The first example of erbium triple-stranded helicates displaying SMM behaviour

A series of isostructural C-3-symmetrical triple stranded dinuclear lanthanide [Ln(2)L(3)](NO3)(3) molecules have been synthesized using subcomponent self-assembly of Ln(NO3)(3) with 2-(methylhydrazino) benzimid-azole and 4-tert-butyl-2,6-diformylphenol, where Ln = Tb (1), Dy (2), Ho (3), Er (4), Tm (5), and Yb (6). The temperature dependent and field dependent magnetic properties of 1-6 were modeled using the van Vleck approximation including the crystal field term H-CF, the super-exchange term H-SE and the Zeeman term H-ZE. Ferromagnetic interactions were found in 1, 2, 4 and 6, while antiferromagnetic interactions were found in 3 and 5. The erbium analogue reveals field induced SMM behaviour.