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Synthesis, Crystal Structures, and Magnetic Properties of New Hexanuclear Mn III 2 Ln III 4 Complexes: SMM Behavior of the Terbium(III) Analogue
Author(s) -
Roy Shuvayan,
Ghosh Sagar,
Martins Daniel O. T. A.,
Tuna Floriana,
Mohanta Sasankasekhar
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201800792
Subject(s) - chemistry , terbium , crystallography , ligand (biochemistry) , magnetization , magnetic susceptibility , denticity , lanthanide , crystal structure , ion , magnetic anisotropy , stereochemistry , magnetic field , biochemistry , physics , receptor , organic chemistry , quantum mechanics
This investigation reports the syntheses, crystal structures, and magnetic properties of a series of isomorphous hexanuclear Mn III 2 Ln III 4 compounds of composition [Mn III 2 Ln III 4 L 1 2 L 2 2 (µ 3 ‐OH) 4 (µ 1,3 ‐Pivalate) 6 (NO 3 ) 2 ] · 2CH 3 CN {Ln = Tb ( 1 ), Dy ( 2 ), Ho ( 3 ), Er ( 4 )}, where H 2 L 1 is the Schiff base ligand that is obtained by [1+1] condensation of 3‐methoxysalicylaldehyde (HL 2 ) with 2‐amino‐2‐methyl‐1‐propanol. While the O(phenoxo)N(imine)O(alkoxo) pocket of the ligand [L 1 ] 2– binds a Mn III ion, the other pocket, O(methoxy)O(phenoxo), remains noncoordinated. In contrast, each of the O(methoxy)O(phenoxo) and O(phenoxo)O(aldehyde) sites of [L 2 ] – is occupied by a Ln III ion. Additionally, there are four µ 3 ‐hydroxo, six µ 1,3 ‐pivalate, and two chelating nitrate ligands, stabilizing the hexanuclear cores. Magnetic susceptibility (2–300 K) and magnetization ( M ) data reveal significant anisotropy in 1 – 4 . Detailed ac susceptibility measurements have revealed single molecule magnet (SMM) behavior in the Tb III analogue with U eff = 11.12 cm –1 and τ 0 = 1.04 × 10 –7 s under a 1000 Oe dc field and U eff = 10.42 cm –1 and τ 0 = 1.62 × 10 –7 s under a 3500 Oe dc field, while the other three analogues do not show slow relaxation of magnetization.