Anion-controlled assembly of a series of heterometallic 3d–4f compounds with 0D cluster, 1D chain, 2D network and 3D frameworks

Abstract

A series of heterometallic 3d–4f compounds, formulated as [Ln₂Ni₂(dcta)₂(H₂O)₈(NO₃)₂]·8H₂O (Ln = Nd (1); Ln = Dy (2)); {[DyNi(dcta)(H₂O)₆]·Cl·(H₂O)₂}_n (3); {[LnNi(dcta)(H₂O)₆]·(ClO₄)·(H₂O)₃}_n (Ln = La (4); Ln = Nd (5)); {[Gd₁₂Ni₁₂(dcta)₁₂(H₂O)₂₄]·[Ni(H₂O)₆]₃·(ClO₄)₁₈·(H₂O)₈₀}_n (6) and {[La₁₂Ni₁₂(dcta)₁₂(H₂O)₆₀]·[Ni(H₂O)₆]₃·(ClO₄)₁₈·(H₂O)₃₀}_n (7), (H₄dcta = trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid), have been obtained through a metalloligand strategy. Structural analysis reveals that [Ni(dcta)]²⁻ acts as a bidentate metalloligand in 1–3, tridentate metalloligand in 4 and 5, and tetradentate metalloligand in 6 and 7. These compounds can be divided into four types according to the dimensionality of the structures. Compounds 1 and 2 are 0D tetranuclear clusters comprised of symmetric [LnNi(dcta)]₂ 12-membered rings, compound 3 is a 1D chain which is reinforced by hydrogen bonds. Compounds 4 and 5 possess an infinite 2D layer structure with a 6³-hcb topology, and compounds 6 and 7 are two 3D frameworks constructed by face-sharing Keplerate-type metal–organic polyhedra. It is interesting that different anions lead to different topology structures. The magnetic properties and thermal stabilities of them are also studied.