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Large Hexadecametallic {Mn III –Ln III } Wheels: Synthesis, Structural, Magnetic, and Theoretical Characterization
Author(s) -
Vignesh Kuduva R.,
Langley Stuart K.,
Moubaraki Boujemaa,
Murray Keith S.,
Rajaraman Gopalan
Publication year - 2015
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.201503424
Subject(s) - chemistry , ion , ferromagnetism , magnetic anisotropy , crystallography , ab initio quantum chemistry methods , ab initio , magnetic moment , antiferromagnetism , relaxation (psychology) , anisotropy , atomic physics , materials science , magnetic field , physics , condensed matter physics , magnetization , molecule , psychology , social psychology , organic chemistry , quantum mechanics
The synthesis, gas sorption studies, magnetic properties, and theoretical studies of new molecular wheels of core type {Mn III 8 Ln III 8 } (Ln=Dy, Ho, Er, Y and Yb), using the ligand mdeaH 2 , in the presence of ortho ‐toluic or benzoic acid are reported. From the seven wheels studied the {Mn 8 Dy 8 } and {Mn 8 Y 8 } analogues exhibit SMM behavior as determined from ac susceptibility experiments in a zero static magnetic field. From DFT calculations a S =16 ground state was determined for the {Mn 8 Y 8 } complex due to weak ferromagnetic Mn III –Mn III interactions. Ab initio CASSCF+RASSI‐SO calculations on the {Mn 8 Dy 8 } wheel estimated the Mn III –Dy III exchange interaction as −0.1 cm −1 . This weak exchange along with unfavorable single‐ion anisotropy of Dy III /Mn III ions, however, led to the observation of SMM behavior with fast magnetic relaxation. The orientation of the g‐anisotropy of the Dy III ions is found to be perpendicular to the plane of the wheel and this suggests the possibility of toroidal magnetic moments in the cluster. The {Mn 8 Ln 8 } clusters reported here are the largest heterometallic Mn III Ln III wheels and the largest {3d–4f} wheels to exhibit SMM behavior reported to date.