Stabilisation of heterobimetallic networks by crown ethers and hydrogen-bonding in [Ni(H2O)6][Cu3Cl8(H2O)2] · (15-crown-5)2 · 2H2O: Structure and magnetism

[Ni(H2O)6][Cu3Cl8(H2O)2] · (15-crown-5)2 · 2H2O can be conveniently prepared by the interaction of NiCl2 · 6H2O, CuCl2 · 2H2O and 15-crown-5 in water. The X-ray crystal structure reveals an ionic complex involved in a hydrogen-bonded two dimensional network with the [Ni(H2O)6]2+ and [Cu3Cl8(H2O)2]2− ions sandwiched between the 15-crown-5 macrocycles. The magnetic susceptibility data (4–300 K) and magnetisation isotherms (2–5.5 K; 0–5 T) are best interpreted in terms of intra-trimer ferromagnetic coupling within the [Cu3Cl8(H2O)2]2− moieties, with J ∼ 6 cm−1, and antiferromagnetic coupling between the trimers, the latter mediated by H-bonding pathways. Comparisons are made to other reported quaternary ammonium salts of [Cu3Cl8]2− and [Cu3Cl12]6−, most of which display structures that involve close stacking of such Cu(II) trimers, rather than being of the present isolated, albeit H-bonded, types.

Graphical abstract[Ni(H2O)6][Cu3Cl8(H2O)2] · (15-crown-5)2 · 2H2O can be conveniently prepared by the interaction of NiCl2 · 6H2O, CuCl2 · 2H2O and 15-crown-5 in water and is found to display intra-trimer ferromagnetic coupling and inter-trimer antiferromagnetic interactions, the latter possibly occurring via the H-bonded [Ni(H2O)6]2+ cations.Figure optionsDownload full-size imageDownload as PowerPoint slide