Synthesis, structures, and single-molecule magnet behaviour of high-nuclearity nickel(II) dicubane-type complexes with pyridyl-alcohol-ligands

Sophie Hameury (1) , Laure Kayser (1) , Roberto Pattacini (1) , Patrick Rosa (2) , Anne-Laure Barra (3) , Pierre Braunstein (1)

1 Institut de Chimie de Strasbourg
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
3 LNCMI-G - Laboratoire national des champs magnétiques intenses - Grenoble

The condensation reaction between two chemically different tetranuclear cubane-like clusters [Ni(μ3-Cl)(Cl)(HL)]4 (1; HL=2-methyl-1-(pyridin-2-yl)propan-2-ol) and [Ni(μ3-OH)(Cl)(HL)]4 (2) provides new access to higher nuclearity complexes, as shown with the synthesis of the octanuclear complex [Ni8(μ3-Cl)3(μ3-OH)5(μ-Cl)2Cl6(HL)7] (3). In one instance, we also isolated the heptanuclear complex [Ni7(μ3-Cl)2(μ3-OH)6Cl4(H2O)2(HL)6]Cl2 (4). Magnetic properties measured by superconducting quantum interference device (SQUID) susceptometry evidenced S=8 and S=5 ground states for complexes 3 and 4, respectively. In particular, alternating current (ac) susceptometry evidenced slow relaxation of the magnetisation for complex 3, and suggests a similar behaviour at sub-kelvin temperatures for complex 4.

Mots clés: cluster compounds; cubanes; magnetic properties; nickel; N.O ligands

Domaines: Chimie de coordination

Sophie Hameury, Laure Kayser, Roberto Pattacini, Patrick Rosa, Anne-Laure Barra, et al.. Synthesis, structures, and single-molecule magnet behaviour of high-nuclearity nickel(II) dicubane-type complexes with pyridyl-alcohol-ligands. ChemPlusChem, 2015, 80 (8), pp.1312-1320. ⟨10.1002/cplu.201500184⟩. ⟨hal-01199283⟩