Tuning the coordination sphere of octahedral Dy(iii) complexes with silanolate/stannanolate ligands: synthesis, structures and slow relaxation of the magnetization

Abstract

We report the synthesis, crystal structures and magnetic investigations of four octahedral dysprosium complexes based on silanolate or stannanolate ligands of respective formula cis-[Dy(OSiPh₃)₂(THF)₄][BPh₄]·THF·C₆H₆ (1), cis-[Dy(OSnPh₃)₂(THF)₄][BPh₄]·THF·C₆H₆·C₆H₁₄ (2), fac-[Dy(OSiPh₃)₃(THF)₃]·THF (3) and fac-[Dy(OSiPh₃)₃(bipy)(THF)]·THF (4) (where THF = tetrahydrofuran, Ph = phenyl, bipy = 2,2′-bipyridine). Whereas complexes 1–3 exhibit a field-induced slow relaxation of the magnetization, 4 is a zero-field single-molecule magnet, which could be rationalized by the introduction of the bidentate bipy ligand providing a more important linearity of the (Si)O–Dy–O(Si) angle through distortion of the coordination sphere.