Abstracts 2005

Abstract of Publication No. 517

Andreas Sieber, Colette Boskovic, Roland Bircher, Oliver Waldmann, Stefan T. Ochsenbein, Grégory Chaboussant, Hans U. Güdel, Nadeschda Kirchner, Joris van Slageren, Wolfgang Wernsdorfer, Antonia Neels, Helen Stoeckli-Evans, Stefan Janssen, Fanni Juranyi and Hannu Mutka
Synthesis and Spectroscopic Characterization of a New Family of Ni4 Spin Clusters
Inorg. Chem. 44, 4315-4325 (2005)      Full Text (PDF)      DOI-Link      Supplementary Data (PDF)      Crystal Structure Data (CIF format)     

Abstract: A new family of tetranuclear Ni complexes [Ni4(ROH)4L4] (H2L = salicylidene-2-ethanolamine; R = Me (1) or Et (2)) has been synthesized and studied. Complexes 1 and 2 possess a [Ni4O4] core comprising a distorted cubane arrangement. Magnetic susceptibility and inelastic neutron scattering studies indicate a combination of ferromagnetic and antiferromagnetic pairwise exchange interactions between the four NiII centers, resulting in an S = 4 spin ground state. Magnetization measurements reveal an easy-axis-type magnetic anisotropy with D -0.93 cm–1 for both complexes. Despite the large magnetic anisotropy, no slow relaxation of the magnetization is observed down to 40 mK. To determine the origin of the low-temperature magnetic behavior, the magnetic anisotropy of complex 1 was probed in detail using inelastic neutron scattering and frequency domain magnetic resonance spectroscopy. The spectroscopic studies confirm the easy-axis-type anisotropy and indicate strong transverse interactions. These lead to rapid quantum tunneling of the magnetization, explaining the unexpected absence of slow magnetization relaxation for complex 1.

Last modified: 13.12.11 by Gabriela Frei