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Heterometallic [Mn 5 ‐Ln 4 ] Single‐Molecule Magnets with High Anisotropy Barriers
Author(s) -
Mereacre Valeriu,
Ako Ayuk M.,
Clérac Rodolphe,
Wernsdorfer Wolfgang,
Hewitt Ian J.,
Anson Christopher E.,
Powell Annie K.
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200800125
Subject(s) - isostructural , crystallography , lanthanide , single crystal , magnetization , chemistry , single molecule magnet , molecule , pyridine , magnetic anisotropy , anisotropy , crystal structure , ion , physics , magnetic field , organic chemistry , quantum mechanics , medicinal chemistry
The reaction of [Mn 6 O 2 (Piv) 10 (4‐Me‐py) 2.5 (PivH) 1.5 ] ( 1 ) (py: pyridine, Piv: pivilate) with N ‐methyldiethanolamine (mdeaH 2 ) and Ln(NO 3 ) 3 ⋅ 6 H 2 O in MeCN leads to a series of nonanuclear compounds [Mn 5 Ln 4 (O) 6 (mdea) 2 (mdeaH) 2 (Piv) 6 (NO 3 ) 4 (H 2 O) 2 ] ⋅ 2 MeCN (Ln=Tb III ( 2 ), Dy III ( 3 ), Ho III ( 4 ), Y III ( 5 )). Single‐crystal X‐ray diffraction shows that compounds 2 – 5 are isostructural, with the central core composed of two distorted {Mn IV Mn III Ln 2 O 4 } cubanes sharing a Mn IV vertex, representing a new heterometallic 3d–4f motif for this class of ligand. The four new compounds display single‐molecule magnet (SMM) behaviour, which is modulated by the lanthanide ion used. Moreover, the values found for Δ eff and τ o for 3 of 38.6 K and 3.0×10 −9 s respectively reveal that the complex 3 exhibits the highest energy barrier recorded so far for 3d–4f SMMs. The slow relaxation of the magnetisation for 3 was confirmed by μ‐SQUID measurements on an oriented single crystal and the observation of M versus H hysteresis loops below 1.9 K.