-hydroxylquinolinyl)methane(2-(4-imidazolyl)ethanamine))). It is noted that the formation and structures of 1–3 are anion-dependent, where diverse coordination modes are detected for acetates in trinuclear 1 as compared to the single coordination mode for nitrates in mononuclear 2. In the case of 3, the Dy³⁺ ion is completely encapsulated by two ligands with an uncoordinated perchlorate anion balancing the charge. Magnetic measurement shows that the Dy complexes of 1c, 2c and 3 exhibit slow relaxations under zero dc field. It is noted that single-molecule magnet behavior is obtained for 2c and 3 under an applied dc field of 2000 Oe.